FreeBSD Handbook

The FreeBSD Documentation Project

Welcome to FreeBSD! This handbook covers the installation and day to day use of FreeBSD 4.9-RELEASE and FreeBSD 5.2.1-RELEASE. This manual is a work in progress and is the work of many individuals. Many sections do not yet exist and some of those that do exist need to be updated. If you are interested in helping with this project, send email to the FreeBSD documentation project mailing list. The latest version of this document is always available from the FreeBSD web site. It may also be downloaded in a variety of formats and compression options from the FreeBSD FTP server or one of the numerous mirror sites. If you would prefer to have a hard copy of the handbook, you can purchase one at the FreeBSD Mall. You may also want to search the handbook.

Redistribution and use in source (SGML DocBook) and 'compiled' forms (SGML, HTML, PDF, PostScript, RTF and so forth) with or without modification, are permitted provided that the following conditions are met:

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Important: THIS DOCUMENTATION IS PROVIDED BY THE FREEBSD DOCUMENTATION PROJECT "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FREEBSD DOCUMENTATION PROJECT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

FreeBSD is a registered trademark of Wind River Systems, Inc. This is expected to change soon.

3Com and HomeConnect are registered trademarks of 3Com Corporation.

3ware and Escalade are registered trademarks of 3ware Inc.

ARM is a registered trademark of ARM Limited.

Adaptec is a registered trademark of Adaptec, Inc.

Adobe, Acrobat, Acrobat Reader, and PostScript are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States and/or other countries.

Apple, FireWire, Mac, Macintosh, Mac OS, Quicktime, and TrueType are trademarks of Apple Computer, Inc., registered in the United States and other countries.

Corel and WordPerfect are trademarks or registered trademarks of Corel Corporation and/or its subsidiaries in Canada, the United States and/or other countries.

Sound Blaster is a trademark of Creative Technology Ltd. in the United States and/or other countries.

CVSup is a registered trademark of John D. Polstra.

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IBM, AIX, EtherJet, Netfinity, OS/2, PowerPC, PS/2, S/390, and ThinkPad are trademarks of International Business Machines Corporation in the United States, other countries, or both.

IEEE, POSIX, and 802 are registered trademarks of Institute of Electrical and Electronics Engineers, Inc. in the United States.

Intel, Celeron, EtherExpress, i386, i486, Itanium, Pentium, and Xeon are trademarks or registered trademarks of Intel Corporation or its subsidiaries in the United States and other countries.

Intuit and Quicken are registered trademarks and/or registered service marks of Intuit Inc., or one of its subsidiaries, in the United States and other countries.

Linux is a registered trademark of Linus Torvalds in the United States.

LSI Logic, AcceleRAID, eXtremeRAID, MegaRAID and Mylex are trademarks or registered trademarks of LSI Logic Corp.

M-Systems and DiskOnChip are trademarks or registered trademarks of M-Systems Flash Disk Pioneers, Ltd.

Macromedia, Flash, and Shockwave are trademarks or registered trademarks of Macromedia, Inc. in the United States and/or other countries.

Microsoft, FrontPage, MS-DOS, Outlook, Windows, Windows Media, and Windows NT are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.

Netscape and the Netscape Navigator are registered trademarks of Netscape Communications Corporation in the U.S. and other countries.

GateD and NextHop are registered and unregistered trademarks of NextHop in the U.S. and other countries.

Motif, OSF/1, and UNIX are registered trademarks and IT DialTone and The Open Group are trademarks of The Open Group in the United States and other countries.

Oracle is a registered trademark of Oracle Corporation.

PowerQuest and PartitionMagic are registered trademarks of PowerQuest Corporation in the United States and/or other countries.

RealNetworks, RealPlayer, and RealAudio are the registered trademarks of RealNetworks, Inc.

Red Hat, RPM, are trademarks or registered trademarks of Red Hat, Inc. in the United States and other countries.

SAP, R/3, and mySAP are trademarks or registered trademarks of SAP AG in Germany and in several other countries all over the world.

Sun, Sun Microsystems, Java, Java Virtual Machine, JavaServer Pages, JDK, JSP, JVM, Netra, Solaris, StarOffice, Sun Blade, Sun Enterprise, Sun Fire, SunOS, and Ultra are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries.

Symantec and Ghost are registered trademarks of Symantec Corporation in the United States and other countries.

MATLAB is a registered trademark of The MathWorks, Inc.

SpeedTouch is a trademark of Thomson

U.S. Robotics and Sportster are registered trademarks of U.S. Robotics Corporation.

VMware is a trademark of VMware, Inc.

Waterloo Maple and Maple are trademarks or registered trademarks of Waterloo Maple Inc.

Mathematica is a registered trademark of Wolfram Research, Inc.

XFree86 is a trademark of The XFree86 Project, Inc.

Ogg Vorbis and Xiph.Org are trademarks of Xiph.Org.

Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this document, and the FreeBSD Project was aware of the trademark claim, the designations have been followed by the ``™'' or the ``®'' symbol.


Table of Contents
Preface
I. Getting Started
1 Introduction
1.1 Synopsis
1.2 Welcome to FreeBSD!
1.3 About the FreeBSD Project
2 Installing FreeBSD
2.1 Synopsis
2.2 Pre-installation Tasks
2.3 Starting the Installation
2.4 Introducing Sysinstall
2.5 Allocating Disk Space
2.6 Choosing What to Install
2.7 Choosing Your Installation Media
2.8 Committing to the Installation
2.9 Post-installation
2.10 Supported Hardware
2.11 Troubleshooting
2.12 Advanced Installation Guide
2.13 Preparing Your Own Installation Media
3 UNIX Basics
3.1 Synopsis
3.2 Virtual Consoles and Terminals
3.3 Permissions
3.4 Directory Structure
3.5 Disk Organization
3.6 Mounting and Unmounting File Systems
3.7 Processes
3.8 Daemons, Signals, and Killing Processes
3.9 Shells
3.10 Text Editors
3.11 Devices and Device Nodes
3.12 Binary Formats
3.13 For More Information
4 Installing Applications: Packages and Ports
4.1 Synopsis
4.2 Overview of Software Installation
4.3 Finding Your Application
4.4 Using the Packages System
4.5 Using the Ports Collection
4.6 Post-installation Activities
4.7 Dealing with Broken Ports
5 The X Window System
5.1 Synopsis
5.2 Understanding X
5.3 Installing XFree86
5.4 XFree86 Configuration
5.5 Using Fonts in XFree86
5.6 The X Display Manager
5.7 Desktop Environments
II. System Administration
6 Configuration and Tuning
6.1 Synopsis
6.2 Initial Configuration
6.3 Core Configuration
6.4 Application Configuration
6.5 Starting Services
6.6 Configuring the cron Utility
6.7 Using rc under FreeBSD 5.X
6.8 Setting Up Network Interface Cards
6.9 Virtual Hosts
6.10 Configuration Files
6.11 Tuning with sysctl
6.12 Tuning Disks
6.13 Tuning Kernel Limits
6.14 Adding Swap Space
6.15 Power and Resource Management
7 The FreeBSD Booting Process
7.1 Synopsis
7.2 The Booting Problem
7.3 The MBR, and Boot Stages One, Two, and Three
7.4 Kernel Interaction During Boot
7.5 Device Hints
7.6 Init: Process Control Initialization
7.7 Shutdown Sequence
8 Users and Basic Account Management
8.1 Synopsis
8.2 Introduction
8.3 The Superuser Account
8.4 System Accounts
8.5 User Accounts
8.6 Modifying Accounts
8.7 Limiting Users
8.8 Personalizing Users
8.9 Groups
9 Configuring the FreeBSD Kernel
9.1 Synopsis
9.2 Why Build a Custom Kernel?
9.3 Building and Installing a Custom Kernel
9.4 The Configuration File
9.5 Making Device Nodes
9.6 If Something Goes Wrong
10 Security
10.1 Synopsis
10.2 Introduction
10.3 Securing FreeBSD
10.4 DES, MD5, and Crypt
10.5 One-time Passwords
10.6 KerberosIV
10.7 Kerberos5
10.8 Firewalls
10.9 OpenSSL
10.10 VPN over IPsec
10.11 OpenSSH
10.12 Mandatory Access Control (MAC)
10.13 File System Access Control Lists
10.14 FreeBSD Security Advisories
11 Printing
11.1 Synopsis
11.2 Introduction
11.3 Basic Setup
11.4 Advanced Printer Setup
11.5 Using Printers
11.6 Alternatives to the Standard Spooler
11.7 Troubleshooting
12 Storage
12.1 Synopsis
12.2 Device Names
12.3 Adding Disks
12.4 RAID
12.5 Creating and Using Optical Media (CDs & DVDs)
12.6 Creating and Using Floppy Disks
12.7 Creating and Using Data Tapes
12.8 Backups to Floppies
12.9 Backup Basics
12.10 Network, Memory, and File-Backed File Systems
12.11 File System Snapshots
12.12 File System Quotas
12.13 Encrypting Disk Partitions
13 The Vinum Volume Manager
13.1 Synopsis
13.2 Disks Are Too Small
13.3 Access Bottlenecks
13.4 Data Integrity
13.5 Vinum Objects
13.6 Some Examples
13.7 Object Naming
13.8 Configuring Vinum
13.9 Using Vinum for the Root Filesystem
14 Localization - I18N/L10N Usage and Setup
14.1 Synopsis
14.2 The Basics
14.3 Using Localization
14.4 Compiling I18N Programs
14.5 Localizing FreeBSD to Specific Languages
15 Desktop Applications
15.1 Synopsis
15.2 Browsers
15.3 Productivity
15.4 Document Viewers
15.5 Finance
15.6 Summary
16 Multimedia
16.1 Synopsis
16.2 Setting Up the Sound Card
16.3 MP3 Audio
16.4 Video Playback
16.5 Setting Up TV Cards
17 Serial Communications
17.1 Synopsis
17.2 Introduction
17.3 Terminals
17.4 Dial-in Service
17.5 Dial-out Service
17.6 Setting Up the Serial Console
18 PPP and SLIP
18.1 Synopsis
18.2 Using User PPP
18.3 Using Kernel PPP
18.4 Troubleshooting PPP Connections
18.5 Using PPP over Ethernet (PPPoE)
18.6 Using PPP over ATM (PPPoA)
18.7 Using SLIP
19 Advanced Networking
19.1 Synopsis
19.2 Gateways and Routes
19.3 Wireless Networking
19.4 Bluetooth
19.5 Bridging
19.6 NFS
19.7 Diskless Operation
19.8 ISDN
19.9 NIS/YP
19.10 DHCP
19.11 DNS
19.12 NTP
19.13 Network Address Translation
19.14 The inetd ``Super-Server''
19.15 Parallel Line IP (PLIP)
19.16 IPv6
20 Electronic Mail
20.1 Synopsis
20.2 Using Electronic Mail
20.3 sendmail Configuration
20.4 Changing Your Mail Transfer Agent
20.5 Troubleshooting
20.6 Advanced Topics
20.7 SMTP with UUCP
20.8 Using Mail with a Dialup Connection
20.9 SMTP Authentication
21 The Cutting Edge
21.1 Synopsis
21.2 FreeBSD-CURRENT vs. FreeBSD-STABLE
21.3 Synchronizing Your Source
21.4 Using make world
21.5 Tracking for Multiple Machines
22 Linux Binary Compatibility
22.1 Synopsis
22.2 Installation
22.3 Installing Mathematica®
22.4 Installing Maple
22.5 Installing MATLAB®
22.6 Installing Oracle®
22.7 Installing SAP® R/3®
22.8 Advanced Topics
III. Appendices
A. Obtaining FreeBSD
A.1 CDROM and DVD Publishers
A.2 FTP Sites
A.3 Anonymous CVS
A.4 Using CTM
A.5 Using CVSup
A.6 CVS Tags
A.7 AFS Sites
A.8 rsync Sites
B. Bibliography
B.1 Books & Magazines Specific to FreeBSD
B.2 Users' Guides
B.3 Administrators' Guides
B.4 Programmers' Guides
B.5 Operating System Internals
B.6 Security Reference
B.7 Hardware Reference
B.8 UNIX History
B.9 Magazines and Journals
C. Resources on the Internet
C.1 Mailing Lists
C.2 Usenet Newsgroups
C.3 World Wide Web Servers
C.4 Email Addresses
C.5 Shell Accounts
D. PGP Keys
D.1 Officers
D.2 Core Team Members
D.3 Developers
Colophon
List of Tables
2-1. Sample Device Inventory
2-2. Partition Layout for First Disk
2-3. Partition Layout for Subsequent Disks
2-4. Possible Security Profiles
2-5. FreeBSD ISO Image Names and Meanings
3-1. Disk Device Codes
12-1. Physical Disk Naming Conventions
13-1. Vinum Plex Organizations
19-1. Wiring a Parallel Cable for Networking
List of Figures
2-1. Kernel Configuration Menu
2-2. The Kernel Device Configuration Visual Interface
2-3. Expanded Driver List
2-4. Driver Configuration With No Conflicts
2-5. Sysinstall Main Menu
2-6. Typical Device Probe Results
2-7. Select Sysinstall Exit
2-8. Selecting Usage from Sysinstall Main Menu
2-9. Selecting Documentation Menu
2-10. Sysinstall Documentation Menu
2-11. Sysinstall Main Menu
2-12. Sysinstall Keymap Menu
2-13. Sysinstall Main Menu
2-14. Sysinstall Options
2-15. Begin Standard Installation
2-16. Select Drive for FDisk
2-17. Typical Fdisk Partitions before Editing
2-18. Fdisk Partition Using Entire Disk
2-19. Sysinstall Boot Manager Menu
2-20. Exit Select Drive
2-21. Sysinstall Disklabel Editor
2-22. Sysinstall Disklabel Editor with Auto Defaults
2-23. Free Space for Root Partition
2-24. Edit Root Partition Size
2-25. Choose the Root Partition Type
2-26. Choose the Root Mount Point
2-27. Sysinstall Disklabel Editor
2-28. Choose Distributions
2-29. Confirm Distributions
2-30. Choose Installation Media
2-31. Selecting an Ethernet Device
2-32. Set Network Configuration for ed0
2-33. Editing inetd.conf
2-34. Default Anonymous FTP Configuration
2-35. Edit the FTP Welcome Message
2-36. Editing exports
2-37. Security Profile Options
2-38. System Console Configuration Options
2-39. Screen Saver Options
2-40. Screen Saver Timeout
2-41. System Console Configuration Exit
2-42. Select Your Region
2-43. Select Your Country
2-44. Select Your Time Zone
2-45. Select Mouse Protocol Type
2-46. Set Mouse Protocol
2-47. Configure Mouse Port
2-48. Setting the Mouse Port
2-49. Enable the Mouse Daemon
2-50. Test the Mouse Daemon
2-51. Network Configuration Upper-level
2-52. Select a default MTA
2-53. Ntpdate Configuration
2-54. Network Configuration Lower-level
2-55. Select Configuration Method Menu
2-56. Select Default Desktop
2-57. Select Package Category
2-58. Select Packages
2-59. Install Packages
2-60. Confirm Package Installation
2-61. Select User
2-62. Add User Information
2-63. Exit User and Group Management
2-64. Exit Install
13-1. Concatenated Organization
13-2. Striped Organization
13-3. RAID-5 Organization
13-4. A Simple Vinum Volume
13-5. A Mirrored Vinum Volume
13-6. A Striped Vinum Volume
13-7. A Mirrored, Striped Vinum Volume
List of Examples
2-1. Using an Existing Partition Unchanged
2-2. Shrinking an Existing Partition
3-1. Sample Disk, Slice, and Partition Names
3-2. Conceptual Model of a Disk
4-1. Downloading a Package Manually and Installing It Locally
6-1. Creating a Swapfile on FreeBSD 4.X
6-2. Creating a Swapfile on FreeBSD 5.X
7-1. boot0 Screenshot
7-2. boot2 Screenshot
7-3. An Insecure Console in /etc/ttys
8-1. Configuring adduser and adding a user on FreeBSD 4.X
8-2. Adding a user on FreeBSD 5.X
8-3. rmuser Interactive Account Removal
8-4. Interactive chpass by Superuser
8-5. Interactive chpass by Normal User
8-6. Changing Your Password
8-7. Changing Another User's Password as the Superuser
8-8. Adding a Group Using pw(8)
8-9. Adding Somebody to a Group Using pw(8)
8-10. Using id(1) to Determine Group Membership
10-1. Using SSH to Create a Secure Tunnel for SMTP
12-1. Using dump over ssh
12-2. Using dump over ssh with RSH set
12-3. A Script for Creating a Bootable Floppy
12-4. Using vnconfig to Mount an Existing File System Image under FreeBSD 4.X
12-5. Creating a New File-Backed Disk with vnconfig
12-6. Using mdconfig to Mount an Existing File System Image under FreeBSD 5.X
12-7. Creating a New File-Backed Disk with mdconfig
12-8. Configure and Mount a File-Backed Disk with mdmfs
12-9. md Memory Disk under FreeBSD 4.X
12-10. Creating a New Memory-Based Disk with mdconfig
12-11. Creating a New Memory-Based Disk with mdmfs
17-1. Adding Terminal Entries to /etc/ttys
19-1. Mounting an Export with amd
19-2. Branch Office or Home Network
19-3. Head Office or Other LAN
19-4. Sending inetd a HangUP Signal
20-1. Configuring the sendmail Access Database
20-2. Mail Aliases
20-3. Example Virtual Domain Mail Map
A-1. Checking Out Something from -CURRENT (ls(1)) and Deleting It Again:
A-2. Checking Out the Version of ls(1) in the 3.X-STABLE Branch:
A-3. Creating a List of Changes (as Unified Diffs) to ls(1)
A-4. Finding Out What Other Module Names Can Be Used:

Preface

Intended Audience

The FreeBSD newcomer will find that the first section of this book guides the user through the FreeBSD installation process and gently introduces the concepts and conventions that underpin UNIX®. Working through this section requires little more than the desire to explore, and the ability to take on board new concepts as they are introduced.

Once you have travelled this far, the second, far larger, section of the Handbook is a comprehensive reference to all manner of topics of interest to FreeBSD system administrators. Some of these chapters may recommend that you do some prior reading, and this is noted in the synopsis at the beginning of each chapter.

For a list of additional sources of information, please see Appendix B.

Changes from the First Edition

This second edition is the culmination of over two years of work by the dedicated members of the FreeBSD Documentation Project. The following are the major changes in this new edition:

Organization of This Book

This book is split into three logically distinct sections. The first section, Getting Started, covers the installation and basic usage of FreeBSD. It is expected that the reader will follow these chapters in sequence, possibly skipping chapters covering familiar topics. The second section, System Administration, covers a broad collection of subjects that are of interest to more advanced FreeBSD users. Each section begins with a succinct synopsis that describes what the chapter covers and what the reader is expected to already know. This is meant to allow the casual reader to skip around to find chapters of interest. The third section contains appendices of reference information.

Chapter 1, Introduction

Introduces FreeBSD to a new user. It describes the history of the FreeBSD Project, its goals and development model.

Chapter 2, Installation

Walks a user through the entire installation process. Some advanced installation topics, such as installing through a serial console, are also covered.

Chapter 3, UNIX Basics

Covers the basic commands and functionality of the FreeBSD operating system. If you are familiar with Linux or another flavor of UNIX then you can probably skip this chapter.

Chapter 4, Installing Applications

Covers the installation of third-party software with both FreeBSD's innovative ``Ports Collection'' and standard binary packages.

Chapter 5, The X Window System

Describes the X Window System in general and using XFree86 on FreeBSD in particular. Also describes common desktop environments such as KDE and GNOME.

Chapter 6, Configuration and Tuning

Describes the parameters available for system administrators to tune a FreeBSD system for optimum performance. Also describes the various configuration files used in FreeBSD and where to find them.

Chapter 7, Booting Process

Describes the FreeBSD boot process and explains how to control this process with configuration options.

Chapter 8, Users and Basic Account Management

Describes the creation and manipulation of user accounts. Also discusses resource limitations that can be set on users and other account management tasks.

Chapter 9, Configuring the FreeBSD Kernel

Explains why you might need to configure a new kernel and provides detailed instructions for configuring, building, and installing a custom kernel.

Chapter 10, Security

Describes many different tools available to help keep your FreeBSD system secure, including Kerberos, IPsec, OpenSSH, and network firewalls.

Chapter 11, Printing

Describes managing printers on FreeBSD, including information about banner pages, printer accounting, and initial setup.

Chapter 12, Storage

Describes how to manage storage media and filesystems with FreeBSD. This includes physical disks, RAID arrays, optical and tape media, memory-backed disks, and network filesystems.

Chapter 13, Vinum

Describes how to use Vinum, a logical volume manager which provides device-independent logical disks, and software RAID-0, RAID-1 and RAID-5.

Chapter 14, Localization

Describes how to use FreeBSD in languages other than English. Covers both system and application level localization.

Chapter 15, Desktop Applications

Lists some common desktop applications, such as web browsers and productivity suites, and describes how to install them on FreeBSD.

Chapter 16, Multimedia

Shows how to set up sound and video playback support for your system. Also describes some sample audio and video applications.

Chapter 17, Serial Communications

Explains how to connect terminals and modems to your FreeBSD system for both dial in and dial out connections.

Chapter 18, PPP and SLIP

Describes how to use PPP, SLIP, or PPP over Ethernet to connect to remote systems with FreeBSD.

Chapter 19, Advanced Networking

Describes many networking topics, including sharing an Internet connection with other computers on your LAN, using network filesystems, sharing account information via NIS, setting up a name server, and much more.

Chapter 20, Electronic Mail

Explains the different components of an email server and dives into simple configuration topics for the most popular mail server software: sendmail.

Chapter 21, The Cutting Edge

Explains the differences between FreeBSD-STABLE, FreeBSD-CURRENT, and FreeBSD releases. Describes which users would benefit from tracking a development system and outlines that process.

Chapter 22, Linux Binary Compatibility

Describes the Linux compatibility features of FreeBSD. Also provides detailed installation instructions for many popular Linux applications such as Oracle, SAP R/3, and Mathematica®.

Appendix A, Obtaining FreeBSD

Lists different sources for obtaining FreeBSD media on CDROM or DVD as well as different sites on the Internet that allow you to download and install FreeBSD.

Appendix B, Bibliography

This book touches on many different subjects that may leave you hungry for a more detailed explanation. The bibliography lists many excellent books that are referenced in the text.

Appendix C, Resources on the Internet

Describes the many forums available for FreeBSD users to post questions and engage in technical conversations about FreeBSD.

Appendix D, PGP Keys

Lists the PGP fingerprints of several FreeBSD Developers.

Conventions used in this book

To provide a consistent and easy to read text, several conventions are followed throughout the book.

Typographic Conventions

Italic

An italic font is used for filenames, URLs, emphasized text, and the first usage of technical terms.

Monospace

A monospaced font is used for error messages, commands, environment variables, names of ports, hostnames, user names, group names, device names, variables, and code fragments.

Bold

A bold font is used for applications, commands, and keys.

User Input

Keys are shown in bold to stand out from other text. Key combinations that are meant to be typed simultaneously are shown with `+' between the keys, such as:

Ctrl+Alt+Del

Meaning the user should type the Ctrl, Alt,and Del keys at the same time.

Keys that are meant to be typed in sequence will be separated with commas, for example:

Ctrl+X, Ctrl+S

Would mean that the user is expected to type the Ctrl and X keys simultaneously and then to type the Ctrl and S keys simultaneously.

Examples

Examples starting with E:\> indicate a MS-DOS® command. Unless otherwise noted, these commands may be executed from a ``Command Prompt'' window in a modern Microsoft® Windows® environment.

E:\> tools\fdimage floppies\kern.flp A:

Examples starting with # indicate a command that must be invoked as the superuser in FreeBSD. You can login as root to type the command, or login as your normal account and use su(1) to gain superuser privileges.

# dd if=kern.flp of=/dev/fd0

Examples starting with % indicate a command that should be invoked from a normal user account. Unless otherwise noted, C-shell syntax is used for setting environment variables and other shell commands.

% top

Acknowledgments

The book you are holding represents the efforts of many hundreds of people around the world. Whether they sent in fixes for typos, or submitted complete chapters, all the contributions have been useful.

Several companies have supported the development of this document by paying authors to work on it full-time, paying for publication, etc. In particular, BSDi (subsequently acquired by Wind River Systems) paid members of the FreeBSD Documentation Project to work on improving this book full time leading up to the publication of the first printed edition in March 2000 (ISBN 1-57176-241-8). Wind River Systems then paid several additional authors to make a number of improvements to the print-output infrastructure and to add additional chapters to the text. This work culminated in the publication of the second printed edition in November 2001 (ISBN 1-57176-303-1).

I. Getting Started

This part of the FreeBSD Handbook is for users and administrators who are new to FreeBSD. These chapters:

  • Introduce you to FreeBSD.

  • Guide you through the installation process.

  • Teach you UNIX basics and fundamentals.

  • Show you how to install the wealth of third party applications available for FreeBSD.

  • Introduce you to X, the UNIX windowing system, and detail how to configure a desktop environment that makes you more productive.

We have tried to keep the number of forward references in the text to a minimum so that you can read this section of the Handbook from front to back with the minimum page flipping required.


Chapter 1 Introduction

Restructured, reorganized, and parts rewritten by Jim Mock.

1.1 Synopsis

Thank you for your interest in FreeBSD! The following chapter covers various aspects of the FreeBSD Project, such as its history, goals, development model, and so on.

After reading this chapter, you will know:

  • How FreeBSD relates to other computer operating systems.

  • The history of the FreeBSD Project.

  • The goals of the FreeBSD Project.

  • The basics of the FreeBSD open-source development model.

  • And of course: where the name ``FreeBSD'' comes from.


1.2 Welcome to FreeBSD!

FreeBSD is a 4.4BSD-Lite based operating system for Intel (x86), DEC Alpha™, and Sun UltraSPARC® computers. Ports to other architectures are also underway. You can also read about the history of FreeBSD, or the current release. If you are interested in contributing something to the Project (code, hardware, unmarked bills), see the Contributing to FreeBSD article.


1.2.1 What Can FreeBSD Do?

FreeBSD has many noteworthy features. Some of these are:

  • Preemptive multitasking with dynamic priority adjustment to ensure smooth and fair sharing of the computer between applications and users, even under the heaviest of loads.

  • Multi-user facilities which allow many people to use a FreeBSD system simultaneously for a variety of things. This means, for example, that system peripherals such as printers and tape drives are properly shared between all users on the system or the network and that individual resource limits can be placed on users or groups of users, protecting critical system resources from over-use.

  • Strong TCP/IP networking with support for industry standards such as SLIP, PPP, NFS, DHCP, and NIS. This means that your FreeBSD machine can interoperate easily with other systems as well as act as an enterprise server, providing vital functions such as NFS (remote file access) and email services or putting your organization on the Internet with WWW, FTP, routing and firewall (security) services.

  • Memory protection ensures that applications (or users) cannot interfere with each other. One application crashing will not affect others in any way.

  • FreeBSD is a 32-bit operating system (64-bit on the Alpha and UltraSPARC) and was designed as such from the ground up.

  • The industry standard X Window System (X11R6) provides a graphical user interface (GUI) for the cost of a common VGA card and monitor and comes with full sources.

  • Binary compatibility with many programs built for Linux, SCO, SVR4, BSDI and NetBSD.

  • Thousands of ready-to-run applications are available from the FreeBSD ports and packages collection. Why search the net when you can find it all right here?

  • Thousands of additional and easy-to-port applications are available on the Internet. FreeBSD is source code compatible with most popular commercial UNIX systems and thus most applications require few, if any, changes to compile.

  • Demand paged virtual memory and ``merged VM/buffer cache'' design efficiently satisfies applications with large appetites for memory while still maintaining interactive response to other users.

  • SMP support for machines with multiple CPUs.

  • A full complement of C, C++, Fortran, and Perl development tools. Many additional languages for advanced research and development are also available in the ports and packages collection.

  • Source code for the entire system means you have the greatest degree of control over your environment. Why be locked into a proprietary solution at the mercy of your vendor when you can have a truly open system?

  • Extensive online documentation.

  • And many more!

FreeBSD is based on the 4.4BSD-Lite release from Computer Systems Research Group (CSRG) at the University of California at Berkeley, and carries on the distinguished tradition of BSD systems development. In addition to the fine work provided by CSRG, the FreeBSD Project has put in many thousands of hours in fine tuning the system for maximum performance and reliability in real-life load situations. As many of the commercial giants struggle to field PC operating systems with such features, performance and reliability, FreeBSD can offer them now!

The applications to which FreeBSD can be put are truly limited only by your own imagination. From software development to factory automation, inventory control to azimuth correction of remote satellite antennae; if it can be done with a commercial UNIX product then it is more than likely that you can do it with FreeBSD too! FreeBSD also benefits significantly from literally thousands of high quality applications developed by research centers and universities around the world, often available at little to no cost. Commercial applications are also available and appearing in greater numbers every day.

Because the source code for FreeBSD itself is generally available, the system can also be customized to an almost unheard of degree for special applications or projects, and in ways not generally possible with operating systems from most major commercial vendors. Here is just a sampling of some of the applications in which people are currently using FreeBSD:

  • Internet Services: The robust TCP/IP networking built into FreeBSD makes it an ideal platform for a variety of Internet services such as:

    • FTP servers

    • World Wide Web servers (standard or secure [SSL])

    • Firewalls and NAT (``IP masquerading'') gateways

    • Electronic Mail servers

    • USENET News or Bulletin Board Systems

    • And more...

    With FreeBSD, you can easily start out small with an inexpensive 386 class PC and upgrade all the way up to a quad-processor Xeon with RAID storage as your enterprise grows.

  • Education: Are you a student of computer science or a related engineering field? There is no better way of learning about operating systems, computer architecture and networking than the hands on, under the hood experience that FreeBSD can provide. A number of freely available CAD, mathematical and graphic design packages also make it highly useful to those whose primary interest in a computer is to get other work done!

  • Research: With source code for the entire system available, FreeBSD is an excellent platform for research in operating systems as well as other branches of computer science. FreeBSD's freely available nature also makes it possible for remote groups to collaborate on ideas or shared development without having to worry about special licensing agreements or limitations on what may be discussed in open forums.

  • Networking: Need a new router? A name server (DNS)? A firewall to keep people out of your internal network? FreeBSD can easily turn that unused 386 or 486 PC sitting in the corner into an advanced router with sophisticated packet-filtering capabilities.

  • X Window workstation: FreeBSD is a fine choice for an inexpensive X terminal solution, either using the freely available XFree86 server or one of the excellent commercial servers provided by Xi Graphics. Unlike an X terminal, FreeBSD allows many applications to be run locally if desired, thus relieving the burden on a central server. FreeBSD can even boot ``diskless'', making individual workstations even cheaper and easier to administer.

  • Software Development: The basic FreeBSD system comes with a full complement of development tools including the renowned GNU C/C++ compiler and debugger.

FreeBSD is available in both source and binary form on CDROM, DVD, and via anonymous FTP. Please see Appendix A for more information about obtaining FreeBSD.


1.2.2 Who Uses FreeBSD?

FreeBSD is used to power some of the biggest sites on the Internet, including:

and many more.


1.3 About the FreeBSD Project

The following section provides some background information on the project, including a brief history, project goals, and the development model of the project.


1.3.1 A Brief History of FreeBSD

Contributed by Jordan Hubbard.

The FreeBSD project had its genesis in the early part of 1993, partially as an outgrowth of the ``Unofficial 386BSD Patchkit'' by the patchkit's last 3 coordinators: Nate Williams, Rod Grimes and myself.

Our original goal was to produce an intermediate snapshot of 386BSD in order to fix a number of problems with it that the patchkit mechanism just was not capable of solving. Some of you may remember the early working title for the project being ``386BSD 0.5'' or ``386BSD Interim'' in reference to that fact.

386BSD was Bill Jolitz's operating system, which had been up to that point suffering rather severely from almost a year's worth of neglect. As the patchkit swelled ever more uncomfortably with each passing day, we were in unanimous agreement that something had to be done and decided to assist Bill by providing this interim ``cleanup'' snapshot. Those plans came to a rude halt when Bill Jolitz suddenly decided to withdraw his sanction from the project without any clear indication of what would be done instead.

It did not take us long to decide that the goal remained worthwhile, even without Bill's support, and so we adopted the name ``FreeBSD'', coined by David Greenman. Our initial objectives were set after consulting with the system's current users and, once it became clear that the project was on the road to perhaps even becoming a reality, I contacted Walnut Creek CDROM with an eye toward improving FreeBSD's distribution channels for those many unfortunates without easy access to the Internet. Walnut Creek CDROM not only supported the idea of distributing FreeBSD on CD but also went so far as to provide the project with a machine to work on and a fast Internet connection. Without Walnut Creek CDROM's almost unprecedented degree of faith in what was, at the time, a completely unknown project, it is quite unlikely that FreeBSD would have gotten as far, as fast, as it has today.

The first CDROM (and general net-wide) distribution was FreeBSD 1.0, released in December of 1993. This was based on the 4.3BSD-Lite (``Net/2'') tape from U.C. Berkeley, with many components also provided by 386BSD and the Free Software Foundation. It was a fairly reasonable success for a first offering, and we followed it with the highly successful FreeBSD 1.1 release in May of 1994.

Around this time, some rather unexpected storm clouds formed on the horizon as Novell and U.C. Berkeley settled their long-running lawsuit over the legal status of the Berkeley Net/2 tape. A condition of that settlement was U.C. Berkeley's concession that large parts of Net/2 were ``encumbered'' code and the property of Novell, who had in turn acquired it from AT&T some time previously. What Berkeley got in return was Novell's ``blessing'' that the 4.4BSD-Lite release, when it was finally released, would be declared unencumbered and all existing Net/2 users would be strongly encouraged to switch. This included FreeBSD, and the project was given until the end of July 1994 to stop shipping its own Net/2 based product. Under the terms of that agreement, the project was allowed one last release before the deadline, that release being FreeBSD 1.1.5.1.

FreeBSD then set about the arduous task of literally re-inventing itself from a completely new and rather incomplete set of 4.4BSD-Lite bits. The ``Lite'' releases were light in part because Berkeley's CSRG had removed large chunks of code required for actually constructing a bootable running system (due to various legal requirements) and the fact that the Intel port of 4.4 was highly incomplete. It took the project until November of 1994 to make this transition, at which point it released FreeBSD 2.0 to the net and on CDROM (in late December). Despite being still more than a little rough around the edges, the release was a significant success and was followed by the more robust and easier to install FreeBSD 2.0.5 release in June of 1995.

We released FreeBSD 2.1.5 in August of 1996, and it appeared to be popular enough among the ISP and commercial communities that another release along the 2.1-STABLE branch was merited. This was FreeBSD 2.1.7.1, released in February 1997 and capping the end of mainstream development on 2.1-STABLE. Now in maintenance mode, only security enhancements and other critical bug fixes will be done on this branch (RELENG_2_1_0).

FreeBSD 2.2 was branched from the development mainline (``-CURRENT'') in November 1996 as the RELENG_2_2 branch, and the first full release (2.2.1) was released in April 1997. Further releases along the 2.2 branch were done in the summer and fall of '97, the last of which (2.2.8) appeared in November 1998. The first official 3.0 release appeared in October 1998 and spelled the beginning of the end for the 2.2 branch.

The tree branched again on Jan 20, 1999, leading to the 4.0-CURRENT and 3.X-STABLE branches. From 3.X-STABLE, 3.1 was released on February 15, 1999, 3.2 on May 15, 1999, 3.3 on September 16, 1999, 3.4 on December 20, 1999, and 3.5 on June 24, 2000, which was followed a few days later by a minor point release update to 3.5.1, to incorporate some last-minute security fixes to Kerberos. This will be the final release in the 3.X branch.

There was another branch on March 13, 2000, which saw the emergence of the 4.X-STABLE branch, now considered to be the ``current -stable branch''. There have been several releases from it so far: 4.0-RELEASE was introduced in March 2000, and the most recent 4.9-RELEASE came out in October 2003. There will be additional releases along the 4.X-stable (RELENG_4) branch well into 2003.

The long-awaited 5.0-RELEASE was announced on January 19, 2003. The culmination of nearly three years of work, this release started FreeBSD on the path of advanced multiprocessor and application thread support and introduced support for the UltraSPARC and ia64 platforms. This release was followed by 5.1 in June of 2003. Besides a number of new features, the 5.X releases also contain a number of major developments in the underlying system architecture. Along with these advances, however, comes a system that incorporates a tremendous amount of new and not-widely-tested code. For this reason, the 5.X releases are considered ``New Technology'' releases, while the 4.X series function as ``Production'' releases. In time, 5.X will be declared stable and work will commence on the next development branch, 6.0-CURRENT.

For now, long-term development projects continue to take place in the 5.X-CURRENT (trunk) branch, and SNAPshot releases of 5.X on CDROM (and, of course, on the net) are continually made available from the snapshot server as work progresses.


1.3.2 FreeBSD Project Goals

Contributed by Jordan Hubbard.

The goals of the FreeBSD Project are to provide software that may be used for any purpose and without strings attached. Many of us have a significant investment in the code (and project) and would certainly not mind a little financial compensation now and then, but we are definitely not prepared to insist on it. We believe that our first and foremost ``mission'' is to provide code to any and all comers, and for whatever purpose, so that the code gets the widest possible use and provides the widest possible benefit. This is, I believe, one of the most fundamental goals of Free Software and one that we enthusiastically support.

That code in our source tree which falls under the GNU General Public License (GPL) or Library General Public License (LGPL) comes with slightly more strings attached, though at least on the side of enforced access rather than the usual opposite. Due to the additional complexities that can evolve in the commercial use of GPL software we do, however, prefer software submitted under the more relaxed BSD copyright when it is a reasonable option to do so.


1.3.3 The FreeBSD Development Model

Contributed by Satoshi Asami.

The development of FreeBSD is a very open and flexible process, being literally built from the contributions of hundreds of people around the world, as can be seen from our list of contributors. FreeBSD's development infrastructure allow these hundreds of developers to collaborate over the Internet. We are constantly on the lookout for new developers and ideas, and those interested in becoming more closely involved with the project need simply contact us at the FreeBSD technical discussions mailing list. The FreeBSD announcements mailing list is also available to those wishing to make other FreeBSD users aware of major areas of work.

Useful things to know about the FreeBSD project and its development process, whether working independently or in close cooperation:

The CVS repository

The central source tree for FreeBSD is maintained by CVS (Concurrent Versions System), a freely available source code control tool that comes bundled with FreeBSD. The primary CVS repository resides on a machine in Santa Clara CA, USA from where it is replicated to numerous mirror machines throughout the world. The CVS tree, which contains the -CURRENT and -STABLE trees, can all be easily replicated to your own machine as well. Please refer to the Synchronizing your source tree section for more information on doing this.

The committers list

The committers are the people who have write access to the CVS tree, and are authorized to make modifications to the FreeBSD source (the term ``committer'' comes from the cvs(1) commit command, which is used to bring new changes into the CVS repository). The best way of making submissions for review by the committers list is to use the send-pr(1) command. If something appears to be jammed in the system, then you may also reach them by sending mail to the FreeBSD committer's mailing list.

The FreeBSD core team

The FreeBSD core team would be equivalent to the board of directors if the FreeBSD Project were a company. The primary task of the core team is to make sure the project, as a whole, is in good shape and is heading in the right directions. Inviting dedicated and responsible developers to join our group of committers is one of the functions of the core team, as is the recruitment of new core team members as others move on. The current core team was elected from a pool of committer candidates in June 2002. Elections are held every 2 years.

Some core team members also have specific areas of responsibility, meaning that they are committed to ensuring that some large portion of the system works as advertised. For a complete list of FreeBSD developers and their areas of responsibility, please see the Contributors List

Note: Most members of the core team are volunteers when it comes to FreeBSD development and do not benefit from the project financially, so ``commitment'' should also not be misconstrued as meaning ``guaranteed support.'' The ``board of directors'' analogy above is not very accurate, and it may be more suitable to say that these are the people who gave up their lives in favor of FreeBSD against their better judgment!

Outside contributors

Last, but definitely not least, the largest group of developers are the users themselves who provide feedback and bug fixes to us on an almost constant basis. The primary way of keeping in touch with FreeBSD's more non-centralized development is to subscribe to the FreeBSD technical discussions mailing list where such things are discussed. See Appendix C for more information about the various FreeBSD mailing lists.

The FreeBSD Contributors List is a long and growing one, so why not join it by contributing something back to FreeBSD today?

Providing code is not the only way of contributing to the project; for a more complete list of things that need doing, please refer to the FreeBSD Project web site.

In summary, our development model is organized as a loose set of concentric circles. The centralized model is designed for the convenience of the users of FreeBSD, who are provided with an easy way of tracking one central code base, not to keep potential contributors out! Our desire is to present a stable operating system with a large set of coherent application programs that the users can easily install and use -- this model works very well in accomplishing that.

All we ask of those who would join us as FreeBSD developers is some of the same dedication its current people have to its continued success!


1.3.4 The Current FreeBSD Release

FreeBSD is a freely available, full source 4.4BSD-Lite based release for Intel i386™, i486™, Pentium®, Pentium Pro, Celeron®, Pentium II, Pentium III, Pentium 4 (or compatible), Xeon™, DEC Alpha and Sun UltraSPARC based computer systems. It is based primarily on software from U.C. Berkeley's CSRG group, with some enhancements from NetBSD, OpenBSD, 386BSD, and the Free Software Foundation.

Since our release of FreeBSD 2.0 in late 94, the performance, feature set, and stability of FreeBSD has improved dramatically. The largest change is a revamped virtual memory system with a merged VM/file buffer cache that not only increases performance, but also reduces FreeBSD's memory footprint, making a 5 MB configuration a more acceptable minimum. Other enhancements include full NIS client and server support, transaction TCP support, dial-on-demand PPP, integrated DHCP support, an improved SCSI subsystem, ISDN support, support for ATM, FDDI, Fast and Gigabit Ethernet (1000 Mbit) adapters, improved support for the latest Adaptec controllers, and many thousands of bug fixes.

In addition to the base distributions, FreeBSD offers a ported software collection with thousands of commonly sought-after programs. At the time of this printing, there were over 10,000 ports! The list of ports ranges from http (WWW) servers, to games, languages, editors, and almost everything in between. The entire ports collection requires approximately 300 MB of storage, all ports being expressed as ``deltas'' to their original sources. This makes it much easier for us to update ports, and greatly reduces the disk space demands made by the older 1.0 ports collection. To compile a port, you simply change to the directory of the program you wish to install, type make install, and let the system do the rest. The full original distribution for each port you build is retrieved dynamically off the CDROM or a local FTP site, so you need only enough disk space to build the ports you want. Almost every port is also provided as a pre-compiled ``package'', which can be installed with a simple command (pkg_add) by those who do not wish to compile their own ports from source. More information on packages and ports can be found in Chapter 4.

A number of additional documents which you may find very helpful in the process of installing and using FreeBSD may now also be found in the /usr/share/doc directory on any recent FreeBSD machine. You may view the locally installed manuals with any HTML capable browser using the following URLs:

You can also view the master (and most frequently updated) copies at http://www.FreeBSD.org/.


Chapter 2 Installing FreeBSD

Restructured, reorganized, and parts rewritten by Jim Mock. The sysinstall walkthrough, screenshots, and general copy by Randy Pratt.

2.1 Synopsis

FreeBSD is provided with a text-based, easy to use installation program called sysinstall. This is the default installation program for FreeBSD, although vendors are free to provide their own installation suite if they wish. This chapter describes how to use sysinstall to install FreeBSD.

After reading this chapter, you will know:

  • How to create the FreeBSD installation disks.

  • How FreeBSD refers to, and subdivides, your hard disks.

  • How to start sysinstall.

  • The questions sysinstall will ask you, what they mean, and how to answer them.

Before reading this chapter, you should:

  • Read the supported hardware list that shipped with the version of FreeBSD you are installing, and verify that your hardware is supported.

Note: In general, these installation instructions are written for i386 (``PC compatible'') architecture computers. Where applicable, instructions specific to other platforms (for example, Alpha) will be listed. Although this guide is kept as up to date as possible, you may find minor differences between the installer and what is shown here. It is suggested that you use this chapter as a general guide rather than a literal installation manual.


2.2 Pre-installation Tasks

2.2.1 Inventory Your Computer

Before installing FreeBSD you should attempt to inventory the components in your computer. The FreeBSD installation routines will show you the components (hard disks, network cards, CDROM drives, and so forth) with their model number and manufacturer. FreeBSD will also attempt to determine the correct configuration for these devices, which includes information about IRQ and IO port usage. Due to the vagaries of PC hardware this process is not always completely successful, and you may need to correct FreeBSD's determination of your configuration.

If you already have another operating system installed, such as Windows or Linux, it is a good idea to use the facilities provided by those operating systems to see how your hardware is already configured. If you are not sure what settings an expansion card is using, you may find it printed on the card itself. Popular IRQ numbers are 3, 5, and 7, and IO port addresses are normally written as hexadecimal numbers, such as 0x330.

We recommend you print or write down this information before installing FreeBSD. It may help to use a table, like this:

Table 2-1. Sample Device Inventory

Device Name IRQ IO port(s) Notes
First hard disk N/A N/A 40 GB, made by Seagate, first IDE master
CDROM N/A N/A First IDE slave
Second hard disk N/A N/A 20 GB, made by IBM, second IDE master
First IDE controller 14 0x1f0  
Network card N/A N/A Intel® 10/100
Modem N/A N/A 3Com® 56K faxmodem, on COM1
...      

2.2.2 Backup Your Data

If the computer you will be installing FreeBSD on contains valuable data, then ensure you have it backed up, and that you have tested the backups before installing FreeBSD. The FreeBSD installation routine will prompt you before writing any data to your disk, but once that process has started it cannot be undone.


2.2.3 Decide Where to Install FreeBSD

If you want FreeBSD to use your entire hard disk, then there is nothing more to concern yourself with at this point -- you can skip this section.

However, if you need FreeBSD to co-exist with other operating systems then you need to have a rough understanding of how data is laid out on the disk, and how this affects you.


2.2.3.1 Disk Layouts for the i386

A PC disk can be divided into discrete chunks. These chunks are called partitions. By design, the PC only supports four partitions per disk. These partitions are called primary partitions. To work around this limitation and allow more than four partitions, a new partition type was created, the extended partition. A disk may contain only one extended partition. Special partitions, called logical partitions, can be created inside this extended partition.

Each partition has a partition ID, which is a number used to identify the type of data on the partition. FreeBSD partitions have the partition ID of 165.

In general, each operating system that you use will identify partitions in a particular way. For example, DOS, and its descendants, like Windows, assign each primary and logical partition a drive letter, starting with C:.

FreeBSD must be installed into a primary partition. FreeBSD can keep all its data, including any files that you create, on this one partition. However, if you have multiple disks, then you can create a FreeBSD partition on all, or some, of them. When you install FreeBSD, you must have one partition available. This might be a blank partition that you have prepared, or it might be an existing partition that contains data that you no longer care about.

If you are already using all the partitions on all your disks, then you will have to free one of them for FreeBSD using the tools provided by the other operating systems you use (e.g., fdisk on DOS or Windows).

If you have a spare partition then you can use that. However, you may need to shrink one or more of your existing partitions first.

A minimal installation of FreeBSD takes as little as 100 MB of disk space. However, that is a very minimal install, leaving almost no space for your own files. A more realistic minimum is 250 MB without a graphical environment, and 350 MB or more if you want a graphical user interface. If you intend to install a lot of third party software as well, then you will need more space.

You can use a commercial tool such as PartitionMagic® to resize your partitions to make space for FreeBSD. The tools directory on the CDROM contains two free software tools which can carry out this task, namely FIPS and PResizer. FIPS, PResizer, and PartitionMagic can resize FAT16 and FAT32 partitions -- used in MS-DOS through Windows ME. PartitionMagic is the only known application that can resize NTFS. Documentation for both of these is available in the same directory.

Warning: Incorrect use of these tools can delete the data on your disk. Be sure that you have recent, working backups before using them.

Example 2-1. Using an Existing Partition Unchanged

Suppose that you have a computer with a single 4 GB disk that already has a version of Windows installed, and you have split the disk into two drive letters, C: and D:, each of which is 2 GB in size. You have 1 GB of data on C:, and 0.5 GB of data on D:.

This means that your disk has two partitions on it, one per drive letter. You can copy all your existing data from D: to C:, which will free up the second partition, ready for FreeBSD.

Example 2-2. Shrinking an Existing Partition

Suppose that you have a computer with a single 4 GB disk that already has a version of Windows installed. When you installed Windows you created one large partition, giving you a C: drive that is 4 GB in size. You are currently using 1.5 GB of space, and want FreeBSD to have 2 GB of space.

In order to install FreeBSD you will need to either:

  1. Backup your Windows data, and then reinstall Windows, asking for a 2 GB partition at install time.

  2. Use one of the tools such as PartitionMagic, described above, to shrink your Windows partition.


2.2.3.2 Disk Layouts for the Alpha

You will need a dedicated disk for FreeBSD on the Alpha. It is not possible to share a disk with another operating system at this time. Depending on the specific Alpha machine you have, this disk can either be a SCSI disk or an IDE disk, as long as your machine is capable of booting from it.

Following the conventions of the Digital / Compaq manuals all SRM input is shown in uppercase. SRM is case insensitive.

To find the names and types of disks in your machine, use the SHOW DEVICE command from the SRM console prompt:

>>>SHOW DEVICE
dka0.0.0.4.0               DKA0           TOSHIBA CD-ROM XM-57  3476
dkc0.0.0.1009.0            DKC0                       RZ1BB-BS  0658
dkc100.1.0.1009.0          DKC100             SEAGATE ST34501W  0015
dva0.0.0.0.1               DVA0
ewa0.0.0.3.0               EWA0              00-00-F8-75-6D-01
pkc0.7.0.1009.0            PKC0                  SCSI Bus ID 7  5.27
pqa0.0.0.4.0               PQA0                       PCI EIDE
pqb0.0.1.4.0               PQB0                       PCI EIDE

This example is from a Digital Personal Workstation 433au and shows three disks attached to the machine. The first is a CDROM drive called DKA0 and the other two are disks and are called DKC0 and DKC100 respectively.

Disks with names of the form DKx are SCSI disks. For example DKA100 refers to a SCSI disk with SCSI target ID 1 on the first SCSI bus (A), whereas DKC300 refers to a SCSI disk with SCSI ID 3 on the third SCSI bus (C). Devicename PKx refers to the SCSI host bus adapter. As seen in the SHOW DEVICE output SCSI CDROM drives are treated as any other SCSI hard disk drive.

IDE disks have names similar to DQx, while PQx is the associated IDE controller.


2.2.4 Collect Your Network Configuration Details

If you intend to connect to a network as part of your FreeBSD installation (for example, if you will be installing from an FTP site or an NFS server), then you need to know your network configuration. You will be prompted for this information during the installation so that FreeBSD can connect to the network to complete the install.


2.2.4.1 Connecting to an Ethernet Network or Cable/DSL Modem

If you connect to an Ethernet network, or you have an Internet connection using an Ethernet adapter via cable or DSL, then you will need the following information:

  1. IP address

  2. IP address of the default gateway

  3. Hostname

  4. DNS server IP addresses

  5. Subnet Mask

If you do not know this information, then ask your system administrator or service provider. They may say that this information is assigned automatically, using DHCP. If so, make a note of this.


2.2.4.2 Connecting Using a Modem

If you dial up to an ISP using a regular modem then you can still install FreeBSD over the Internet, it will just take a very long time.

You will need to know:

  1. The phone number to dial for your ISP

  2. The COM: port your modem is connected to

  3. The username and password for your ISP account


2.2.5 Check for FreeBSD Errata

Although the FreeBSD project strives to ensure that each release of FreeBSD is as stable as possible, bugs do occasionally creep into the process. On very rare occasions those bugs affect the installation process. As these problems are discovered and fixed, they are noted in the FreeBSD Errata, which is found on the FreeBSD web site. You should check the errata before installing to make sure that there are no late-breaking problems which you should be aware of.

Information about all the releases, including the errata for each release, can be found on the release information section of the FreeBSD web site.


2.2.6 Obtain the FreeBSD Installation Files

The FreeBSD installation process can install FreeBSD from files located in the any of the following places:

Local Media

  • A CDROM or DVD

  • A DOS partition on the same computer

  • A SCSI or QIC tape

  • Floppy disks

Network

  • An FTP site, going through a firewall, or using an HTTP proxy, as necessary

  • An NFS server

  • A dedicated parallel or serial connection

If you have purchased FreeBSD on CD or DVD then you already have everything you need, and should proceed to the next section (Section 2.2.7).

If you have not obtained the FreeBSD installation files you should skip ahead to Section 2.13 which explains how to prepare to install FreeBSD from any of the above. After reading that section, you should come back here, and read on to Section 2.2.7.


2.2.7 Prepare the Boot Media

The FreeBSD installation process is started by booting your computer into the FreeBSD installer--it is not a program you run within another operating system. Your computer normally boots using the operating system installed on your hard disk, but it can also be configured to use a ``bootable'' floppy disk. Most modern computers can also boot from a CDROM in the CDROM drive.

Tip: If you have FreeBSD on CDROM or DVD (either one you purchased or you prepared yourself), and your computer allows you to boot from the CDROM or DVD (typically a BIOS option called ``Boot Order'' or similar), then you can skip this section. The FreeBSD CDROM and DVD images are bootable and can be used to install FreeBSD without any other special preparation.

To create boot floppy images, follow these steps:

  1. Acquire the Boot Floppy Images

    The boot disks are available on your installation media in the floppies/ directory, and can also be downloaded from the floppies directory for the i386 architecture and from this floppies directory for the Alpha architecture.

    The floppy images have a .flp extension. The floppies/ directory contains a number of different images, and the ones you will need to use depends on the version of FreeBSD you are installing, and in some cases, the hardware you are installing to. In most cases you will just need two files, kern.flp and mfsroot.flp. Additional device drivers may be necessary for some systems. These drivers are provided on the drivers.flp image. Check README.TXT in the same directory for the most up to date information about these floppy images.

    Important: Your FTP program must use binary mode to download these disk images. Some web browsers have been known to use text (or ASCII) mode, which will be apparent if you cannot boot from the disks.

  2. Prepare the Floppy Disks

    You must prepare one floppy disk per image file you had to download. It is imperative that these disks are free from defects. The easiest way to test this is to format the disks for yourself. Do not trust pre-formatted floppies. The format utility in Windows will not tell about the presence of bad blocks, it simply marks them as ``bad'' and ignores them. It is advised that you use brand new floppies if choosing this installation route.

    Important: If you try to install FreeBSD and the installation program crashes, freezes, or otherwise misbehaves, one of the first things to suspect is the floppies. Try writing the floppy image files to new disks and try again.

  3. Write the Image Files to the Floppy Disks

    The .flp files are not regular files you copy to the disk. They are images of the complete contents of the disk. This means that you cannot simply copy files from one disk to another. Instead, you must use specific tools to write the images directly to the disk.

    If you are creating the floppies on a computer running MS-DOS/Windows, then we provide a tool to do this called fdimage.

    If you are using the floppies from the CDROM, and your CDROM is the E: drive, then you would run this:

    E:\> tools\fdimage floppies\kern.flp A:
    

    Repeat this command for each .flp file, replacing the floppy disk each time, being sure to label the disks with the name of the file that you copied to them. Adjust the command line as necessary, depending on where you have placed the .flp files. If you do not have the CDROM, then fdimage can be downloaded from the tools directory on the FreeBSD FTP site.

    If you are writing the floppies on a UNIX system (such as another FreeBSD system) you can use the dd(1) command to write the image files directly to disk. On FreeBSD, you would run:

    # dd if=kern.flp of=/dev/fd0
    

    On FreeBSD, /dev/fd0 refers to the first floppy disk (the A: drive). /dev/fd1 would be the B: drive, and so on. Other UNIX variants might have different names for the floppy disk devices, and you will need to check the documentation for the system as necessary.

You are now ready to start installing FreeBSD.


2.3 Starting the Installation

Important: By default, the installation will not make any changes to your disk(s) until you see the following message:

Last Chance: Are you SURE you want continue the installation?

If you're running this on a disk with data you wish to save then WE
STRONGLY ENCOURAGE YOU TO MAKE PROPER BACKUPS before proceeding!

We can take no responsibility for lost disk contents!

The install can be exited at any time prior to the final warning without changing the contents of the hard drive. If you are concerned that you have configured something incorrectly you can just turn the computer off before this point, and no damage will be done.


2.3.1 Booting

2.3.1.1 Booting for the i386

  1. Start with your computer turned off.

  2. Turn on the computer. As it starts it should display an option to enter the system set up menu, or BIOS, commonly reached by keys like F2, F10, Del, or Alt+S. Use whichever keystroke is indicated on screen. In some cases your computer may display a graphic while it starts. Typically, pressing Esc will dismiss the graphic and allow you to see the necessary messages.

  3. Find the setting that controls which devices the system boots from. This is usually labeled as the ``Boot Order'' and commonly shown as a list of devices, such as Floppy, CDROM, First Hard Disk, and so on.

    If you needed to prepare boot floppies, then make sure that the floppy disk is selected. If you are booting from the CDROM then make sure that that is selected instead. In case of doubt, you should consult the manual that came with your computer, and/or its motherboard.

    Make the change, then save and exit. The computer should now restart.

  4. If you needed to prepare boot floppies, as described in Section 2.2.7, then one of them will be the first boot disc, probably the one containing kern.flp. Put this disc in your floppy drive.

    If you are booting from CDROM, then you will need to turn on the computer, and insert the CDROM at the first opportunity.

    If your computer starts up as normal and loads your existing operating system, then either:

    1. The disks were not inserted early enough in the boot process. Leave them in, and try restarting your computer.

    2. The BIOS changes earlier did not work correctly. You should redo that step until you get the right option.

    3. Your particular BIOS does not support booting from the desired media.

  5. FreeBSD will start to boot. If you are booting from CDROM you will see a display similar to this (version information omitted):

    Verifying DMI Pool Data ........
    Boot from ATAPI CD-ROM :
     1. FD 2.88MB  System Type-(00)
    Uncompressing ... done
    
    BTX loader 1.00 BTX version is 1.01
    Console: internal video/keyboard
    BIOS drive A: is disk0
    BIOS drive B: is disk1
    BIOS drive C: is disk2
    BIOS drive D: is disk3
    BIOS 639kB/261120kB available memory
    
    FreeBSD/i386 bootstrap loader, Revision 0.8
    
    /kernel text=0x277391 data=0x3268c+0x332a8 |
    
    |
    Hit [Enter] to boot immediately, or any other key for command prompt.
    Booting [kernel] in 9 seconds... _
    

    If you are booting from floppy disc, you will see a display similar to this (version information omitted):

    Verifying DMI Pool Data ........ 
    
    BTX loader 1.00  BTX version is 1.01 
    Console: internal video/keyboard 
    BIOS drive A: is disk0 
    BIOS drive C: is disk1 
    BIOS 639kB/261120kB available memory 
    
    FreeBSD/i386 bootstrap loader, Revision 0.8 
    
    /kernel text=0x277391 data=0x3268c+0x332a8 |
    
    Please insert MFS root floppy and press enter:
    

    Follow these instructions by removing the kern.flp disc, insert the mfsroot.flp disc, and press Enter.

  6. Whether you booted from floppy or CDROM, the boot process will then get to this point:

    Hit [Enter] to boot immediately, or any other key for command prompt. 
    Booting [kernel] in 9 seconds... _
    

    Either wait ten seconds, or press Enter. This will then launch the kernel configuration menu.


2.3.1.2 Booting for the Alpha

  1. Start with your computer turned off.

  2. Turn on the computer and wait for a boot monitor prompt.

  3. If you needed to prepare boot floppies, as described in Section 2.2.7 then one of them will be the first boot disc, probably the one containing kern.flp. Put this disc in your floppy drive and type the following command to boot the disk (substituting the name of your floppy drive if necessary):

    >>>BOOT DVA0 -FLAGS '' -FILE ''
    

    If you are booting from CDROM, insert the CDROM into the drive and type the following command to start the installation (substituting the name of the appropriate CDROM drive if necessary):

    >>>BOOT DKA0 -FLAGS '' -FILE ''
    
  4. FreeBSD will start to boot. If you are booting from a floppy disc, at some point you will see the message:

    Please insert MFS root floppy and press enter:
    

    Follow these instructions by removing the kern.flp disc, insert the mfsroot.flp disc, and press Enter.

  5. Whether you booted from floppy or CDROM, the boot process will then get to this point:

    Hit [Enter] to boot immediately, or any other key for command prompt. 
    Booting [kernel] in 9 seconds... _
    

    Either wait ten seconds, or press Enter. This will then launch the kernel configuration menu.


2.3.2 Kernel Configuration

Note: From FreeBSD versions 5.0 and later, userconfig has been deprecated in favor of the new device.hints(5) method. For more information on device.hints(5) please visit Section 7.5

The kernel is the core of the operating system. It is responsible for many things, including access to all the devices you may have on your system, such as hard disks, network cards, sound cards, and so on. Each piece of hardware supported by the FreeBSD kernel has a driver associated with it. Each driver has a two or three letter name, such as sa for the SCSI sequential access driver, or sio for the Serial I/O driver (which manages COM ports).

When the kernel starts, each driver checks the system to see whether or not the hardware it supports exists on your system. If it does, then the driver configures the hardware and makes it available to the rest of the kernel.

This checking is commonly referred to as device probing. Unfortunately, it is not always possible to do this in a safe way. Some hardware drivers do not co-exist well, and probing for one piece of hardware can sometimes leave another in an inconsistent state. This is a basic limitation of the PC design.

Many older devices are called ISA devices--as opposed to PCI devices. The ISA specification requires each device to have some information hard coded into it, typically the Interrupt Request Line number (IRQ) and IO port address that the driver uses. This information is commonly set by using physical jumpers on the card, or by using a DOS based utility.

This was often a source of problems, because it was not possible to have two devices that shared the same IRQ or port address.

Newer devices follow the PCI specification, which does not require this, as the devices are supposed to cooperate with the BIOS, and are told which IRQ and IO port addresses to use.

If you have any ISA devices in your computer then FreeBSD's driver for that device will need to be configured with the IRQ and port address that you have set the card to. This is why carrying out an inventory of your hardware (see Section 2.2.1) can be useful.

Unfortunately, the default IRQs and memory ports used by some drivers clash. This is because some ISA devices are shipped with IRQs or memory ports that clash. The defaults in FreeBSD's drivers are deliberately set to mirror the manufacturer's defaults, so that, out of the box, as many devices as possible will work.

This is almost never an issue when running FreeBSD day-to-day. Your computer will not normally contain two pieces of hardware that clash, because one of them would not work (irrespective of the operating system you are using).

It becomes an issue when you are installing FreeBSD for the first time because the kernel used to carry out the install has to contain as many drivers as possible, so that many different hardware configurations can be supported. This means that some of those drivers will have conflicting configurations. The devices are probed in a strict order, and if you own a device that is probed late in the process, but conflicted with an earlier probe, then your hardware might not function or be probed correctly when you install FreeBSD.

Because of this, the first thing you have the opportunity to do when installing FreeBSD is look at the list of drivers that are configured into the kernel, and either disable some of them, if you do not own that device, or confirm (and alter) the driver's configuration if you do own the device but the defaults are wrong.

This probably sounds much more complicated than it actually is.

Figure 2-1 shows the first kernel configuration menu. We recommend that you choose the Start kernel configuration in full-screen visual mode option, as it presents the easiest interface for the new user.

Figure 2-1. Kernel Configuration Menu

The kernel configuration screen (Figure 2-2) is then divided into four sections:

  1. A collapsible list of all the drivers that are currently marked as ``active'', subdivided into groups such as Storage, and Network. Each driver is shown as a description, its two or three letter driver name, and the IRQ and memory port used by that driver. In addition, if an active driver conflicts with another active driver then CONF is shown next to the driver name. This section also shows the total number of conflicting drivers that are currently active.

  2. Drivers that have been marked inactive. They remain in the kernel, but they will not probe for their device when the kernel starts. These are subdivided into groups in the same way as the active driver list.

  3. More detail about the currently selected driver, including its IRQ and memory port address.

  4. Information about the keystrokes that are valid at this point in time.

Figure 2-2. The Kernel Device Configuration Visual Interface

Do not worry if any conflicts are listed, it is to be expected; all the drivers are enabled, and as has already been explained, some of them will conflict with one another.

You now have to work through the list of drivers, resolving the conflicts.

Resolving Driver Conflicts

  1. Press X. This will completely expand the list of drivers, so you can see all of them. You will need to use the arrow keys to scroll back and forth through the active driver list.

    Figure 2-3 shows the result of pressing X.

    Figure 2-3. Expanded Driver List

  2. Disable all the drivers for devices that you do not have. To disable a driver, highlight it with the arrow keys and press Del. The driver will be moved to the Inactive Drivers list.

    If you inadvertently disable a device that you need then press Tab to switch to the Inactive Drivers list, select the driver that you disabled, and press Enter to move it back to the active list.

    Warning: Do not disable sc0. This controls the screen, and you will need this unless you are installing over a serial cable.

    Warning: Only disable atkbd0 if you are using a USB keyboard. If you have a normal keyboard then you must keep atkbd0.

  3. If there are no conflicts listed then you can skip this step. Otherwise, the remaining conflicts need to be examined. If they do not have the indication of an ``allowed conflict'' in the message area, then either the IRQ/address for device probe will need to be changed, or the IRQ/address on the hardware will need to be changed.

    To change the driver's configuration for IRQ and IO port address, select the device and press Enter. The cursor will move to the third section of the screen, and you can change the values. You should enter the values for IRQ and port address that you discovered when you made your hardware inventory. Press Q to finish editing the device's configuration and return to the active driver list.

    If you are not sure what these figures should be then you can try using -1. Some FreeBSD drivers can safely probe the hardware to discover what the correct value should be, and a value of -1 configures them to do this.

    The procedure for changing the address on the hardware varies from device to device. For some devices you may need to physically remove the card from your computer and adjust jumper settings or DIP switches. Other cards may have come with a DOS floppy that contains the programs used to reconfigure the card. In any case, you should refer to the documentation that came with the device. This will obviously entail restarting your computer, so you will need to boot back into the FreeBSD installation routine when you have reconfigured the card.

  4. When all the conflicts have been resolved the screen will look similar to Figure 2-4.

    Figure 2-4. Driver Configuration With No Conflicts

    As you can see, the active driver list is now much smaller, with only drivers for the hardware that actually exists being listed.

    You can now save these changes, and move on to the next step of the install. Press Q to quit the device configuration interface. This message will appear:

    Save these parameters before exiting? ([Y]es/[N]o/[C]ancel)
    

    Answer Y to save the parameters to memory (it will be saved to disk if you finish the install) and the probing will start. After displaying the probe results in white on black text sysinstall will start and display its main menu (Figure 2-5).

    Figure 2-5. Sysinstall Main Menu


2.3.3 Reviewing the Device Probe Results

The last few hundred lines that have been displayed on screen are stored and can be reviewed.

To review the buffer, press Scroll Lock. This turns on scrolling in the display. You can then use the arrow keys, or PageUp and PageDown to view the results. Press Scroll Lock again to stop scrolling.

Do this now, to review the text that scrolled off the screen when the kernel was carrying out the device probes. You will see text similar to Figure 2-6, although the precise text will differ depending on the devices that you have in your computer.

Figure 2-6. Typical Device Probe Results

avail memory = 253050880 (247120K bytes) 
Preloaded elf kernel "kernel" at 0xc0817000.
Preloaded mfs_root "/mfsroot" at 0xc0817084.
md0: Preloaded image </mfsroot> 4423680 bytes at 0xc03ddcd4

md1: Malloc disk
Using $PIR table, 4 entries at 0xc00fde60
npx0: <math processor> on motherboard   
npx0: INT 16 interface   
pcib0: <Host to PCI bridge> on motherboard
pci0: <PCI bus> on pcib0
pcib1:<VIA 82C598MVP (Apollo MVP3) PCI-PCI (AGP) bridge> at device 1.0 on pci0
pci1: <PCI bus> on pcib1
pci1: <Matrox MGA G200 AGP graphics accelerator> at 0.0 irq 11
isab0: <VIA 82C586 PCI-ISA bridge> at device 7.0 on pci0
isa0: <iSA bus> on isab0
atapci0: <VIA 82C586 ATA33 controller> port 0xe000-0xe00f at device 7.1 on pci0
ata0: at 0x1f0 irq 14 on atapci0
ata1: at 0x170 irq 15 on atapci0
uhci0 <VIA 83C572 USB controller> port 0xe400-0xe41f irq 10 at device 7.2 on pci
0
usb0: <VIA 83572 USB controller> on uhci0
usb0: USB revision 1.0
uhub0: VIA UHCI root hub, class 9/0, rev 1.00/1.00, addr1
uhub0: 2 ports with 2 removable, self powered
pci0: <unknown card> (vendor=0x1106, dev=0x3040) at 7.3
dc0: <ADMtek AN985 10/100BaseTX> port 0xe800-0xe8ff mem 0xdb000000-0xeb0003ff ir
q 11 at device 8.0 on pci0
dc0: Ethernet address: 00:04:5a:74:6b:b5
miibus0: <MII bus> on dc0
ukphy0: <Generic IEEE 802.3u media interface> on miibus0
ukphy0: 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
ed0: <NE2000 PCI Ethernet (RealTek 8029)> port 0xec00-0xec1f irq 9 at device 10.
0 on pci0
ed0 address 52:54:05:de:73:1b, type NE2000 (16 bit)
isa0: too many dependant configs (8)
isa0: unexpected small tag 14
orm0: <Option ROM> at iomem 0xc0000-0xc7fff on isa0
fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq2 on isa0
fdc0: FIFO enabled, 8 bytes threshold
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
atkbd0: <AT Keyboard> flags 0x1 irq1 on atkbdc0
kbd0 at atkbd0
psm0: <PS/2 Mouse> irq 12 on atkbdc0
psm0: model Generic PS/@ mouse, device ID 0
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 16550A
sio1 at port 0x2f8-0x2ff irq 3 on isa0
sio1: type 16550A
ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
pppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
ppc0: FIFO with 16/16/15 bytes threshold
plip0: <PLIP network interface> on ppbus0
ad0: 8063MB <IBM-DHEA-38451> [16383/16/63] at ata0-master UDMA33
acd0: CD-RW <LITE-ON LTR-1210B> at ata1-slave PIO4
Mounting root from ufs:/dev/md0c
/stand/sysinstall running as init on vty0

Check the probe results carefully to make sure that FreeBSD found all the devices you expected. If a device was not found, then it will not be listed. If the device's driver required configuring with the IRQ and port address then you should check that you entered them correctly.

If you need to make changes to the UserConfig device probing, it is easy to exit the sysinstall program and start over again. It is also a good way to become more familiar with the process.

Figure 2-7. Select Sysinstall Exit

Use the arrow keys to select Exit Install from the Main Install Screen menu. The following message will display:

                      User Confirmation Requested 
         Are you sure you wish to exit? The system will reboot 
           (be sure to remove any floppies from the drives).

                            [ Yes ]    No

The install program will start again if the CDROM is left in the drive and [Yes] is selected.

If you are booting from floppies it will be necessary to remove the mfsroot.flp floppy and replace it with kern.flp before rebooting.


2.4 Introducing Sysinstall

The sysinstall utility is the installation application provided by the FreeBSD Project. It is console based and is divided into a number of menus and screens that you can use to configure and control the installation process.

The sysinstall menu system is controlled by the arrow keys, Enter, Space, and other keys. A detailed description of these keys and what they do is contained in sysinstall's usage information.

To review this information, ensure that the Usage entry is highlighted and that the [Select] button is selected, as shown in Figure 2-8, then press Enter.

The instructions for using the menu system will be displayed. After reviewing them, press Enter to return to the Main Menu.

Figure 2-8. Selecting Usage from Sysinstall Main Menu


2.4.1 Selecting the Documentation Menu

From the Main Menu, select Doc with the arrow keys and press Enter.

Figure 2-9. Selecting Documentation Menu

This will display the Documentation Menu.

Figure 2-10. Sysinstall Documentation Menu

It is important to read the documents provided.

To view a document, select it with the arrow keys and press Enter. When finished reading a document, pressing Enter will return to the Documentation Menu.

To return to the Main Installation Menu, select Exit with the arrow keys and press Enter.


2.4.2 Selecting the Keymap Menu

To change the keyboard mapping, use the arrow keys to select Keymap from the menu and press Enter. This is only required if you are using a non-standard or non-US keyboard.

Figure 2-11. Sysinstall Main Menu

A different keyboard mapping may be chosen by selecting the menu item using up/down arrow keys and pressing Space. Pressing Space again will unselect the item. When finished, choose the [ OK ] using the arrow keys and press Enter.

Only a partial list is shown in this screen representation. Selecting [ Cancel ] by pressing Tab will use the default keymap and return to the Main Install Menu.

Figure 2-12. Sysinstall Keymap Menu


2.4.3 Installation Options Screen

Select Options and press Enter.

Figure 2-13. Sysinstall Main Menu

Figure 2-14. Sysinstall Options

The default values are usually fine for most users and do not need to be changed. The release name will vary according to the version being installed.

The description of the selected item will appear at the bottom of the screen highlighted in blue. Notice that one of the options is Use Defaults to reset all values to startup defaults.

Press F1 to read the help screen about the various options.

Pressing Q will return to the Main Install menu.


2.4.4 Begin a Standard Installation

The Standard installation is the option recommended for those new to UNIX or FreeBSD. Use the arrow keys to select Standard and then press Enter to start the installation.

Figure 2-15. Begin Standard Installation


2.5 Allocating Disk Space

Your first task is to allocate disk space for FreeBSD, and label that space so that sysinstall can prepare it. In order to do this you need to know how FreeBSD expects to find information on the disk.


2.5.1 BIOS Drive Numbering

Before you install and configure FreeBSD on your system, there is an important subject that you should be aware of, especially if you have multiple hard drives.

In a PC running a BIOS-dependent operating system such as MS-DOS or Microsoft Windows, the BIOS is able to abstract the normal disk drive order, and the operating system goes along with the change. This allows the user to boot from a disk drive other than the so-called ``primary master''. This is especially convenient for some users who have found that the simplest and cheapest way to keep a system backup is to buy an identical second hard drive, and perform routine copies of the first drive to the second drive using Ghost® or XCOPY . Then, if the first drive fails, or is attacked by a virus, or is scribbled upon by an operating system defect, he can easily recover by instructing the BIOS to logically swap the drives. It is like switching the cables on the drives, but without having to open the case.

More expensive systems with SCSI controllers often include BIOS extensions which allow the SCSI drives to be re-ordered in a similar fashion for up to seven drives.

A user who is accustomed to taking advantage of these features may become surprised when the results with FreeBSD are not as expected. FreeBSD does not use the BIOS, and does not know the ``logical BIOS drive mapping''. This can lead to very perplexing situations, especially when drives are physically identical in geometry, and have also been made as data clones of one another.

When using FreeBSD, always restore the BIOS to natural drive numbering before installing FreeBSD, and then leave it that way. If you need to switch drives around, then do so, but do it the hard way, and open the case and move the jumpers and cables.


2.5.2 Creating Slices Using FDisk

Note: No changes you make at this point will be written to the disk. If you think you have made a mistake and want to start again you can use the menus to exit sysinstall and try again or press U to use the Undo option. If you get confused and can not see how to exit you can always turn your computer off.

After choosing to begin a standard installation in sysinstall you will be shown this message:

                                 Message
 In the next menu, you will need to set up a DOS-style ("fdisk")
 partitioning scheme for your hard disk. If you simply wish to devote
 all disk space to FreeBSD (overwriting anything else that might be on
 the disk(s) selected) then use the (A)ll command to select the default
 partitioning scheme followed by a (Q)uit. If you wish to allocate only
 free space to FreeBSD, move to a partition marked "unused" and use the
 (C)reate command. 
                                [  OK  ] 

                      [ Press enter or space ]

Press Enter as instructed. You will then be shown a list of all the hard drives that the kernel found when it carried out the device probes. Figure 2-16 shows an example from a system with two IDE disks. They have been called ad0 and ad2.

Figure 2-16. Select Drive for FDisk

You might be wondering why ad1 is not listed here. Why has it been missed?

Consider what would happen if you had two IDE hard disks, one as the master on the first IDE controller, and one as the master on the second IDE controller. If FreeBSD numbered these as it found them, as ad0 and ad1 then everything would work.

But if you then added a third disk, as the slave device on the first IDE controller, it would now be ad1, and the previous ad1 would become ad2. Because device names (such as ad1s1a) are used to find filesystems, you may suddenly discover that some of your filesystems no longer appear correctly, and you would need to change your FreeBSD configuration.

To work around this, the kernel can be configured to name IDE disks based on where they are, and not the order in which they were found. With this scheme the master disk on the second IDE controller will always be ad2, even if there are no ad0 or ad1 devices.

This configuration is the default for the FreeBSD kernel, which is why this display shows ad0 and ad2. The machine on which this screenshot was taken had IDE disks on both master channels of the IDE controllers, and no disks on the slave channels.

You should select the disk on which you want to install FreeBSD, and then press [ OK ]. FDisk will start, with a display similar to that shown in Figure 2-17.

The FDisk display is broken into three sections.

The first section, covering the first two lines of the display, shows details about the currently selected disk, including its FreeBSD name, the disk geometry, and the total size of the disk.

The second section shows the slices that are currently on the disk, where they start and end, how large they are, the name FreeBSD gives them, and their description and sub-type. This example shows two small unused slices, which are artifacts of disk layout schemes on the PC. It also shows one large FAT slice, which almost certainly appears as C: in MS-DOS / Windows, and an extended slice, which may contain other drive letters for MS-DOS / Windows.

The third section shows the commands that are available in FDisk.

Figure 2-17. Typical Fdisk Partitions before Editing

What you do now will depend on how you want to slice up your disk.

If you want to use FreeBSD for the entire disk (which will delete all the other data on this disk when you confirm that you want sysinstall to continue later in the installation process) then you can press A, which corresponds to the Use Entire Disk option. The existing slices will be removed, and replaced with a small area flagged as unused (again, an artifact of PC disk layout), and then one large slice for FreeBSD. If you do this, then you should select the newly created FreeBSD slice using the arrow keys, and press S to mark the slice as being bootable. The screen will then look very similar to Figure 2-18. Note the A in the Flags column, which indicates that this slice is active, and will be booted from.

If you will be deleting an existing slice to make space for FreeBSD then you should select the slice using the arrow keys, and then press D. You can then press C, and be prompted for size of slice you want to create. Enter the appropriate figure and press Enter. The default value in this box represents the largest possible slice you can make, which could be the largest contiguous block of unallocated space or the size of the entire hard disk.

If you have already made space for FreeBSD (perhaps by using a tool such as PartitionMagic) then you can press C to create a new slice. Again, you will be prompted for the size of slice you would like to create.

Figure 2-18. Fdisk Partition Using Entire Disk

When finished, press Q. Your changes will be saved in sysinstall, but will not yet be written to disk.


2.5.3 Install a Boot Manager

You now have the option to install a boot manager. In general, you should choose to install the FreeBSD boot manager if:

  • You have more than one drive, and have installed FreeBSD onto a drive other than the first one.

  • You have installed FreeBSD alongside another operating system on the same disk, and you want to choose whether to start FreeBSD or the other operating system when you start the computer.

If FreeBSD is going to be the only operating system on this machine, installed on the first hard disk, then the Standard boot manager will suffice. Choose None if you are using a third-party boot manager capable of booting FreeBSD.

Make your choice and press Enter.

Figure 2-19. Sysinstall Boot Manager Menu

The help screen, reached by pressing F1, discusses the problems that can be encountered when trying to share the hard disk between operating systems.


2.5.4 Creating Slices on Another Drive

If there is more than one drive, it will return to the Select Drives screen after the boot manager selection. If you wish to install FreeBSD on to more than one disk, then you can select another disk here and repeat the slice process using FDisk.

Important: If you are installing FreeBSD on a drive other than your first, then the FreeBSD boot manager needs to be installed on both drives.

Figure 2-20. Exit Select Drive

The Tab key toggles between the last drive selected, [ OK ], and [ Cancel ].

Press the Tab once to toggle to the [ OK ], then press Enter to continue with the installation.


2.5.5 Creating Partitions Using Disklabel

You must now create some partitions inside each slice that you have just created. Remember that each partition is lettered, from a through to h, and that partitions b, c, and d have conventional meanings that you should adhere to.

Certain applications can benefit from particular partition schemes, especially if you are laying out partitions across more than one disk. However, for this, your first FreeBSD installation, you do not need to give too much thought to how you partition the disk. It is more important that you install FreeBSD and start learning how to use it. You can always re-install FreeBSD to change your partition scheme when you are more familiar with the operating system.

This scheme features four partitions--one for swap space, and three for filesystems.

Table 2-2. Partition Layout for First Disk

Partition Filesystem Size Description
a / 100 MB This is the root filesystem. Every other filesystem will be mounted somewhere under this one. 100 MB is a reasonable size for this filesystem. You will not be storing too much data on it, as a regular FreeBSD install will put about 40 MB of data here. The remaining space is for temporary data, and also leaves expansion space if future versions of FreeBSD need more space in /.
b N/A 2-3 x RAM

The system's swap space is kept on this partition. Choosing the right amount of swap space can be a bit of an art. A good rule of thumb is that your swap space should be two or three times as much as the available physical memory (RAM). You should also have at least 64 MB of swap, so if you have less than 32 MB of RAM in your computer then set the swap amount to 64 MB.

If you have more than one disk then you can put swap space on each disk. FreeBSD will then use each disk for swap, which effectively speeds up the act of swapping. In this case, calculate the total amount of swap you need (e.g., 128 MB), and then divide this by the number of disks you have (e.g., two disks) to give the amount of swap you should put on each disk, in this example, 64 MB of swap per disk.

e /var 50 MB The /var directory contains files that are constantly varying; log files, and other administrative files. Many of these files are read-from or written-to extensively during FreeBSD's day-to-day running. Putting these files on another filesystem allows FreeBSD to optimize the access of these files without affecting other files in other directories that do not have the same access pattern.
f /usr Rest of disk All your other files will typically be stored in /usr and its subdirectories.

If you will be installing FreeBSD on to more than one disk then you must also create partitions in the other slices that you configured. The easiest way to do this is to create two partitions on each disk, one for the swap space, and one for a filesystem.

Table 2-3. Partition Layout for Subsequent Disks

Partition Filesystem Size Description
b N/A See description As already discussed, you can split swap space across each disk. Even though the a partition is free, convention dictates that swap space stays on the b partition.
e /diskn Rest of disk The rest of the disk is taken up with one big partition. This could easily be put on the a partition, instead of the e partition. However, convention says that the a partition on a slice is reserved for the filesystem that will be the root (/) filesystem. You do not have to follow this convention, but sysinstall does, so following it yourself makes the installation slightly cleaner. You can choose to mount this filesystem anywhere; this example suggests that you mount them as directories /diskn, where n is a number that changes for each disk. But you can use another scheme if you prefer.

Having chosen your partition layout you can now create it using sysinstall. You will see this message:

                                 Message
 Now, you need to create BSD partitions inside of the fdisk
 partition(s) just created. If you have a reasonable amount of disk
 space (200MB or more) and don't have any special requirements, simply
 use the (A)uto command to allocate space automatically. If you have
 more specific needs or just don't care for the layout chosen by
 (A)uto, press F1 for more information on manual layout.  

                                [  OK  ]
                          [ Press enter or space ]

Press Enter to start the FreeBSD partition editor, called Disklabel.

Figure 2-21 shows the display when you first start Disklabel. The display is divided in to three sections.

The first few lines show the name of the disk you are currently working on, and the slice that contains the partitions you are creating (at this point Disklabel calls this the Partition name rather than slice name). This display also shows the amount of free space within the slice; that is, space that was set aside in the slice, but that has not yet been assigned to a partition.

The middle of the display shows the partitions that have been created, the name of the filesystem that each partition contains, their size, and some options pertaining to the creation of the filesystem.

The bottom third of the screen shows the keystrokes that are valid in Disklabel.

Figure 2-21. Sysinstall Disklabel Editor

Disklabel can automatically create partitions for you and assign them default sizes. Try this now, by Pressing A. You will see a display similar to that shown in Figure 2-22. Depending on the size of the disk you are using, the defaults may or may not be appropriate. This does not matter, as you do not have to accept the defaults.

Note: Beginning with FreeBSD 4.5, the default partitioning assigns the /tmp directory its own partition instead of being part of the / partition. This helps avoid filling the / partition with temporary files.

Figure 2-22. Sysinstall Disklabel Editor with Auto Defaults

If you choose to not use the default partitions and wish to replace them with your own, use the arrow keys to select the first partition, and press D to delete it. Repeat this to delete all the suggested partitions.

To create the first partition (a, mounted as / -- root), make sure the proper disk slice at the top of the screen is selected and press C. A dialog box will appear prompting you for the size of the new partition (as shown in Figure 2-23). You can enter the size as the number of disk blocks you want to use, or as a number followed by either M for megabytes, G for gigabytes, or C for cylinders.

Note: Beginning with FreeBSD 5.X, users can: select UFS2 using the Custom Newfs (Z) option, create labels with Auto Defaults and modify them with the Custom Newfs option or add -O 2 during the regular creation period. Do not forget to add -U for SoftUpdates if you use the Custom Newfs option!

Figure 2-23. Free Space for Root Partition

The default size shown will create a partition that takes up the rest of the slice. If you are using the partition sizes described in the earlier example, then delete the existing figure using Backspace, and then type in 64M, as shown in Figure 2-24. Then press [ OK ].

Figure 2-24. Edit Root Partition Size

Having chosen the partition's size you will then be asked whether this partition will contain a filesystem or swap space. The dialog box is shown in Figure 2-25. This first partition will contain a filesystem, so check that FS is selected and press Enter.

Figure 2-25. Choose the Root Partition Type

Finally, because you are creating a filesystem, you must tell Disklabel where the filesystem is to be mounted. The dialog box is shown in Figure 2-26. The root filesystem's mount point is /, so type /, and then press Enter.

Figure 2-26. Choose the Root Mount Point

The display will then update to show you the newly created partition. You should repeat this procedure for the other partitions. When you create the swap partition, you will not be prompted for the filesystem mount point, as swap partitions are never mounted. When you create the final partition, /usr, you can leave the suggested size as is, to use the rest of the slice.

Your final FreeBSD DiskLabel Editor screen will appear similar to Figure 2-27, although your values chosen may be different. Press Q to finish.

Figure 2-27. Sysinstall Disklabel Editor


2.6 Choosing What to Install

2.6.1 Select the Distribution Set

Deciding which distribution set to install will depend largely on the intended use of the system and the amount of disk space available. The predefined options range from installing the smallest possible configuration to everything. Those who are new to UNIX and/or FreeBSD should almost certainly select one of these canned options. Customizing a distribution set is typically for the more experienced user.

Press F1 for more information on the distribution set options and what they contain. When finished reviewing the help, pressing Enter will return to the Select Distributions Menu.

If a graphical user interface is desired then a distribution set that is preceded by an X should be chosen. The configuration of XFree86 and selection of a default desktop is part of the post-installation steps.

The default version of XFree86 that is installed depends on the version of the FreeBSD that you are installing. For FreeBSD versions prior to 4.6, XFree86 3.X is installed. For FreeBSD 4.6 and later, XFree86 4.X is the default.

You should check to see whether your video card is supported at the XFree86 web site. If your video card is not supported under the default version that FreeBSD will install, you should select a distribution without X for installation. After installation, install and configure the appropriate version of XFree86 using the ports collection.

If compiling a custom kernel is anticipated, select an option which includes the source code. For more information on why a custom kernel should be built or how to build a custom kernel, see Chapter 9.

Obviously, the most versatile system is one that includes everything. If there is adequate disk space, select All as shown in Figure 2-28 by using the arrow keys and press Enter. If there is a concern about disk space consider using an option that is more suitable for the situation. Do not fret over the perfect choice, as other distributions can be added after installation.

Figure 2-28. Choose Distributions


2.6.2 Installing the Ports Collection

After selecting the desired distribution, an opportunity to install the FreeBSD Ports Collection is presented. The ports collection is an easy and convenient way to install software. The ports collection does not contain the source code necessary to compile the software. Instead, it is a collection of files which automates the downloading, compiling and installation of third-party software packages. Chapter 4 discusses how to use the ports collection.

The installation program does not check to see if you have adequate space. Select this option only if you have adequate hard disk space. As of FreeBSD 5.2.1, the FreeBSD Ports Collection takes up about 300 MB of disk space. You can safely assume a larger value for more recent versions of FreeBSD.

                         User Confirmation Requested
 Would you like to install the FreeBSD ports collection? 

 This will give you ready access to over 10,000 ported software packages,
 at a cost of around 300 MB of disk space when "clean" and possibly much
 more than that if a lot of the distribution tarballs are loaded
 (unless you have the extra CDs from a FreeBSD CD/DVD distribution
 available and can mount it on /cdrom, in which case this is far less
 of a problem). 

 The ports collection is a very valuable resource and well worth having
 on your /usr partition, so it is advisable to say Yes to this option. 

 For more information on the ports collection & the latest ports,
 visit: 
     http://www.FreeBSD.org/ports  

                              [ Yes ]     No

Select [ Yes ] with the arrow keys to install the ports collection or [ No ] to skip this option. Press Enter to continue. The Choose Distributions menu will redisplay.

Figure 2-29. Confirm Distributions

If satisfied with the options, select Exit with the arrow keys, ensure that [ OK ] is highlighted, and pressing Enter to continue.


2.7 Choosing Your Installation Media

If Installing from a CDROM or DVD, use the arrow keys to highlight Install from a FreeBSD CD/DVD. Ensure that [ OK ] is highlighted, then press Enter to proceed with the installation.

For other methods of installation, select the appropriate option and follow the instructions.

Press F1 to display the Online Help for installation media. Press Enter to return to the media selection menu.

Figure 2-30. Choose Installation Media

FTP Installation Modes: There are three FTP installation modes you can choose from: active FTP, passive FTP, or via a HTTP proxy.

FTP Active: Install from an FTP server

This option will make all FTP transfers use ``Active'' mode. This will not work through firewalls, but will often work with older FTP servers that do not support passive mode. If your connection hangs with passive mode (the default), try active!

FTP Passive: Install from an FTP server through a firewall

This option instructs sysinstall to use ``Passive'' mode for all FTP operations. This allows the user to pass through firewalls that do not allow incoming connections on random TCP ports.

FTP via a HTTP proxy: Install from an FTP server through a http proxy

This option instructs sysinstall to use the HTTP protocol (like a web browser) to connect to a proxy for all FTP operations. The proxy will translate the requests and send them to the FTP server. This allows the user to pass through firewalls that do not allow FTP at all, but offer a HTTP proxy. In this case, you have to specify the proxy in addition to the FTP server.

For a proxy FTP server, you should usually give the name of the server you really want as a part of the username, after an ``@'' sign. The proxy server then ``fakes'' the real server. For example, assuming you want to install from ftp.FreeBSD.org, using the proxy FTP server foo.example.com, listening on port 1024.

In this case, you go to the options menu, set the FTP username to ftp@ftp.FreeBSD.org, and the password to your email address. As your installation media, you specify FTP (or passive FTP, if the proxy supports it), and the URL ftp://foo.example.com:1234/pub/FreeBSD.

Since /pub/FreeBSD from ftp.FreeBSD.org is proxied under foo.example.com, you are able to install from that machine (which will fetch the files from ftp.FreeBSD.org as your installation requests them).


2.8 Committing to the Installation

The installation can now proceed if desired. This is also the last chance for aborting the installation to prevent changes to the hard drive.

                       User Confirmation Requested
 Last Chance! Are you SURE you want to continue the installation? 

 If you're running this on a disk with data you wish to save then WE
 STRONGLY ENCOURAGE YOU TO MAKE PROPER BACKUPS before proceeding! 

 We can take no responsibility for lost disk contents!  

                             [ Yes ]    No

Select [ Yes ] and press Enter to proceed.

The installation time will vary according to the distribution chosen, installation media, and the speed of the computer. There will be a series of messages displayed indicating the status.

The installation is complete when the following message is displayed:

                               Message 

Congratulations! You now have FreeBSD installed on your system. 

We will now move on to the final configuration questions. 
For any option you do not wish to configure, simply select No. 

If you wish to re-enter this utility after the system is up, you may
do so by typing: /stand/sysinstall .  

                                 [ OK ] 

                      [  Press enter to continue  ]

Press Enter to proceed with post-installation configurations.

Selecting [ No ] and pressing Enter will abort the installation so no changes will be made to your system. The following message will appear:

                                Message
Installation complete with some errors.  You may wish to scroll
through the debugging messages on VTY1 with the scroll-lock feature. 
You can also choose "No" at the next prompt and go back into the
installation menus to retry whichever operations have failed. 

                                 [ OK ]

This message is generated because nothing was installed. Pressing Enter will return to the Main Installation Menu to exit the installation.


2.9 Post-installation

Configuration of various options follows the successful installation. An option can be configured by re-entering the configuration options before booting the new FreeBSD system or after installation using /stand/sysinstall and selecting Configure.


2.9.1 Network Device Configuration

If you previously configured PPP for an FTP install, this screen will not display and can be configured later as described above.

For detailed information on Local Area Networks and configuring FreeBSD as a gateway/router refer to the Advanced Networking chapter.

                      User Confirmation Requested 
   Would you like to configure any Ethernet or SLIP/PPP network devices?

                             [ Yes ]   No

To configure a network device, select [ Yes ] and press Enter. Otherwise, select [ No ] to continue.

Figure 2-31. Selecting an Ethernet Device

Select the interface to be configured with the arrow keys and press Enter.

                      User Confirmation Requested 
       Do you want to try IPv6 configuration of the interface?

                              Yes   [ No ]

In this private local area network, the current Internet type protocol (IPv4) was sufficient and [ No ] was selected with the arrow keys and Enter pressed.

If you are connected to an existing IPv6 network with an RA server, then choose [ Yes ] and press Enter. It will take several seconds to scan for RA servers.

                             User Confirmation Requested 
        Do you want to try DHCP configuration of the interface?

                              Yes   [ No ]

If DHCP (Dynamic Host Configuration Protocol) is not required select [ No ] with the arrow keys and press Enter.

Selecting [ Yes ] will execute dhclient, and if successful, will fill in the network configuration information automatically. Refer to Section 19.10 for more information.

The following Network Configuration screen shows the configuration of the Ethernet device for a system that will act as the gateway for a Local Area Network.

Figure 2-32. Set Network Configuration for ed0

Use Tab to select the information fields and fill in appropriate information:

Host

The fully-qualified hostname, such as k6-2.example.com in this case.

Domain

The name of the domain that your machine is in, such as example.com for this case.

IPv4 Gateway

IP address of host forwarding packets to non-local destinations. You must fill this in if the machine is a node on the network. Leave this field blank if the machine is the gateway to the Internet for the network. The IPv4 Gateway is also known as the default gateway or default route.

Name server

IP address of your local DNS server. There is no local DNS server on this private local area network so the IP address of the provider's DNS server (208.163.10.2) was used.

IPv4 address

The IP address to be used for this interface was 192.168.0.1

Netmask

The address block being used for this local area network is a Class C block (192.168.0.0 - 192.168.255.255). The default netmask is for a Class C network (255.255.255.0).

Extra options to ifconfig

Any interface-specific options to ifconfig you would like to add. There were none in this case.

Use Tab to select [ OK ] when finished and press Enter.

                      User Confirmation Requested 
        Would you like to Bring Up the ed0 interface right now?

                             [ Yes ]   No

Choosing [ Yes ] and pressing Enter will bring the machine up on the network and be ready for use. However, this does not accomplish much during installation, since the machine still needs to be rebooted.


2.9.2 Configure Gateway

                       User Confirmation Requested 
       Do you want this machine to function as a network gateway?

                              [ Yes ]    No

If the machine will be acting as the gateway for a local area network and forwarding packets between other machines then select [ Yes ] and press Enter. If the machine is a node on a network then select [ No ] and press Enter to continue.


2.9.3 Configure Internet Services

                      User Confirmation Requested
Do you want to configure inetd and the network services that it provides?

                               Yes   [ No ]

If [ No ] is selected, various services such telnetd will not be enabled. This means that remote users will not be able to telnet into this machine. Local users will be still be able to access remote machines with telnet.

These services can be enabled after installation by editing /etc/inetd.conf with your favorite text editor. See Section 19.14.1 for more information.

Select [ Yes ] if you wish to configure these services during install. An additional confirmation will display:

                      User Confirmation Requested
The Internet Super Server (inetd) allows a number of simple Internet
services to be enabled, including finger, ftp and telnetd.  Enabling
these services may increase risk of security problems by increasing
the exposure of your system.

With this in mind, do you wish to enable inetd?

                             [ Yes ]   No

Select [ Yes ] to continue.

                      User Confirmation Requested
inetd(8) relies on its configuration file, /etc/inetd.conf, to determine
which of its Internet services will be available.  The default FreeBSD
inetd.conf(5) leaves all services disabled by default, so they must be
specifically enabled in the configuration file before they will
function, even once inetd(8) is enabled.  Note that services for
IPv6 must be separately enabled from IPv4 services.

Select [Yes] now to invoke an editor on /etc/inetd.conf, or [No] to
use the current settings.

                             [ Yes ]   No

Selecting [ Yes ] will allow adding services by deleting the # at the beginning of a line.

Figure 2-33. Editing inetd.conf

After adding the desired services, pressing Esc will display a menu which will allow exiting and saving the changes.


2.9.4 Anonymous FTP

                      User Confirmation Requested
 Do you want to have anonymous FTP access to this machine? 

                              Yes    [ No ]

2.9.4.1 Deny Anonymous FTP

Selecting the default [ No ] and pressing Enter will still allow users who have accounts with passwords to use FTP to access the machine.


2.9.4.2 Allow Anonymous FTP

Anyone can access your machine if you elect to allow anonymous FTP connections. The security implications should be considered before enabling this option. For more information about security see Chapter 10.

To allow anonymous FTP, use the arrow keys to select [ Yes ] and press Enter. The following screen (or similar) will display:

Figure 2-34. Default Anonymous FTP Configuration

Pressing F1 will display the help:

This screen allows you to configure the anonymous FTP user.

The following configuration values are editable:

UID:     The user ID you wish to assign to the anonymous FTP user.
         All files uploaded will be owned by this ID.

Group:   Which group you wish the anonymous FTP user to be in.

Comment: String describing this user in /etc/passwd


FTP Root Directory:

        Where files available for anonymous FTP will be kept.

Upload subdirectory:

        Where files uploaded by anonymous FTP users will go.

The ftp root directory will be put in /var by default. If you do not have enough room there for the anticipated FTP needs, the /usr directory could be used by setting the FTP Root Directory to /usr/ftp.

When you are satisfied with the values, press Enter to continue.

                          User Confirmation Requested 
         Create a welcome message file for anonymous FTP users?

                              [ Yes ]    No

If you select [ Yes ] and press Enter, an editor will automatically start allowing you to edit the message.

Figure 2-35. Edit the FTP Welcome Message

This is a text editor called ee. Use the instructions to change the message or change the message later using a text editor of your choice. Note the file name/location at the bottom of the editor screen.

Press Esc and a pop-up menu will default to a) leave editor. Press Enter to exit and continue. Press Enter again to save changes if you made any.


2.9.5 Configure Network File System

Network File System (NFS) allows sharing of files across a network. A machine can be configured as a server, a client, or both. Refer to Section 19.6 for a more information.


2.9.5.1 NFS Server

                       User Confirmation Requested
 Do you want to configure this machine as an NFS server? 

                              Yes    [ No ]

If there is no need for a Network File System server, select [ No ] and press Enter.

If [ Yes ] is chosen, a message will pop-up indicating that the exports file must be created.

                               Message
Operating as an NFS server means that you must first configure an
/etc/exports file to indicate which hosts are allowed certain kinds of
access to your local filesystems.
Press [Enter] now to invoke an editor on /etc/exports
                               [ OK ]

Press Enter to continue. A text editor will start allowing the exports file to be created and edited.

Figure 2-36. Editing exports

Use the instructions to add the actual exported filesystems now or later using a text editor of your choice. Note the file name/location at the bottom of the editor screen.

Press Esc and a pop-up menu will default to a) leave editor. Press Enter to exit and continue.


2.9.5.2 NFS Client

The NFS client allows your machine to access NFS servers.

                       User Confirmation Requested
 Do you want to configure this machine as an NFS client? 

                              Yes   [ No ]

With the arrow keys, select [ Yes ] or [ No ] as appropriate and press Enter.


2.9.6 Security Profile

A ``security profile'' is a set of configuration options that attempts to achieve the desired ratio of security to convenience by enabling and disabling certain programs and other settings. The more severe the security profile, the fewer programs will be enabled by default. This is one of the basic principles of security: do not run anything except what you must.

Please note that the security profile is just a default setting. All programs can be enabled and disabled after you have installed FreeBSD by editing or adding the appropriate line(s) to /etc/rc.conf. For more information, please see the rc.conf(5) manual page.

The following table describes what each of the security profiles does. The columns are the choices you have for a security profile, and the rows are the program or feature that the profile enables or disables.

Table 2-4. Possible Security Profiles

  Extreme Moderate
sendmail(8) NO YES
sshd(8) NO YES
portmap(8) NO MAYBE [a]
NFS server NO YES
securelevel(8) YES [b] NO
Notes:
a. The portmapper is enabled if the machine has been configured as an NFS client or server earlier in the installation.
b. If you choose a security profile that sets the securelevel to ``Extreme'' or ``High'', you must be aware of the implications. Please read the init(8) manual page and pay particular attention to the meanings of the security levels, or you may have significant trouble later!
                       User Confirmation Requested
 Do you want to select a default security profile for this host (select
 No for "medium" security)? 

                            [ Yes ]    No

Selecting [ No ] and pressing Enter will set the security profile to medium.

Selecting [ Yes ] and pressing Enter will allow selecting a different security profile.

Figure 2-37. Security Profile Options

Press F1 to display the help. Press Enter to return to selection menu.

Use the arrow keys to choose Medium unless your are sure that another level is required for your needs. With [ OK ] highlighted, press Enter.

An appropriate confirmation message will display depending on which security setting was chosen.

                                 Message

Moderate security settings have been selected.

Sendmail and SSHd have been enabled, securelevels are
disabled, and NFS server setting have been left intact.
PLEASE NOTE that this still does not save you from having
to properly secure your system in other ways or exercise
due diligence in your administration, this simply picks
a standard set of out-of-box defaults to start with.

To change any of these settings later, edit /etc/rc.conf

                                  [OK]
                                 Message

Extreme security settings have been selected.

Sendmail, SSHd, and NFS services have been disabled, and
securelevels have been enabled.
PLEASE NOTE that this still does not save you from having
to properly secure your system in other ways or exercise
due diligence in your administration, this simply picks
a more secure set of out-of-box defaults to start with.

To change any of these settings later, edit /etc/rc.conf

                                  [OK]

Press Enter to continue with the post-installation configuration.

Warning: The security profile is not a silver bullet! Even if you use the extreme setting, you need to keep up with security issues by reading an appropriate mailing list, using good passwords and passphrases, and generally adhering to good security practices. It simply sets up the desired security to convenience ratio out of the box.


2.9.7 System Console Settings

There are several options available to customize the system console.

                      User Confirmation Requested 
       Would you like to customize your system console settings?

                              [ Yes ]  No

To view and configure the options, select [ Yes ] and press Enter.

Figure 2-38. System Console Configuration Options

A commonly used option is the screen saver. Use the arrow keys to select Saver and then press Enter.

Figure 2-39. Screen Saver Options

Select the desired screen saver using the arrow keys and then press Enter. The System Console Configuration menu will redisplay.

The default time interval is 300 seconds. To change the time interval, select Saver again. At the Screen Saver Options menu, select Timeout using the arrow keys and press Enter. A pop-up menu will appear:

Figure 2-40. Screen Saver Timeout

The value can be changed, then select [ OK ] and press Enter to return to the System Console Configuration menu.

Figure 2-41. System Console Configuration Exit

Selecting Exit and pressing Enter will continue with the post-installation configurations.


2.9.8 Setting the Time Zone

Setting the time zone for your machine will allow it to automatically correct for any regional time changes and perform other time zone related functions properly.

The example shown is for a machine located in the Eastern time zone of the United States. Your selections will vary according to your geographical location.

                      User Confirmation Requested 
          Would you like to set this machine's time zone now?

                            [ Yes ]   No

Select [ Yes ] and press Enter to set the time zone.

                       User Confirmation Requested
 Is this machine's CMOS clock set to UTC? If it is set to local time
 or you don't know, please choose NO here! 

                              Yes   [ No ]

Select [ Yes ] or [ No ] according to how the machine's clock is configured and press Enter.

Figure 2-42. Select Your Region

The appropriate region is selected using the arrow keys and then pressing Enter.

Figure 2-43. Select Your Country

Select the appropriate country using the arrow keys and press Enter.

Figure 2-44. Select Your Time Zone

The appropriate time zone is selected using the arrow keys and pressing Enter.

                            Confirmation 
            Does the abbreviation 'EDT' look reasonable?

                            [ Yes ]   No

Confirm the abbreviation for the time zone is correct. If it looks okay, press Enter to continue with the post-installation configuration.


2.9.9 Linux Compatibility

                      User Confirmation Requested 
          Would you like to enable Linux binary compatibility?

                            [ Yes ]   No

Selecting [ Yes ] and pressing Enter will allow running Linux software on FreeBSD. The install will add the appropriate packages for Linux compatibility.

If installing by FTP, the machine will need to be connected to the Internet. Sometimes a remote ftp site will not have all the distributions like the Linux binary compatibility. This can be installed later if necessary.


2.9.10 Mouse Settings

This option will allow you to cut and paste text in the console and user programs with a 3-button mouse. If using a 2-button mouse, refer to manual page, moused(8), after installation for details on emulating the 3-button style. This example depicts a non-USB mouse configuration (such as a PS/2 or COM port mouse):

                      User Confirmation Requested 
         Does this system have a non-USB mouse attached to it?

                            [ Yes ]    No

Select [ Yes ] for a non-USB mouse or [ No ] for a USB mouse and press Enter.

Figure 2-45. Select Mouse Protocol Type

Use the arrow keys to select Type and press Enter.

Figure 2-46. Set Mouse Protocol

The mouse used in this example is a PS/2 type, so the default Auto was appropriate. To change protocol, use the arrow keys to select another option. Ensure that [ OK ] is highlighted and press Enter to exit this menu.

Figure 2-47. Configure Mouse Port

Use the arrow keys to select Port and press Enter.

Figure 2-48. Setting the Mouse Port

This system had a PS/2 mouse, so the default PS/2 was appropriate. To change the port, use the arrow keys and then press Enter.

Figure 2-49. Enable the Mouse Daemon

Last, use the arrow keys to select Enable, and press Enter to enable and test the mouse daemon.

Figure 2-50. Test the Mouse Daemon

Move the mouse around the screen and verify the cursor shown responds properly. If it does, select [ Yes ] and press Enter. If not, the mouse has not been configured correctly -- select [ No ] and try using different configuration options.

Select Exit with the arrow keys and press Enter to return to continue with the post-installation configuration.


2.9.11 Configure Additional Network Services

Configuring network services can be a daunting task for new users if they lack previous knowledge in this area. Networking, including the Internet, is critical to all modern operating systems including FreeBSD; as a result, it is very useful to have some understanding FreeBSD's extensive networking capabilities. Doing this during the installation will ensure users have some understanding of the various services available to them.

Network services are programs that accept input from anywhere on the network. Every effort is made to make sure these programs will not do anything ``harmful''. Unfortunately, programmers are not perfect and through time there have been cases where bugs in network services have been exploited by attackers to do bad things. It is important that you only enable the network services you know that you need. If in doubt it is best if you do not enable a network service until you find out that you do need it. You can always enable it later by re-running sysinstall or by using the features provided by the /etc/rc.conf file.

Selecting the Networking option will display a menu similar to the one below:

Figure 2-51. Network Configuration Upper-level

The first option, Interfaces, was previously covered during the Section 2.9.1, thus this option can safely be ignored.

Selecting the AMD option adds support for the BSD automatic mount utility. This is usually used in conjunction with the NFS protocol (see below) for automatically mounting remote file systems. No special configuration is required here.

Next in line is the AMD Flags option. When selected, a menu will pop up for you to enter specific AMD flags. The menu already contains a set of default options:

-a /.amd_mnt -l syslog /host /etc/amd.map /net /etc/amd.map

The -a option sets the default mount location which is specified here as /.amd_mnt. The -l option specifies the default log file; however, when syslogd is used all log activity will be sent to the system log daemon. The /host directory is used to mount an exported file system from a remote host, while /net directory is used to mount an exported file system from an IP address. The /etc/amd.map file defines the default options for AMD exports.

The Anon FTP option permits anonymous FTP connections. Select this option to make this machine an anonymous FTP server. Be aware of the security risks involved with this option. Another menu will be displayed to explain the security risks and configuration in depth.

The Gateway configuration menu will set the machine up to be a gateway as explained previously. This can be used to unset the Gateway option if you accidentally selected it during the installation process.

The Inetd option can be used to configure or completely disable the inetd(8) daemon as discussed above.

The Mail option is used to configure the system's default MTA or Mail Transfer Agent. Selecting this option will bring up the following menu:

Figure 2-52. Select a default MTA

Here you are offered a choice as to which MTA to install and set as the default. An MTA is nothing more than a mail server which delivers email to users on the system or the Internet.

Selecting Sendmail will install the popular sendmail server which is the FreeBSD default. The Sendmail local option will set sendmail to be the default MTA, but disable its ability to receive incoming email from the Internet. The other options here, Postfix and Exim act similar to Sendmail. They both deliver email; however, some users prefer these alternatives to the sendmail MTA.

After selecting an MTA, or choosing not to select an MTA, the network configuration menu will appear with the next option being NFS client.

The NFS client option will configure the system to communicate with a server via NFS. An NFS server makes file systems available to other machines on the network via the NFS protocol. If this is a stand alone machine, this option can remain unselected. The system may require more configuration later; see Section 19.6 for more information about client and server configuration.

Below that option is the NFS server option, permitting you to set the system up as an NFS server. This adds the required information to start up the RPC remote procedure call services. RPC is used to coordinate connections between hosts and programs.

Next in line is the Ntpdate option, which deals with time synchronization. When selected, a menu like the one below shows up:

Figure 2-53. Ntpdate Configuration

From this menu, select the server which is the closest to your location. Selecting a close one will make the time synchronization more accurate as a server further from your location may have more connection latency.

The next option is the PCNFSD selection. This option will install the net/pcnfsd package from the ports collection. This is a useful utility which provides NFS authentication services for systems which are unable to provide their own, such as Microsoft's MS-DOS operating system.

Now you must scroll down a bit to see the other options:

Figure 2-54. Network Configuration Lower-level

The rpcbind(8), rpc.statd(8), and rpc.lockd(8) utilities are all used for Remote Procedure Calls (RPC). The rpcbind utility manages communication between NFS servers and clients, and is required for NFS servers to operate correctly. The rpc.statd daemon interacts with the rpc.statd daemon on other hosts to provide status monitoring. The reported status is usually held in the /var/db/statd.status file. The next option listed here is the rpc.lockd option, which, when selected, will provide file locking services. This is usually used with rpc.statd to monitor what hosts are requesting locks and how frequently they request them. While these last two options are marvelous for debugging, they are not required for NFS servers and clients to operate correctly.

As you progress down the list the next item here is Routed, which is the routing daemon. The routed(8) utility manages network routing tables, discovers multicast routers, and supplies a copy of the routing tables to any physically connected host on the network upon request. This is mainly used for machines which act as a gateway for the local network (see the icmp(4) and udp(4) manual pages). When selected, a menu will be presented requesting the default location of the utility. The default location is already defined for you and can be selected with the Enter key. You will then be presented with yet another menu, this time asking for the flags you wish to pass on to routed. The default is -q and it should already appear on the screen.

Next in line is the Rwhod option which, when selected, will start the rwhod(8) daemon during system initialization. The rwhod utility broadcasts system messages across the network periodically, or collects them when in ``consumer'' mode. More information can be found in the ruptime(1) and rwho(1) manual pages.

The next to the last option in the list is for the sshd(8) daemon. This is the secure shell server for OpenSSH and it is highly recommended over the standard telnet and FTP servers. The sshd server is used to create a secure connection from one host to another by using encrypted connections.

Finally there is the TCP Extensions option. This enables the TCP Extensions defined in RFC 1323 and RFC 1644. While on many hosts this can speed up connections, it can also cause some connections to be dropped. It is not recommended for servers, but may be beneficial for stand alone machines.

Now that you have configured the network services, you can scroll up to the very top item which is Exit and continue on to the next configuration section.


2.9.12 Configure X Server

In order to use a graphical user interface such as KDE, GNOME, or others, the X server will need to be configured.

Note: In order to run XFree86 as a non root user you will need to have x11/wrapper installed. This is installed by default beginning with FreeBSD 4.7. For earlier versions this can be added from the Package Selection menu.

To see whether your video card is supported, check the XFree86 web site.

                      User Confirmation Requested 
        Would you like to configure your X server at this time?

                            [ Yes ]   No

Warning: It is necessary to know your monitor specifications and video card information. Equipment damage can occur if settings are incorrect. If you do not have this information, select [ No ] and perform the configuration after installation when you have the information using /stand/sysinstall, selecting Configure and then XFree86. Improper configuration of the X server at this time can leave the machine in a frozen state. It is often advised to configure the X server once the installation has completed.

If you have graphics card and monitor information, select [ Yes ] and press Enter to proceed with configuring the X server.

Figure 2-55. Select Configuration Method Menu

There are several ways to configure the X server. Use the arrow keys to select one of the methods and press Enter. Be sure to read all instructions carefully.

The xf86cfg and xf86cfg -textmode methods may make the screen go dark and take a few seconds to start. Be patient.

The following will illustrate the use of the xf86config configuration tool. The configuration choices you make will depend on the hardware in the system so your choices will probably be different than those shown:

                                Message
 You have configured and been running the mouse daemon. 
 Choose "/dev/sysmouse" as the mouse port and "SysMouse" or
 "MouseSystems" as the mouse protocol in the X configuration utility. 

                                 [ OK ]

                      [ Press enter to continue ]

This indicates that the mouse daemon previously configured has been detected. Press Enter to continue.

Starting xf86config will display a brief introduction:

This program will create a basic XF86Config file, based on menu selections you
make.

The XF86Config file usually resides in /usr/X11R6/etc/X11 or /etc/X11. A sample
XF86Config file is supplied with XFree86; it is configured for a standard
VGA card and monitor with 640x480 resolution. This program will ask for a
pathname when it is ready to write the file.

You can either take the sample XF86Config as a base and edit it for your
configuration, or let this program produce a base XF86Config file for your
configuration and fine-tune it.

Before continuing with this program, make sure you know what video card
you have, and preferably also the chipset it uses and the amount of video
memory on your video card. SuperProbe may be able to help with this.

Press enter to continue, or ctrl-c to abort.

Pressing Enter will start the mouse configuration. Be sure to follow the instructions and use ``Mouse Systems'' as the mouse protocol and /dev/sysmouse as the mouse port even if using a PS/2 mouse is shown as an illustration.

First specify a mouse protocol type. Choose one from the following list:

 1.  Microsoft compatible (2-button protocol)
 2.  Mouse Systems (3-button protocol) & FreeBSD moused protocol
 3.  Bus Mouse
 4.  PS/2 Mouse
 5.  Logitech Mouse (serial, old type, Logitech protocol)
 6.  Logitech MouseMan (Microsoft compatible)
 7.  MM Series
 8.  MM HitTablet
 9.  Microsoft IntelliMouse

If you have a two-button mouse, it is most likely of type 1, and if you have
a three-button mouse, it can probably support both protocol 1 and 2. There are
two main varieties of the latter type: mice with a switch to select the
protocol, and mice that default to 1 and require a button to be held at
boot-time to select protocol 2. Some mice can be convinced to do 2 by sending
a special sequence to the serial port (see the ClearDTR/ClearRTS options).

Enter a protocol number: 2

You have selected a Mouse Systems protocol mouse. If your mouse is normally
in Microsoft-compatible mode, enabling the ClearDTR and ClearRTS options
may cause it to switch to Mouse Systems mode when the server starts.

Please answer the following question with either 'y' or 'n'.
Do you want to enable ClearDTR and ClearRTS? n

You have selected a three-button mouse protocol. It is recommended that you
do not enable Emulate3Buttons, unless the third button doesn't work.

Please answer the following question with either 'y' or 'n'.
Do you want to enable Emulate3Buttons? y

Now give the full device name that the mouse is connected to, for example
/dev/tty00. Just pressing enter will use the default, /dev/mouse.
On FreeBSD, the default is /dev/sysmouse.

Mouse device: /dev/sysmouse

The keyboard is the next item to be configured. A generic 101-key model is shown for illustration. Any name may be used for the variant or simply press Enter to accept the default value.

Please select one of the following keyboard types that is the better
description of your keyboard. If nothing really matches,
choose 1 (Generic 101-key PC)

  1  Generic 101-key PC                                
  2  Generic 102-key (Intl) PC                         
  3  Generic 104-key PC                                
  4  Generic 105-key (Intl) PC                         
  5  Dell 101-key PC                                   
  6  Everex STEPnote                                   
  7  Keytronic FlexPro                                 
  8  Microsoft Natural                                 
  9  Northgate OmniKey 101                             
 10  Winbook Model XP5                                 
 11  Japanese 106-key                                  
 12  PC-98xx Series                                    
 13  Brazilian ABNT2                                   
 14  HP Internet                                       
 15  Logitech iTouch                                   
 16  Logitech Cordless Desktop Pro                     
 17  Logitech Internet Keyboard                        
 18  Logitech Internet Navigator Keyboard              
 19  Compaq Internet                                   
 20  Microsoft Natural Pro                             
 21  Genius Comfy KB-16M                               
 22  IBM Rapid Access                                  
 23  IBM Rapid Access II                               
 24  Chicony Internet Keyboard                         
 25  Dell Internet Keyboard                            

Enter a number to choose the keyboard.

1


Please select the layout corresponding to your keyboard


  1  U.S. English                                      
  2  U.S. English w/ ISO9995-3                         
  3  U.S. English w/ deadkeys                          
  4  Albanian                                          
  5  Arabic                                            
  6  Armenian                                          
  7  Azerbaidjani                                      
  8  Belarusian                                        
  9  Belgian                                           
 10  Bengali                                           
 11  Brazilian                                         
 12  Bulgarian                                         
 13  Burmese                                           
 14  Canadian                                          
 15  Croatian                                          
 16  Czech                                             
 17  Czech (qwerty)                                    
 18  Danish                                            

Enter a number to choose the country.
Press enter for the next page

1


Please enter a variant name for 'us' layout. Or just press enter
for default variant

us


Please answer the following question with either 'y' or 'n'.
Do you want to select additional XKB options (group switcher,
group indicator, etc.)? n

Next, we proceed to the configuration for the monitor. Do not exceed the ratings of your monitor. Damage could occur. If you have any doubts, do the configuration after you have the information.

Now we want to set the specifications of the monitor. The two critical
parameters are the vertical refresh rate, which is the rate at which the
whole screen is refreshed, and most importantly the horizontal sync rate,
which is the rate at which scanlines are displayed.

The valid range for horizontal sync and vertical sync should be documented
in the manual of your monitor. If in doubt, check the monitor database
/usr/X11R6/lib/X11/doc/Monitors to see if your monitor is there.

Press enter to continue, or ctrl-c to abort.



You must indicate the horizontal sync range of your monitor. You can either
select one of the predefined ranges below that correspond to industry-
standard monitor types, or give a specific range.

It is VERY IMPORTANT that you do not specify a monitor type with a horizontal
sync range that is beyond the capabilities of your monitor. If in doubt,
choose a conservative setting.

    hsync in kHz; monitor type with characteristic modes
 1  31.5; Standard VGA, 640x480 @ 60 Hz
 2  31.5 - 35.1; Super VGA, 800x600 @ 56 Hz
 3  31.5, 35.5; 8514 Compatible, 1024x768 @ 87 Hz interlaced (no 800x600)
 4  31.5, 35.15, 35.5; Super VGA, 1024x768 @ 87 Hz interlaced, 800x600 @ 56 Hz
 5  31.5 - 37.9; Extended Super VGA, 800x600 @ 60 Hz, 640x480 @ 72 Hz
 6  31.5 - 48.5; Non-Interlaced SVGA, 1024x768 @ 60 Hz, 800x600 @ 72 Hz
 7  31.5 - 57.0; High Frequency SVGA, 1024x768 @ 70 Hz
 8  31.5 - 64.3; Monitor that can do 1280x1024 @ 60 Hz
 9  31.5 - 79.0; Monitor that can do 1280x1024 @ 74 Hz
10  31.5 - 82.0; Monitor that can do 1280x1024 @ 76 Hz
11  Enter your own horizontal sync range

Enter your choice (1-11): 6

You must indicate the vertical sync range of your monitor. You can either
select one of the predefined ranges below that correspond to industry-
standard monitor types, or give a specific range. For interlaced modes,
the number that counts is the high one (e.g. 87 Hz rather than 43 Hz).

 1  50-70
 2  50-90
 3  50-100
 4  40-150
 5  Enter your own vertical sync range

Enter your choice: 2

You must now enter a few identification/description strings, namely an
identifier, a vendor name, and a model name. Just pressing enter will fill
in default names.

The strings are free-form, spaces are allowed.
Enter an identifier for your monitor definition: Hitachi

The selection of a video card driver from a list is next. If you pass your card on the list, continue to press Enter and the list will repeat. Only an excerpt from the list is shown:

Now we must configure video card specific settings. At this point you can
choose to make a selection out of a database of video card definitions.
Because there can be variation in Ramdacs and clock generators even
between cards of the same model, it is not sensible to blindly copy
the settings (e.g. a Device section). For this reason, after you make a
selection, you will still be asked about the components of the card, with
the settings from the chosen database entry presented as a strong hint.

The database entries include information about the chipset, what driver to
run, the Ramdac and ClockChip, and comments that will be included in the
Device section. However, a lot of definitions only hint about what driver
to run (based on the chipset the card uses) and are untested.

If you can't find your card in the database, there's nothing to worry about.
You should only choose a database entry that is exactly the same model as
your card; choosing one that looks similar is just a bad idea (e.g. a
GemStone Snail 64 may be as different from a GemStone Snail 64+ in terms of
hardware as can be).

Do you want to look at the card database? y



288  Matrox Millennium G200 8MB                        mgag200
289  Matrox Millennium G200 SD 16MB                    mgag200
290  Matrox Millennium G200 SD 4MB                     mgag200
291  Matrox Millennium G200 SD 8MB                     mgag200
292  Matrox Millennium G400                            mgag400
293  Matrox Millennium II 16MB                         mga2164w
294  Matrox Millennium II 4MB                          mga2164w
295  Matrox Millennium II 8MB                          mga2164w
296  Matrox Mystique                                   mga1064sg
297  Matrox Mystique G200 16MB                         mgag200
298  Matrox Mystique G200 4MB                          mgag200
299  Matrox Mystique G200 8MB                          mgag200
300  Matrox Productiva G100 4MB                        mgag100
301  Matrox Productiva G100 8MB                        mgag100
302  MediaGX                                           mediagx
303  MediaVision Proaxcel 128                          ET6000
304  Mirage Z-128                                      ET6000
305  Miro CRYSTAL VRX                                  Verite 1000

Enter a number to choose the corresponding card definition.
Press enter for the next page, q to continue configuration.

288

Your selected card definition:

Identifier: Matrox Millennium G200 8MB
Chipset:    mgag200
Driver:     mga
Do NOT probe clocks or use any Clocks line.

Press enter to continue, or ctrl-c to abort.



Now you must give information about your video card. This will be used for
the "Device" section of your video card in XF86Config.

You must indicate how much video memory you have. It is probably a good
idea to use the same approximate amount as that detected by the server you
intend to use. If you encounter problems that are due to the used server
not supporting the amount memory you have (e.g. ATI Mach64 is limited to
1024K with the SVGA server), specify the maximum amount supported by the
server.

How much video memory do you have on your video card:

 1  256K
 2  512K
 3  1024K
 4  2048K
 5  4096K
 6  Other

Enter your choice: 6

Amount of video memory in Kbytes: 8192

You must now enter a few identification/description strings, namely an
identifier, a vendor name, and a model name. Just pressing enter will fill
in default names (possibly from a card definition).

Your card definition is Matrox Millennium G200 8MB.

The strings are free-form, spaces are allowed.
Enter an identifier for your video card definition:

Next, the video modes are set for the resolutions desired. Typically, useful ranges are 640x480, 800x600, and 1024x768 but those are a function of video card capability, monitor size, and eye comfort. When selecting a color depth, select the highest mode that your card will support.

For each depth, a list of modes (resolutions) is defined. The default
resolution that the server will start-up with will be the first listed
mode that can be supported by the monitor and card.
Currently it is set to:

"640x480" "800x600" "1024x768" "1280x1024" for 8-bit
"640x480" "800x600" "1024x768" "1280x1024" for 16-bit
"640x480" "800x600" "1024x768" "1280x1024" for 24-bit

Modes that cannot be supported due to monitor or clock constraints will
be automatically skipped by the server.

 1  Change the modes for 8-bit (256 colors)
 2  Change the modes for 16-bit (32K/64K colors)
 3  Change the modes for 24-bit (24-bit color)
 4  The modes are OK, continue.

Enter your choice: 2

Select modes from the following list:

 1  "640x400"
 2  "640x480"
 3  "800x600"
 4  "1024x768"
 5  "1280x1024"
 6  "320x200"
 7  "320x240"
 8  "400x300"
 9  "1152x864"
 a  "1600x1200"
 b  "1800x1400"
 c  "512x384"

Please type the digits corresponding to the modes that you want to select.
For example, 432 selects "1024x768" "800x600" "640x480", with a
default mode of 1024x768.

Which modes? 432

You can have a virtual screen (desktop), which is screen area that is larger
than the physical screen and which is panned by moving the mouse to the edge
of the screen. If you don't want virtual desktop at a certain resolution,
you cannot have modes listed that are larger. Each color depth can have a
differently-sized virtual screen

Please answer the following question with either 'y' or 'n'.
Do you want a virtual screen that is larger than the physical screen? n



For each depth, a list of modes (resolutions) is defined. The default
resolution that the server will start-up with will be the first listed
mode that can be supported by the monitor and card.
Currently it is set to:

"640x480" "800x600" "1024x768" "1280x1024" for 8-bit
"1024x768" "800x600" "640x480" for 16-bit
"640x480" "800x600" "1024x768" "1280x1024" for 24-bit

Modes that cannot be supported due to monitor or clock constraints will
be automatically skipped by the server.

 1  Change the modes for 8-bit (256 colors)
 2  Change the modes for 16-bit (32K/64K colors)
 3  Change the modes for 24-bit (24-bit color)
 4  The modes are OK, continue.

Enter your choice: 4



Please specify which color depth you want to use by default:

  1  1 bit (monochrome)                                
  2  4 bits (16 colors)                                
  3  8 bits (256 colors)                               
  4  16 bits (65536 colors)                            
  5  24 bits (16 million colors)                       

Enter a number to choose the default depth.

4

Finally, the configuration needs to be saved. Be sure to enter /etc/XF86Config as the location for saving the configuration.

I am going to write the XF86Config file now. Make sure you don't accidently
overwrite a previously configured one.

Shall I write it to /etc/X11/XF86Config? y

If the configuration fails, you can try the configuration again by selecting [ Yes ] when the following message appears:

          User Confirmation Requested
The XFree86 configuration process seems to have
failed.  Would you like to try again?

             [ Yes ]         No

If you have trouble configuring XFree86, select [ No ] and press Enter and continue with the installation process. After installation you can use xf86cfg -textmode or xf86config to access the command line configuration utilities as root. There is an additional method for configuring XFree86 described in Chapter 5. If you choose not to configure XFree86 at this time the next menu will be for package selection.

The default setting which allows the server to be killed is the hotkey sequence Ctrl+Alt+Backspace. This can be executed if something is wrong with the server settings and prevent hardware damage.

The default setting that allows video mode switching will permit changing of the mode while running X with the hotkey sequence Ctrl+Alt++ or Ctrl+Alt+-.

After installation, the display can be adjusted for height, width, or centering by using xvidtune after you have XFree86 running with xvidtune.

There are warnings that improper settings can damage your equipment. Heed them. If in doubt, do not do it. Instead, use the monitor controls to adjust the display for X Window. There may be some display differences when switching back to text mode, but it is better than damaging equipment.

Read the xvidtune(1) manual page before making any adjustments.

Following a successful XFree86 configuration, it will proceed to the selection of a default desktop.


2.9.13 Select Default X Desktop

There are a variety of window managers available. They range from very basic environments to full desktop environments with a large suite of software. Some require only minimal disk space and low memory while others with more features require much more. The best way to determine which is most suitable for you is to try a few different ones. Those are available from the ports collection or as packages and can be added after installation.

You can select one of the popular desktops to be installed and configured as the default desktop. This will allow you to start it right after installation.

Figure 2-56. Select Default Desktop

Use the arrow keys to select a desktop and press Enter. Installation of the selected desktop will proceed.


2.9.14 Install Packages

Packages are pre-compiled binaries and are a convenient way to install software.

Installation of one package is shown for purposes of illustration. Additional packages can also be added at this time if desired. After installation /stand/sysinstall can be used to add additional packages.

                     User Confirmation Requested
 The FreeBSD package collection is a collection of hundreds of
 ready-to-run applications, from text editors to games to WEB servers
 and more. Would you like to browse the collection now? 

                            [ Yes ]   No

Selecting [ Yes ] and pressing Enter will be followed by the Package Selection screens:

Figure 2-57. Select Package Category

Only packages on the current installation media are available for installation at any given time.

All packages available will be displayed if All is selected or you can select a particular category. Highlight your selection with the arrow keys and press Enter.

A menu will display showing all the packages available for the selection made:

Figure 2-58. Select Packages

The bash shell is shown selected. Select as many as desired by highlighting the package and pressing the Space key. A short description of each package will appear in the lower left corner of the screen.

Pressing the Tab key will toggle between the last selected package, [ OK ], and [ Cancel ].

When you have finished marking the packages for installation, press Tab once to toggle to the [ OK ] and press Enter to return to the Package Selection menu.

The left and right arrow keys will also toggle between [ OK ] and [ Cancel ]. This method can also be used to select [ OK ] and press Enter to return to the Package Selection menu.

Figure 2-59. Install Packages

Use the Tab and arrow keys to select [ Install ] and press Enter. You will then need to confirm that you want to install the packages:

Figure 2-60. Confirm Package Installation

Selecting [ OK ] and pressing Enter will start the package installation. Installing messages will appear until completed. Make note if there are any error messages.

The final configuration continues after packages are installed. If you end up not selecting any packages, and wish to return to the final configuration, select Install anyways.


2.9.15 Add Users/Groups

You should add at least one user during the installation so that you can use the system without being logged in as root. The root partition is generally small and running applications as root can quickly fill it. A bigger danger is noted below:

                     User Confirmation Requested
 Would you like to add any initial user accounts to the system? Adding
 at least one account for yourself at this stage is suggested since
 working as the "root" user is dangerous (it is easy to do things which
 adversely affect the entire system). 

                            [ Yes ]   No

Select [ Yes ] and press Enter to continue with adding a user.

Figure 2-61. Select User

Select User with the arrow keys and press Enter.

Figure 2-62. Add User Information

The following descriptions will appear in the lower part of the screen as the items are selected with Tab to assist with entering the required information:

Login ID

The login name of the new user (mandatory).

UID

The numerical ID for this user (leave blank for automatic choice).

Group

The login group name for this user (leave blank for automatic choice).

Password

The password for this user (enter this field with care!).

Full name

The user's full name (comment).

Member groups

The groups this user belongs to (i.e. gets access rights for).

Home directory

The user's home directory (leave blank for default).

Login shell

The user's login shell (leave blank for default, e.g. /bin/sh).

The login shell was changed from /bin/sh to /usr/local/bin/bash to use the bash shell that was previously installed as a package. Do not try to use a shell that does not exist or you will not be able to login. The most common shell used in the BSD-world is the C shell, which can be indicated as /bin/tcsh.

The user was also added to the wheel group to be able to become a superuser with root privileges.

When you are satisfied, press [ OK ] and the User and Group Management menu will redisplay:

Figure 2-63. Exit User and Group Management

Groups can also be added at this time if specific needs are known. Otherwise, this may be accessed through using /stand/sysinstall after installation is completed.

When you are finished adding users, select Exit with the arrow keys and press Enter to continue the installation.


2.9.16 Set the root Password

                        Message
 Now you must set the system manager's password.  
 This is the password you'll use to log in as "root". 

                         [ OK ] 

               [ Press enter to continue ]

Press Enter to set the root password.

The password will need to be typed in twice correctly. Needless to say, make sure you have a way of finding the password if you forget.

Changing local password for root. 
New password : 
Retype new password :

The installation will continue after the password is successfully entered.


2.9.17 Exiting Install

If you need to configure additional network devices or any other configuration, you can do it at this point or after installation with /stand/sysinstall.

                     User Confirmation Requested
 Visit the general configuration menu for a chance to set any last
 options? 

                              Yes   [ No ]

Select [ No ] with the arrow keys and press Enter to return to the Main Installation Menu.

Figure 2-64. Exit Install

Select [X Exit Install] with the arrow keys and press Enter. You will be asked to confirm exiting the installation:

                     User Confirmation Requested
 Are you sure you wish to exit? The system will reboot (be sure to  
 remove any floppies from the drives). 

                            [ Yes ]   No

Select [ Yes ] and remove the floppy if booting from the floppy. The CDROM drive is locked until the machine starts to reboot. The CDROM drive is then unlocked and the disk can be removed from drive (quickly).

The system will reboot so watch for any error messages that may appear.


2.9.18 FreeBSD Bootup

2.9.18.1 FreeBSD Bootup on the i386

If everything went well, you will see messages scroll off the screen and you will arrive at a login prompt. You can view the content of the messages by pressing Scroll-Lock and using PgUp and PgDn. Pressing Scroll-Lock again will return to the prompt.

The entire message may not display (buffer limitation) but it can be viewed from the command line after logging in by typing dmesg at the prompt.

Login using the username/password you set during installation (rpratt, in this example). Avoid logging in as root except when necessary.

Typical boot messages (version information omitted):

Copyright (c) 1992-2002 The FreeBSD Project. 
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved. 

Timecounter "i8254"  frequency 1193182 Hz
CPU: AMD-K6(tm) 3D processor (300.68-MHz 586-class CPU)
  Origin = "AuthenticAMD"  Id = 0x580  Stepping = 0
  Features=0x8001bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,MMX> 
  AMD Features=0x80000800<SYSCALL,3DNow!> 
real memory  = 268435456 (262144K bytes) 
config> di sn0 
config> di lnc0 
config> di le0 
config> di ie0 
config> di fe0 
config> di cs0 
config> di bt0  
config> di aic0 
config> di aha0 
config> di adv0 
config> q 
avail memory = 256311296 (250304K bytes)
Preloaded elf kernel "kernel" at 0xc0491000. 
Preloaded userconfig_script "/boot/kernel.conf" at 0xc049109c. 
md0: Malloc disk 
Using $PIR table, 4 entries at 0xc00fde60
npx0: <math processor> on motherboard 
npx0: INT 16 interface 
pcib0: <Host to PCI bridge> on motherboard 
pci0: <PCI bus> on pcib0 
pcib1: <VIA 82C598MVP (Apollo MVP3) PCI-PCI (AGP) bridge> at device 1.0 on pci0 
pci1: <PCI bus> on pcib1 
pci1: <Matrox MGA G200 AGP graphics accelerator> at 0.0 irq 11 
isab0: <VIA 82C586 PCI-ISA bridge> at device 7.0 on pci0 
isa0: <ISA bus> on isab0 
atapci0: <VIA 82C586 ATA33 controller> port 0xe000-0xe00f at device 7.1 on pci0 
ata0: at 0x1f0 irq 14 on atapci0 
ata1: at 0x170 irq 15 on atapci0 
uhci0: <VIA 83C572 USB controller> port 0xe400-0xe41f irq 10 at device 7.2 on pci0 
usb0: <VIA 83C572 USB controller> on uhci0 
usb0: USB revision 1.0 
uhub0: VIA UHCI root hub, class 9/0, rev 1.00/1.00, addr 1 
uhub0: 2 ports with 2 removable, self powered 
chip1: <VIA 82C586B ACPI interface> at device 7.3 on pci0 
ed0: <NE2000 PCI Ethernet (RealTek 8029)> port 0xe800-0xe81f irq 9 at
device 10.0 on pci0 
ed0: address 52:54:05:de:73:1b, type NE2000 (16 bit) 
isa0: too many dependant configs (8) 
isa0: unexpected small tag 14 
fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
fdc0: FIFO enabled, 8 bytes threshold 
fd0: <1440-KB 3.5" drive> on fdc0 drive 0 
atkbdc0: <keyboard controller (i8042)> at port 0x60-0x64 on isa0 
atkbd0: <AT Keyboard> flags 0x1 irq 1 on atkbdc0 
kbd0 at atkbd0 
psm0: <PS/2 Mouse> irq 12 on atkbdc0 
psm0: model Generic PS/2 mouse, device ID 0 
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
sc0: <System console> at flags 0x1 on isa0 
sc0: VGA <16 virtual consoles, flags=0x300> 
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0 
sio0: type 16550A 
sio1 at port 0x2f8-0x2ff irq 3 on isa0 
sio1: type 16550A 
ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0 
ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode 
ppc0: FIFO with 16/16/15 bytes threshold 
ppbus0: IEEE1284 device found /NIBBLE
Probing for PnP devices on ppbus0: 
plip0: <PLIP network interface> on ppbus0 
lpt0: <Printer> on ppbus0 
lpt0: Interrupt-driven port 
ppi0: <Parallel I/O> on ppbus0
ad0: 8063MB <IBM-DHEA-38451> [16383/16/63] at ata0-master using UDMA33 
ad2: 8063MB <IBM-DHEA-38451> [16383/16/63] at ata1-master using UDMA33 
acd0: CDROM <DELTA OTC-H101/ST3 F/W by OIPD> at ata0-slave using PIO4 
Mounting root from ufs:/dev/ad0s1a 
swapon: adding /dev/ad0s1b as swap device 
Automatic boot in progress... 
/dev/ad0s1a: FILESYSTEM CLEAN; SKIPPING CHECKS 
/dev/ad0s1a: clean, 48752 free (552 frags, 6025 blocks, 0.9% fragmentation)
/dev/ad0s1f: FILESYSTEM CLEAN; SKIPPING CHECKS 
/dev/ad0s1f: clean, 128997 free (21 frags, 16122 blocks, 0.0% fragmentation)
/dev/ad0s1g: FILESYSTEM CLEAN; SKIPPING CHECKS
/dev/ad0s1g: clean, 3036299 free (43175 frags, 374073 blocks, 1.3% fragmentation)
/dev/ad0s1e: filesystem CLEAN; SKIPPING CHECKS 
/dev/ad0s1e: clean, 128193 free (17 frags, 16022 blocks, 0.0% fragmentation)
Doing initial network setup: hostname. 
ed0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255
        inet6 fe80::5054::5ff::fede:731b%ed0 prefixlen 64 tentative scopeid 0x1
        ether 52:54:05:de:73:1b
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384 
        inet6 fe80::1%lo0 prefixlen 64 scopeid 0x8 
        inet6 ::1 prefixlen 128 
        inet 127.0.0.1 netmask 0xff000000 
Additional routing options: IP gateway=YES TCP keepalive=YES
routing daemons:. 
additional daemons: syslogd. 
Doing additional network setup:. 
Starting final network daemons: creating ssh RSA host key 
Generating public/private rsa1 key pair.
Your identification has been saved in /etc/ssh/ssh_host_key. 
Your public key has been saved in /etc/ssh/ssh_host_key.pub. 
The key fingerprint is: 
cd:76:89:16:69:0e:d0:6e:f8:66:d0:07:26:3c:7e:2d root@k6-2.example.com
 creating ssh DSA host key 
Generating public/private dsa key pair.
Your identification has been saved in /etc/ssh/ssh_host_dsa_key. 
Your public key has been saved in /etc/ssh/ssh_host_dsa_key.pub. 
The key fingerprint is: 
f9:a1:a9:47:c4:ad:f9:8d:52:b8:b8:ff:8c:ad:2d:e6 root@k6-2.example.com.
setting ELF ldconfig path: /usr/lib /usr/lib/compat /usr/X11R6/lib
/usr/local/lib 
a.out ldconfig path: /usr/lib/aout /usr/lib/compat/aout /usr/X11R6/lib/aout 
starting standard daemons: inetd cron sshd usbd sendmail.
Initial rc.i386 initialization:. 
rc.i386 configuring syscons: blank_time screensaver moused. 
Additional ABI support: linux. 
Local package initialization:. 
Additional TCP options:. 

FreeBSD/i386 (k6-2.example.com) (ttyv0)

login: rpratt 
Password:

Generating the RSA and DSA keys may take some time on slower machines. This happens only on the initial boot-up of a new installation. Subsequent boots will be faster.

If the X server has been configured and a Default Desktop chosen, it can be started by typing startx at the command line.


2.9.18.2 Bootup of FreeBSD on the Alpha

Once the install procedure has finished, you will be able to start FreeBSD by typing something like this to the SRM prompt:

>>>BOOT DKC0

This instructs the firmware to boot the specified disk. To make FreeBSD boot automatically in the future, use these commands:

>>> SET BOOT_OSFLAGS A
>>> SET BOOT_FILE ''
>>> SET BOOTDEF_DEV DKC0
>>> SET AUTO_ACTION BOOT

The boot messages will be similar (but not identical) to those produced by FreeBSD booting on the i386.


2.9.19 FreeBSD Shutdown

It is important to properly shutdown the operating system. Do not just turn off power. First, become a superuser by typing su at the command line and entering the root password. This will work only if the user is a member of the wheel group. Otherwise, login as root and use shutdown -h now.

The operating system has halted. 
Please press any key to reboot.

It is safe to turn off the power after the shutdown command has been issued and the message ``Please press any key to reboot'' appears. If any key is pressed instead of turning off the power switch, the system will reboot.

You could also use the Ctrl+Alt+Del key combination to reboot the system, however this is not recommended during normal operation.


2.10 Supported Hardware

FreeBSD currently runs on a wide variety of ISA, VLB, EISA, and PCI bus-based PCs with Intel, AMD, Cyrix, or NexGen ``x86'' processors, as well as a number of machines based on the Compaq Alpha processor. Support for generic IDE or ESDI drive configurations, various SCSI controllers, PCMCIA cards, USB devices, and network and serial cards is also provided. FreeBSD also supports IBM's microchannel (MCA) bus.

A list of supported hardware is provided with each FreeBSD release in the FreeBSD Hardware Notes. This document can usually be found in a file named HARDWARE.TXT, in the top-level directory of a CDROM or FTP distribution or in sysinstall's documentation menu. It lists, for a given architecture, what hardware devices are known to be supported by each release of FreeBSD. Copies of the supported hardware list for various releases and architectures can also be found on the Release Information page of the FreeBSD Web site.


2.11 Troubleshooting

The following section covers basic installation troubleshooting, such as common problems people have reported. There are also a few questions and answers for people wishing to dual-boot FreeBSD with MS-DOS.


2.11.1 What to Do If Something Goes Wrong

Due to various limitations of the PC architecture, it is impossible for probing to be 100% reliable, however, there are a few things you can do if it fails.

Check the Hardware Notes document for your version of FreeBSD to make sure your hardware is supported.

If your hardware is supported and you still experience lock-ups or other problems, reset your computer, and when the visual kernel configuration option is given, choose it. This will allow you to go through your hardware and supply information to the system about it. The kernel on the boot disks is configured assuming that most hardware devices are in their factory default configuration in terms of IRQs, IO addresses, and DMA channels. If your hardware has been reconfigured, you will most likely need to use the configuration editor to tell FreeBSD where to find things.

It is also possible that a probe for a device not present will cause a later probe for another device that is present to fail. In that case, the probes for the conflicting driver(s) should be disabled.

Note: Some installation problems can be avoided or alleviated by updating the firmware on various hardware components, most notably the motherboard. The motherboard firmware may also be referred to as BIOS and most of the motherboard or computer manufactures have a website where the upgrades and upgrade information may be located.

Most manufacturers strongly advise against upgrading the motherboard BIOS unless there is a good reason for doing so, which could possibly be a critical update of sorts. The upgrade process can go wrong, causing permanent damage to the BIOS chip.

Warning: Do not disable any drivers you will need during the installation, such as your screen (sc0). If the installation wedges or fails mysteriously after leaving the configuration editor, you have probably removed or changed something you should not have. Reboot and try again.

In configuration mode, you can:

  • List the device drivers installed in the kernel.

  • Disable device drivers for hardware that is not present in your system.

  • Change IRQs, DRQs, and IO port addresses used by a device driver.

After adjusting the kernel to match your hardware configuration, type Q to boot with the new settings. Once the installation has completed, any changes you made in the configuration mode will be permanent so you do not have to reconfigure every time you boot. It is still highly likely that you will eventually want to build a custom kernel.


2.11.2 Dealing with Existing MS-DOS® Partitions

Many users wish to install FreeBSD on PCs inhabited by Microsoft based operating systems. For those instances, FreeBSD has a utility known as FIPS. This utility can be found in the tools directory on the install CD-ROM, or downloaded from one of various FreeBSD mirrors.

The FIPS utility allows you to split an existing MS-DOS partition into two pieces, preserving the original partition and allowing you to install onto the second free piece. You first need to defragment your MS-DOS partition using the Windows; Disk Defragmenter utility (go into Explorer, right-click on the hard drive, and choose to defrag your hard drive), or use Norton Disk Tools. Now you can run the FIPS utility. It will prompt you for the rest of the information, just follow the on screen instructions. Afterwards, you can reboot and install FreeBSD on the new free slice. See the Distributions menu for an estimate of how much free space you will need for the kind of installation you want.

There is also a very useful product from PowerQuest (http://www.powerquest.com) called PartitionMagic. This application has far more functionality than FIPS, and is highly recommended if you plan to add/remove operating systems often. It does cost money, so if you plan to install FreeBSD and keep it installed, FIPS will probably be fine for you.


2.11.3 Using MS-DOS and Windows® File Systems

At this time, FreeBSD does not support file systems compressed with the Double Space™ application. Therefore the file system will need to be uncompressed before FreeBSD can access the data. This can be done by running the Compression Agent located in the Start> Programs > System Tools menu.

FreeBSD can support MS-DOS based file systems. This requires you use the mount_msdos(8) command (in FreeBSD 5.X, the command is mount_msdosfs(8)) with the required parameters. The utilities most common usage is:

# mount_msdos /dev/ad0s1 /mnt

In this example, the MS-DOS file system is located on the first partition of the primary hard disk. Your situation may be different, check the output from the dmesg, and mount commands. They should produce enough information too give an idea of the partition layout.

Note: Extended MS-DOS file systems are usually mapped after the FreeBSD partitions. In other words, the slice number may be higher than the ones FreeBSD is using. For instance, the first MS-DOS partition may be /dev/ad0s1, the FreeBSD partition may be /dev/ad0s2, with the extended MS-DOS partition being located on /dev/ad0s3. To some, this can be confusing at first.

NTFS partitions can also be mounted in a similar manner using the mount_ntfs(8) command.


2.11.4 Alpha User's Questions and Answers

This section answers some commonly asked questions about installing FreeBSD on Alpha systems.

2.11.4.1. Can I boot from the ARC or Alpha BIOS Console?
2.11.4.2. Help, I have no space! Do I need to delete everything first?
2.11.4.3. Can I mount my Compaq Tru64 or VMS filesystems?

2.11.4.1. Can I boot from the ARC or Alpha BIOS Console?

No. FreeBSD, like Compaq Tru64 and VMS, will only boot from the SRM console.

2.11.4.2. Help, I have no space! Do I need to delete everything first?

Unfortunately, yes.

2.11.4.3. Can I mount my Compaq Tru64 or VMS filesystems?

No, not at this time.


2.12 Advanced Installation Guide

Contributed by Valentino Vaschetto.

This section describes how to install FreeBSD in exceptional cases.


2.12.1 Installing FreeBSD on a System without a Monitor or Keyboard

This type of installation is called a ``headless install'', because the machine that you are trying to install FreeBSD on either does not have a monitor attached to it, or does not even have a VGA output. How is this possible you ask? Using a serial console. A serial console is basically using another machine to act as the main display and keyboard for a system. To do this, just follow the steps to create installation floppies, explained in Section 2.2.7.

To modify these floppies to boot into a serial console, follow these steps:

  1. Enabling the Boot Floppies to Boot into a Serial Console

    If you were to boot into the floppies that you just made, FreeBSD would boot into its normal install mode. We want FreeBSD to boot into a serial console for our install. To do this, you have to mount the kern.flp floppy onto your FreeBSD system using the mount(8) command.

    # mount /dev/fd0 /floppy
    

    Now that you have the floppy mounted, you must change into the floppy directory:

    # cd /floppy
    

    Here is where you must set the floppy to boot into a serial console. You have to make a file called boot.config containing /boot/loader -h. All this does is pass a flag to the bootloader to boot into a serial console.

    # echo "/boot/loader -h" > boot.config
    

    Now that you have your floppy configured correctly, you must unmount the floppy using the umount(8) command:

    # cd /
    # umount /mnt
    

    Now you can remove the floppy from the floppy drive.

  2. Connecting Your Null Modem Cable

    You now need to connect a null modem cable between the two machines. Just connect the cable to the serial ports of the 2 machines. A normal serial cable will not work here, you need a null modem cable because it has some of the wires inside crossed over.

  3. Booting Up for the Install

    It is now time to go ahead and start the install. Put the kern.flp floppy in the floppy drive of the machine you are doing the headless install on, and power on the machine.

  4. Connecting to Your Headless Machine

    Now you have to connect to that machine with cu(1):

    # cu -l /dev/cuaa0
    

That's it! You should now be able to control the headless machine through your cu session. It will ask you to put in the mfsroot.flp, and then it will come up with a selection of what kind of terminal to use. Select the FreeBSD color console and proceed with your install!


2.13 Preparing Your Own Installation Media

Note: To prevent repetition, ``FreeBSD disk'' in this context means a FreeBSD CDROM or DVD that you have purchased or produced yourself.

There may be some situations in which you need to create your own FreeBSD installation media and/or source. This might be physical media, such as a tape, or a source that sysinstall can use to retrieve the files, such as a local FTP site, or an MS-DOS partition.

For example:

  • You have many machines connected to your local network, and one FreeBSD disk. You want to create a local FTP site using the contents of the FreeBSD disk, and then have your machines use this local FTP site instead of needing to connect to the Internet.

  • You have a FreeBSD disk, and FreeBSD does not recognize your CD/DVD drive, but MS-DOS/Windows does. You want to copy the FreeBSD installations files to a DOS partition on the same computer, and then install FreeBSD using those files.

  • The computer you want to install on does not have a CD/DVD drive or a network card, but you can connect a ``Laplink-style'' serial or parallel cable to a computer that does.

  • You want to create a tape that can be used to install FreeBSD.


2.13.1 Creating an Installation CDROM

As part of each release, the FreeBSD project makes available two CDROM images (``ISO images''). These images can be written (``burned'') to CDs if you have a CD writer, and then used to install FreeBSD. If you have a CD writer, and bandwidth is cheap, then this is the easiest way to install FreeBSD.

  1. Download the Correct ISO Images

    The ISO images for each release can be downloaded from ftp://ftp.FreeBSD.org/pub/FreeBSD/ISO-IMAGES-arch/version or the closest mirror. Substitute arch and version as appropriate.

    That directory will normally contain the following images:

    Table 2-5. FreeBSD ISO Image Names and Meanings

    Filename Contains
    version-mini.iso Everything you need to install FreeBSD.
    version-disc1.iso Everything you need to install FreeBSD, and as many additional third party packages as would fit on the disc.
    version-disc2.iso A ``live filesystem'', which is used in conjunction with the ``Repair'' facility in sysinstall. A copy of the FreeBSD CVS tree. As many additional third party packages as would fit on the disc.

    You must download one of either the mini ISO image, or the image of disc one. Do not download both of them, since the disc one image contains everything that the mini ISO image contains.

    Use the mini ISO if Internet access is cheap for you. It will let you install FreeBSD, and you can then install third party packages by downloading them using the ports/packages system (see Chapter 4) as necessary.

    Use the image of disc one if you want a reasonable selection of third party packages on the disc as well.

    The additional disc images are useful, but not essential, especially if you have high-speed access to the Internet.

  2. Write the CDs

    You must then write the CD images to disc. If you will be doing this on another FreeBSD system then see Section 12.5 for more information (in particular, Section 12.5.3 and Section 12.5.4).

    If you will be doing this on another platform then you will need to use whatever utilities exist to control your CD writer on that platform. The images provided are in the standard ISO format, which many CD writing applications support.


2.13.2 Creating a Local FTP Site with a FreeBSD Disk

FreeBSD disks are laid out in the same way as the FTP site. This makes it very easy for you to create a local FTP site that can be used by other machines on your network when installing FreeBSD.

  1. On the FreeBSD computer that will host the FTP site, ensure that the CDROM is in the drive, and mounted on /cdrom.

    # mount /cdrom
    
  2. Create an account for anonymous FTP in /etc/passwd. Do this by editing /etc/passwd using vipw(8) and adding this line.

    ftp:*:99:99::0:0:FTP:/cdrom:/nonexistent
    
  3. Ensure that the FTP service is enabled in /etc/inetd.conf.

Anyone with network connectivity to your machine can now chose a media type of FTP and type in ftp://your machine after picking ``Other'' in the FTP sites menu during the install.

Warning: This approach is OK for a machine that is on your local network, and that is protected by your firewall. Offering up FTP services to other machines over the Internet (and not your local network) exposes your computer to the attention of crackers and other undesirables. We strongly recommend that you follow good security practices if you do this.


2.13.3 Creating Installation Floppies

If you must install from floppy disk (which we suggest you do not do), either due to unsupported hardware or simply because you insist on doing things the hard way, you must first prepare some floppies for the installation.

At a minimum, you will need as many 1.44 MB or 1.2 MB floppies as it takes to hold all the files in the bin (binary distribution) directory. If you are preparing the floppies from DOS, then they MUST be formatted using the MS-DOS FORMAT command. If you are using Windows, use Explorer to format the disks (right-click on the A: drive, and select ``Format''.

Do not trust factory pre-formatted floppies. Format them again yourself, just to be sure. Many problems reported by our users in the past have resulted from the use of improperly formatted media, which is why we are making a point of it now.

If you are creating the floppies on another FreeBSD machine, a format is still not a bad idea, though you do not need to put a DOS filesystem on each floppy. You can use the disklabel and newfs commands to put a UFS filesystem on them instead, as the following sequence of commands (for a 3.5" 1.44 MB floppy) illustrates:

# fdformat -f 1440 fd0.1440
# disklabel -w -r fd0.1440 floppy3
# newfs -t 2 -u 18 -l 1 -i 65536 /dev/fd0

Note: Use fd0.1200 and floppy5 for 5.25" 1.2 MB disks.

Then you can mount and write to them like any other filesystem.

After you have formatted the floppies, you will need to copy the files to them. The distribution files are split into chunks conveniently sized so that five of them will fit on a conventional 1.44 MB floppy. Go through all your floppies, packing as many files as will fit on each one, until you have all of the distributions you want packed up in this fashion. Each distribution should go into a subdirectory on the floppy, e.g.: a:\bin\bin.aa, a:\bin\bin.ab, and so on.

Once you come to the Media screen during the install process, select ``Floppy'' and you will be prompted for the rest.


2.13.4 Installing from an MS-DOS Partition

To prepare for an installation from an MS-DOS partition, copy the files from the distribution into a directory called freebsd in the root directory of the partition. For example, c:\freebsd. The directory structure of the CDROM or FTP site must be partially reproduced within this directory, so we suggest using the DOS xcopy command if you are copying it from a CD. For example, to prepare for a minimal installation of FreeBSD:

C:\> md c:\freebsd
C:\> xcopy e:\bin c:\freebsd\bin\ /s
C:\> xcopy e:\manpages c:\freebsd\manpages\ /s

Assuming that C: is where you have free space and E: is where your CDROM is mounted.

If you do not have a CDROM drive, you can download the distribution from ftp.FreeBSD.org. Each distribution is in its own directory; for example, the base distribution can be found in the 5.2.1/base/ directory.

Note: In the 4.X and older releases of FreeBSD the ``base'' distribution is called ``bin''. Adjust the sample commands and URLs above accordingly, if you are using one of these versions.

For as many distributions you wish to install from an MS-DOS partition (and you have the free space for), install each one under c:\freebsd -- the BIN distribution is the only one required for a minimum installation.


2.13.5 Creating an Installation Tape

Installing from tape is probably the easiest method, short of an online FTP install or CDROM install. The installation program expects the files to be simply tarred onto the tape. After getting all of the distribution files you are interested in, simply tar them onto the tape:

# cd /freebsd/distdir
# tar cvf /dev/rwt0 dist1 ... dist2

When you perform the installation, you should make sure that you leave enough room in some temporary directory (which you will be allowed to choose) to accommodate the full contents of the tape you have created. Due to the non-random access nature of tapes, this method of installation requires quite a bit of temporary storage. You should expect to require as much temporary storage as you have data written on tape.

Note: When starting the installation, the tape must be in the drive before booting from the boot floppy. The installation probe may otherwise fail to find it.


2.13.6 Before Installing over a Network

There are three types of network installations available. Serial port (SLIP or PPP), Parallel port (PLIP (laplink cable)), or Ethernet (a standard Ethernet controller (includes some PCMCIA)).

The SLIP support is rather primitive, and limited primarily to hard-wired links, such as a serial cable running between a laptop computer and another computer. The link should be hard-wired as the SLIP installation does not currently offer a dialing capability; that facility is provided with the PPP utility, which should be used in preference to SLIP whenever possible.

If you are using a modem, then PPP is almost certainly your only choice. Make sure that you have your service provider's information handy as you will need to know it fairly early in the installation process.

If you use PAP or CHAP to connect your ISP (in other words, if you can connect to the ISP in Windows without using a script), then all you will need to do is type in dial at the ppp prompt. Otherwise, you will need to know how to dial your ISP using the ``AT commands'' specific to your modem, as the PPP dialer provides only a very simple terminal emulator. Please refer to the user-ppp handbook and FAQ entries for further information. If you have problems, logging can be directed to the screen using the command set log local ....

If a hard-wired connection to another FreeBSD (2.0-R or later) machine is available, you might also consider installing over a ``laplink'' parallel port cable. The data rate over the parallel port is much higher than what is typically possible over a serial line (up to 50 kbytes/sec), thus resulting in a quicker installation.

Finally, for the fastest possible network installation, an Ethernet adapter is always a good choice! FreeBSD supports most common PC Ethernet cards; a table of supported cards (and their required settings) is provided in the Hardware Notes for each release of FreeBSD. If you are using one of the supported PCMCIA Ethernet cards, also be sure that it is plugged in before the laptop is powered on! FreeBSD does not, unfortunately, currently support hot insertion of PCMCIA cards during installation.

You will also need to know your IP address on the network, the netmask value for your address class, and the name of your machine. If you are installing over a PPP connection and do not have a static IP, fear not, the IP address can be dynamically assigned by your ISP. Your system administrator can tell you which values to use for your particular network setup. If you will be referring to other hosts by name rather than IP address, you will also need a name server and possibly the address of a gateway (if you are using PPP, it is your provider's IP address) to use in talking to it. If you want to install by FTP via a HTTP proxy, you will also need the proxy's address. If you do not know the answers to all or most of these questions, then you should really probably talk to your system administrator or ISP before trying this type of installation.


2.13.6.1 Before Installing via NFS

The NFS installation is fairly straight-forward. Simply copy the FreeBSD distribution files you want onto an NFS server and then point the NFS media selection at it.

If this server supports only ``privileged port'' (as is generally the default for Sun workstations), you will need to set this option in the Options menu before installation can proceed.

If you have a poor quality Ethernet card which suffers from very slow transfer rates, you may also wish to toggle the appropriate Options flag.

In order for NFS installation to work, the server must support subdir mounts, for example, if your FreeBSD 5.2.1 distribution directory lives on: ziggy:/usr/archive/stuff/FreeBSD, then ziggy will have to allow the direct mounting of /usr/archive/stuff/FreeBSD, not just /usr or /usr/archive/stuff.

In FreeBSD's /etc/exports file, this is controlled by the -alldirs options. Other NFS servers may have different conventions. If you are getting ``permission denied'' messages from the server, then it is likely that you do not have this enabled properly.


Chapter 3 UNIX Basics

Rewritten by Chris Shumway.

3.1 Synopsis

The following chapter will cover the basic commands and functionality of the FreeBSD operating system. Much of this material is relevant for any UNIX like operating system. Feel free to skim over this chapter if you are familiar with the material. If you are new to FreeBSD, then you will definitely want to read through this chapter carefully.

After reading this chapter, you will know:

  • How to use the ``virtual consoles'' of FreeBSD.

  • How UNIX file permissions work.

  • The default FreeBSD file system layout.

  • The FreeBSD disk organization.

  • How to mount and unmount file systems.

  • What processes, daemons, and signals are.

  • What a shell is, and how to change your default login environment.

  • How to use basic text editors.

  • What devices and device nodes are.

  • What binary format is used under FreeBSD.

  • How to read manual pages for more information.


3.2 Virtual Consoles and Terminals

FreeBSD can be used in various ways. One of them is typing commands to a text terminal. A lot of the flexibility and power of a UNIX operating system is readily available at your hands when using FreeBSD this way. This section describes what ``terminals'' and ``consoles'' are, and how you can use them in FreeBSD.


3.2.1 The Console

If you have not configured FreeBSD to automatically start a graphical environment during startup, the system will present you with a login prompt after it boots, right after the startup scripts finish running. You will see something similar to:

Additional ABI support:.
Local package initialization:.
Additional TCP options:.

Fri Sep 20 13:01:06 EEST 2002

FreeBSD/i386 (pc3.example.org) (ttyv0)

login:

The messages might be a bit different on your system, but you will see something similar. The last two lines are what we are interested in right now. The second last line reads:

FreeBSD/i386 (pc3.example.org) (ttyv0)

This line contains some bits of information about the system you have just booted. You are looking at a ``FreeBSD'' console, running on an Intel or compatible processor of the x86 architecture[1]. The name of this machine (every UNIX machine has a name) is pc3.example.org, and you are now looking at its system console--the ttyv0 terminal.

Finally, the last line is always:

login:

This is the part where you are supposed to type in your ``username'' to log into FreeBSD. The next section describes how you can do this.


3.2.2 Logging into FreeBSD

FreeBSD is a multiuser, multiprocessing system. This is the formal description that is usually given to a system that can be used by many different people, who simultaneously run a lot of programs on a single machine.

Every multiuser system needs some way to distinguish one ``user'' from the rest. In FreeBSD (and all the UNIX like operating systems), this is accomplished by requiring that every user must ``log into'' the system before being able to run programs. Every user has a unique name (the ``username'') and a personal, secret key (the ``password''). FreeBSD will ask for these two before allowing a user to run any programs.

Right after FreeBSD boots and finishes running its startup scripts[2], it will present you with a prompt and ask for a valid username:

login:

For the sake of this example, let us assume that your username is john. Type john at this prompt and press Enter. You should then be presented with a prompt to enter a ``password'':

login: john
Password:

Type in john's password now, and press Enter. The password is not echoed! You need not worry about this right now. Suffice it to say that it is done for security reasons.

If you have typed your password correctly, you should by now be logged into FreeBSD and ready to try out all the available commands.

You should see the MOTD or message of the day followed by a command prompt (a #, $, or % character). This indicates you have successfully logged into FreeBSD.


3.2.3 Multiple Consoles

Running UNIX commands in one console is fine, but FreeBSD can run many programs at once. Having one console where commands can be typed would be a bit of a waste when an operating system like FreeBSD can run dozens of programs at the same time. This is where ``virtual consoles'' can be very helpful.

FreeBSD can be configured to present you with many different virtual consoles. You can switch from one of them to any other virtual console by pressing a couple of keys on your keyboard. Each console has its own different output channel, and FreeBSD takes care of properly redirecting keyboard input and monitor output as you switch from one virtual console to the next.

Special key combinations have been reserved by FreeBSD for switching consoles[3]. You can use Alt-F1, Alt-F2, through Alt-F8 to switch to a different virtual console in FreeBSD.

As you are switching from one console to the next, FreeBSD takes care of saving and restoring the screen output. The result is an ``illusion'' of having multiple ``virtual'' screens and keyboards that you can use to type commands for FreeBSD to run. The programs that you launch on one virtual console do not stop running when that console is not visible. They continue running when you have switched to a different virtual console.


3.2.4 The /etc/ttys File

The default configuration of FreeBSD will start up with eight virtual consoles. This is not a hardwired setting though, and you can easily customize your installation to boot with more or fewer virtual consoles. The number and settings of the virtual consoles are configured in the /etc/ttys file.

You can use the /etc/ttys file to configure the virtual consoles of FreeBSD. Each uncommented line in this file (lines that do not start with a # character) contains settings for a single terminal or virtual console. The default version of this file that ships with FreeBSD configures nine virtual consoles, and enables eight of them. They are the lines that start with ttyv:

# name  getty                           type    status          comments
#
ttyv0   "/usr/libexec/getty Pc"         cons25  on  secure
# Virtual terminals
ttyv1   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv2   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv3   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv4   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv5   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv6   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv7   "/usr/libexec/getty Pc"         cons25  on  secure
ttyv8   "/usr/X11R6/bin/xdm -nodaemon"  xterm   off secure

For a detailed description of every column in this file and all the options you can use to set things up for the virtual consoles, consult the ttys(5) manual page.


3.2.5 Single User Mode Console

A detailed description of what ``single user mode'' is can be found in Section 7.6.2. It is worth noting that there is only one console when you are running FreeBSD in single user mode. There are no virtual consoles available. The settings of the single user mode console can also be found in the /etc/ttys file. Look for the line that starts with console:

# name  getty                           type    status          comments
#
# If console is marked "insecure", then init will ask for the root password
# when going to single-user mode.
console none                            unknown off secure

Note: As the comments above the console line indicate, you can edit this line and change secure to insecure. If you do that, when FreeBSD boots into single user mode, it will still ask for the root password.

Be careful when changing this to insecure. If you ever forget the root password, booting into single user mode is a bit involved. It is still possible, but it might be a bit hard for someone who is not very comfortable with the FreeBSD booting process and the programs involved.


3.3 Permissions

FreeBSD, being a direct descendant of BSD UNIX, is based on several key UNIX concepts. The first and most pronounced is that FreeBSD is a multi-user operating system. The system can handle several users all working simultaneously on completely unrelated tasks. The system is responsible for properly sharing and managing requests for hardware devices, peripherals, memory, and CPU time fairly to each user.

Because the system is capable of supporting multiple users, everything the system manages has a set of permissions governing who can read, write, and execute the resource. These permissions are stored as three octets broken into three pieces, one for the owner of the file, one for the group that the file belongs to, and one for everyone else. This numerical representation works like this:

Value Permission Directory Listing
0 No read, no write, no execute ---
1 No read, no write, execute --x
2 No read, write, no execute -w-
3 No read, write, execute -wx
4 Read, no write, no execute r--
5 Read, no write, execute r-x
6 Read, write, no execute rw-
7 Read, write, execute rwx

You can use the -l command line argument to ls(1) to view a long directory listing that includes a column with information about a file's permissions for the owner, group, and everyone else. For example, a ls -l in an arbitrary directory may show:

% ls -l
total 530
-rw-r--r--  1 root  wheel     512 Sep  5 12:31 myfile
-rw-r--r--  1 root  wheel     512 Sep  5 12:31 otherfile
-rw-r--r--  1 root  wheel    7680 Sep  5 12:31 email.txt
...

Here is how the first column of ls -l is broken up:

-rw-r--r--

The first (leftmost) character tells if this file is a regular file, a directory, a special character device, a socket, or any other special pseudo-file device. In this case, the - indicates a regular file. The next three characters, rw- in this example, give the permissions for the owner of the file. The next three characters, r--, give the permissions for the group that the file belongs to. The final three characters, r--, give the permissions for the rest of the world. A dash means that the permission is turned off. In the case of this file, the permissions are set so the owner can read and write to the file, the group can read the file, and the rest of the world can only read the file. According to the table above, the permissions for this file would be 644, where each digit represents the three parts of the file's permission.

This is all well and good, but how does the system control permissions on devices? FreeBSD actually treats most hardware devices as a file that programs can open, read, and write data to just like any other file. These special device files are stored on the /dev directory.

Directories are also treated as files. They have read, write, and execute permissions. The executable bit for a directory has a slightly different meaning than that of files. When a directory is marked executable, it means it can be traversed into, that is, it is possible to ``cd'' (change directory) into it. This also means that within the directory it is possible to access files whose names are known (subject, of course, to the permissions on the files themselves).

In particular, in order to perform a directory listing, read permission must be set on the directory, whilst to delete a file that one knows the name of, it is necessary to have write and execute permissions to the directory containing the file.

There are more permission bits, but they are primarily used in special circumstances such as setuid binaries and sticky directories. If you want more information on file permissions and how to set them, be sure to look at the chmod(1) manual page.


3.3.1 Symbolic Permissions

Contributed by Tom Rhodes.

Symbolic permissions, sometimes referred to as symbolic expressions, use characters in place of octal values to assign permissions to files or directories. Symbolic expressions use the syntax of (who) (action) (permissions), where the following values are available:

Option Letter Represents
(who) u User
(who) g Group owner
(who) o Other
(who) a All (``world'')
(action) + Adding permissions
(action) - Removing permissions
(action) = Explicitly set permissions
(permissions) r Read
(permissions) w Write
(permissions) x Execute
(permissions) t Sticky bit
(permissions) s Set UID or GID

These values are used with the chmod(1) command just like before, but with letters. For an example, you could use the following command to block other users from accessing FILE:

% chmod go= FILE

A comma separated list can be provided when more than one set of changes to a file must be made. For example the following command will remove the groups and ``world'' write permission on FILE, then it adds the execute permissions for everyone:

% chmod go-w,a+x FILE

3.4 Directory Structure

The FreeBSD directory hierarchy is fundamental to obtaining an overall understanding of the system. The most important concept to grasp is that of the root directory, ``/''. This directory is the first one mounted at boot time and it contains the base system necessary to prepare the operating system for multi-user operation. The root directory also contains mount points for every other file system that you may want to mount.

A mount point is a directory where additional file systems can be grafted onto the root file system. Standard mount points include /usr, /var, /mnt, and /cdrom. These directories are usually referenced to entries in the file /etc/fstab. /etc/fstab is a table of various file systems and mount points for reference by the system. Most of the file systems in /etc/fstab are mounted automatically at boot time from the script rc(8) unless they contain the noauto option. Consult the fstab(5) manual page for more information on the format of the /etc/fstab file and the options it contains.

A complete description of the file system hierarchy is available in hier(7). For now, a brief overview of the most common directories will suffice.

Directory Description
/ Root directory of the file system.
/bin/ User utilities fundamental to both single-user and multi-user environments.
/boot/ Programs and configuration files used during operating system bootstrap.
/boot/defaults/ Default bootstrapping configuration files; see loader.conf(5).
/dev/ Device nodes; see intro(4).
/etc/ System configuration files and scripts.
/etc/defaults/ Default system configuration files; see rc(8).
/etc/mail/ Configuration files for mail transport agents such as sendmail(8).
/etc/namedb/ named configuration files; see named(8).
/etc/periodic/ Scripts that are run daily, weekly, and monthly, via cron(8); see periodic(8).
/etc/ppp/ ppp configuration files; see ppp(8).
/mnt/ Empty directory commonly used by system administrators as a temporary mount point.
/proc/ Process file system; see procfs(5), mount_procfs(8).
/root/ Home directory for the root account.
/sbin/ System programs and administration utilities fundamental to both single-user and multi-user environments.
/stand/ Programs used in a standalone environment.
/tmp/ Temporary files, usually a mfs(8) memory-based file system (the contents of /tmp are usually NOT preserved across a system reboot).
/usr/ The majority of user utilities and applications.
/usr/bin/ Common utilities, programming tools, and applications.
/usr/include/ Standard C include files.
/usr/lib/ Archive libraries.
/usr/libdata/ Miscellaneous utility data files.
/usr/libexec/ System daemons & system utilities (executed by other programs).
/usr/local/ Local executables, libraries, etc. Also used as the default destination for the FreeBSD ports framework. Within /usr/local, the general layout sketched out by hier(7) for /usr should be used. Exceptions are the man directory, which is directly under /usr/local rather than under /usr/local/share, and the ports documentation is in share/doc/port.
/usr/obj/ Architecture-specific target tree produced by building the /usr/src tree.
/usr/ports The FreeBSD ports collection (optional).
/usr/sbin/ System daemons & system utilities (executed by users).
/usr/share/ Architecture-independent files.
/usr/src/ BSD and/or local source files.
/usr/X11R6/ X11R6 distribution executables, libraries, etc (optional).
/var/ Multi-purpose log, temporary, transient, and spool files.
/var/log/ Miscellaneous system log files.
/var/mail/ User mailbox files.
/var/spool/ Miscellaneous printer and mail system spooling directories.
/var/tmp/ Temporary files that are kept between system reboots.
/var/yp NIS maps.



3.5 Disk Organization

The smallest unit of organization that FreeBSD uses to find files is the filename. Filenames are case-sensitive, which means that readme.txt and README.TXT are two separate files. FreeBSD does not use the extension (.txt) of a file to determine whether the file is program, or a document, or some other form of data.

Files are stored in directories. A directory may contain no files, or it may contain many hundreds of files. A directory can also contain other directories, allowing you to build up a hierarchy of directories within one another. This makes it much easier to organize your data.

Files and directories are referenced by giving the file or directory name, followed by a forward slash, /, followed by any other directory names that are necessary. If you have directory foo, which contains directory bar, which contains the file readme.txt, then the full name, or path to the file is foo/bar/readme.txt.

Directories and files are stored in a filesystem. Each filesystem contains exactly one directory at the very top level, called the root directory for that filesystem. This root directory can then contain other directories.

So far this is probably similar to any other operating system you may have used. There are a few differences; for example, MS-DOS uses \ to separate file and directory names, while Mac OS® uses :.

FreeBSD does not use drive letters, or other drive names in the path. You would not write c:/foo/bar/readme.txt on FreeBSD.

Instead, one filesystem is designated the root filesystem. The root filesystem's root directory is referred to as /. Every other filesystem is then mounted under the root filesystem. No matter how many disks you have on your FreeBSD system, every directory appears to be part of the same disk.

Suppose you have three filesystems, called A, B, and C. Each filesystem has one root directory, which contains two other directories, called A1, A2 (and likewise B1, B2 and C1, C2).

Call A the root filesystem. If you used the ls command to view the contents of this directory you would see two subdirectories, A1 and A2. The directory tree looks like this:

A filesystem must be mounted on to a directory in another filesystem. So now suppose that you mount filesystem B on to the directory A1. The root directory of B replaces A1, and the directories in B appear accordingly:

Any files that are in the B1 or B2 directories can be reached with the path /A1/B1 or /A1/B2 as necessary. Any files that were in /A1 have been temporarily hidden. They will reappear if B is unmounted from A.

If B had been mounted on A2 then the diagram would look like this:

and the paths would be /A2/B1 and /A2/B2 respectively.

Filesystems can be mounted on top of one another. Continuing the last example, the C filesystem could be mounted on top of the B1 directory in the B filesystem, leading to this arrangement:

Or C could be mounted directly on to the A filesystem, under the A1 directory:

If you are familiar with MS-DOS, this is similar, although not identical, to the join command.

This is not normally something you need to concern yourself with. Typically you create filesystems when installing FreeBSD and decide where to mount them, and then never change them unless you add a new disk.

It is entirely possible to have one large root filesystem, and not need to create any others. There are some drawbacks to this approach, and one advantage.

Benefits of Multiple Filesystems

  • Different filesystems can have different mount options. For example, with careful planning, the root filesystem can be mounted read-only, making it impossible for you to inadvertently delete or edit a critical file. Separating user-writable filesystems, such as /home, from other filesystems also allows them to be mounted nosuid; this option prevents the suid/guid bits on executables stored on the filesystem from taking effect, possibly improving security.

  • FreeBSD automatically optimizes the layout of files on a filesystem, depending on how the filesystem is being used. So a filesystem that contains many small files that are written frequently will have a different optimization to one that contains fewer, larger files. By having one big filesystem this optimization breaks down.

  • FreeBSD's filesystems are very robust should you lose power. However, a power loss at a critical point could still damage the structure of the filesystem. By splitting your data over multiple filesystems it is more likely that the system will still come up, making it easier for you to restore from backup as necessary.

Benefit of a Single Filesystem

  • Filesystems are a fixed size. If you create a filesystem when you install FreeBSD and give it a specific size, you may later discover that you need to make the partition bigger. This is not easily accomplished without backing up, recreating the filesystem with the new size, and then restoring the backed up data.

    Important: FreeBSD 4.4 and later versions feature the growfs(8) command, which makes it possible to increase the size of filesystem on the fly, removing this limitation.

Filesystems are contained in partitions. This does not have the same meaning as the common usage of the term partition (for example, MS-DOS partition), because of FreeBSD's UNIX heritage. Each partition is identified by a letter from a through to h. Each partition can contain only one filesystem, which means that filesystems are often described by either their typical mount point in the filesystem hierarchy, or the letter of the partition they are contained in.

FreeBSD also uses disk space for swap space. Swap space provides FreeBSD with virtual memory. This allows your computer to behave as though it has much more memory than it actually does. When FreeBSD runs out of memory it moves some of the data that is not currently being used to the swap space, and moves it back in (moving something else out) when it needs it.

Some partitions have certain conventions associated with them.

Partition Convention
a Normally contains the root filesystem
b Normally contains swap space
c Normally the same size as the enclosing slice. This allows utilities that need to work on the entire slice (for example, a bad block scanner) to work on the c partition. You would not normally create a filesystem on this partition.
d Partition d used to have a special meaning associated with it, although that is now gone. To this day, some tools may operate oddly if told to work on partition d, so sysinstall will not normally create partition d.

Each partition-that-contains-a-filesystem is stored in what FreeBSD calls a slice. Slice is FreeBSD's term for what the common call partitions, and again, this is because of FreeBSD's UNIX background. Slices are numbered, starting at 1, through to 4.

Slice numbers follow the device name, prefixed with an s, starting at 1. So ``da0s1'' is the first slice on the first SCSI drive. There can only be four physical slices on a disk, but you can have logical slices inside physical slices of the appropriate type. These extended slices are numbered starting at 5, so ``ad0s5'' is the first extended slice on the first IDE disk. These devices are used by file systems that expect to occupy a slice.

Slices, ``dangerously dedicated'' physical drives, and other drives contain partitions, which are represented as letters from a to h. This letter is appended to the device name, so ``da0a'' is the a partition on the first da drive, which is ``dangerously dedicated''. ``ad1s3e'' is the fifth partition in the third slice of the second IDE disk drive.

Finally, each disk on the system is identified. A disk name starts with a code that indicates the type of disk, and then a number, indicating which disk it is. Unlike slices, disk numbering starts at 0. Common codes that you will see are listed in Table 3-1.

When referring to a partition FreeBSD requires that you also name the slice and disk that contains the partition, and when referring to a slice you should also refer to the disk name. Do this by listing the disk name, s, the slice number, and then the partition letter. Examples are shown in Example 3-1.

Example 3-2 shows a conceptual model of the disk layout that should help make things clearer.

In order to install FreeBSD you must first configure the disk slices, then create partitions within the slice you will use for FreeBSD, and then create a filesystem (or swap space) in each partition, and decide where that filesystem will be mounted.

Table 3-1. Disk Device Codes

Code Meaning
ad ATAPI (IDE) disk
da SCSI direct access disk
acd ATAPI (IDE) CDROM
cd SCSI CDROM
fd Floppy disk

Example 3-1. Sample Disk, Slice, and Partition Names

Name Meaning
ad0s1a The first partition (a) on the first slice (s1) on the first IDE disk (ad0).
da1s2e The fifth partition (e) on the second slice (s2) on the second SCSI disk (da1).

Example 3-2. Conceptual Model of a Disk

This diagram shows FreeBSD's view of the first IDE disk attached to the system. Assume that the disk is 4 GB in size, and contains two 2 GB slices (MS-DOS partitions). The first slice contains a MS-DOS disk, C:, and the second slice contains a FreeBSD installation. This example FreeBSD installation has three partitions, and a swap partition.

The three partitions will each hold a filesystem. Partition a will be used for the root filesystem, e for the /var directory hierarchy, and f for the /usr directory hierarchy.


3.6 Mounting and Unmounting File Systems

The file system is best visualized as a tree, rooted, as it were, at /. /dev, /usr, and the other directories in the root directory are branches, which may have their own branches, such as /usr/local, and so on.

There are various reasons to house some of these directories on separate file systems. /var contains the directories log/, spool/, and various types of temporary files, and as such, may get filled up. Filling up the root file system is not a good idea, so splitting /var from / is often favorable.

Another common reason to contain certain directory trees on other file systems is if they are to be housed on separate physical disks, or are separate virtual disks, such as Network File System mounts, or CDROM drives.


3.6.1 The fstab File

During the boot process, file systems listed in /etc/fstab are automatically mounted (unless they are listed with the noauto option).

The /etc/fstab file contains a list of lines of the following format:

device       /mount-point fstype     options      dumpfreq     passno
device

A device name (which should exist), as explained in Section 12.2.

mount-point

A directory (which should exist), on which to mount the file system.

fstype

The file system type to pass to mount(8). The default FreeBSD file system is ufs.

options

Either rw for read-write file systems, or ro for read-only file systems, followed by any other options that may be needed. A common option is noauto for file systems not normally mounted during the boot sequence. Other options are listed in the mount(8) manual page.

dumpfreq

This is used by dump(8) to determine which file systems require dumping. If the field is missing, a value of zero is assumed.

passno

This determines the order in which file systems should be checked. File systems that should be skipped should have their passno set to zero. The root file system (which needs to be checked before everything else) should have its passno set to one, and other file systems' passno should be set to values greater than one. If more than one file systems have the same passno then fsck(8) will attempt to check file systems in parallel if possible.


3.6.2 The mount Command

The mount(8) command is what is ultimately used to mount file systems.

In its most basic form, you use:

# mount device mountpoint

There are plenty of options, as mentioned in the mount(8) manual page, but the most common are:

Mount Options

-a

Mount all the file systems listed in /etc/fstab. Except those marked as ``noauto'', excluded by the -t flag, or those that are already mounted.

-d

Do everything except for the actual mount system call. This option is useful in conjunction with the -v flag to determine what mount(8) is actually trying to do.

-f

Force the mount of an unclean file system (dangerous), or forces the revocation of write access when downgrading a file system's mount status from read-write to read-only.

-r

Mount the file system read-only. This is identical to using the rdonly argument to the -o option.

-t fstype

Mount the given file system as the given file system type, or mount only file systems of the given type, if given the -a option.

``ufs'' is the default file system type.

-u

Update mount options on the file system.

-v

Be verbose.

-w

Mount the file system read-write.

The -o option takes a comma-separated list of the options, including the following:

nodev

Do not interpret special devices on the file system. This is a useful security option.

noexec

Do not allow execution of binaries on this file system. This is also a useful security option.

nosuid

Do not interpret setuid or setgid flags on the file system. This is also a useful security option.


3.6.3 The umount Command

The umount(8) command takes, as a parameter, one of a mountpoint, a device name, or the -a or -A option.

All forms take -f to force unmounting, and -v for verbosity. Be warned that -f is not generally a good idea. Forcibly unmounting file systems might crash the computer or damage data on the file system.

-a and -A are used to unmount all mounted file systems, possibly modified by the file system types listed after -t. -A, however, does not attempt to unmount the root file system.


3.7 Processes

FreeBSD is a multi-tasking operating system. This means that it seems as though more than one program is running at once. Each program running at any one time is called a process. Every command you run will start at least one new process, and there are a number of system processes that run all the time, keeping the system functional.

Each process is uniquely identified by a number called a process ID, or PID, and, like files, each process also has one owner and group. The owner and group information is used to determine what files and devices the process can open, using the file permissions discussed earlier. Most processes also have a parent process. The parent process is the process that started them. For example, if you are typing commands to the shell then the shell is a process, and any commands you run are also processes. Each process you run in this way will have your shell as its parent process. The exception to this is a special process called init(8). init is always the first process, so its PID is always 1. init is started automatically by the kernel when FreeBSD starts.

Two commands are particularly useful to see the processes on the system, ps(1) and top(1). The ps command is used to show a static list of the currently running processes, and can show their PID, how much memory they are using, the command line they were started with, and so on. The top command displays all the running processes, and updates the display every few seconds, so that you can interactively see what your computer is doing.

By default, ps only shows you the commands that are running and are owned by you. For example:

% ps
  PID  TT  STAT      TIME COMMAND
  298  p0  Ss     0:01.10 tcsh
 7078  p0  S      2:40.88 xemacs mdoc.xsl (xemacs-21.1.14)
37393  p0  I      0:03.11 xemacs freebsd.dsl (xemacs-21.1.14)
48630  p0  S      2:50.89 /usr/local/lib/netscape-linux/navigator-linux-4.77.bi
48730  p0  IW     0:00.00 (dns helper) (navigator-linux-)
72210  p0  R+     0:00.00 ps
  390  p1  Is     0:01.14 tcsh
 7059  p2  Is+    1:36.18 /usr/local/bin/mutt -y
 6688  p3  IWs    0:00.00 tcsh
10735  p4  IWs    0:00.00 tcsh
20256  p5  IWs    0:00.00 tcsh
  262  v0  IWs    0:00.00 -tcsh (tcsh)
  270  v0  IW+    0:00.00 /bin/sh /usr/X11R6/bin/startx -- -bpp 16
  280  v0  IW+    0:00.00 xinit /home/nik/.xinitrc -- -bpp 16
  284  v0  IW     0:00.00 /bin/sh /home/nik/.xinitrc
  285  v0  S      0:38.45 /usr/X11R6/bin/sawfish

As you can see in this example, the output from ps(1) is organized into a number of columns. PID is the process ID discussed earlier. PIDs are assigned starting from 1, go up to 99999, and wrap around back to the beginning when you run out. The TT column shows the tty the program is running on, and can safely be ignored for the moment. STAT shows the program's state, and again, can be safely ignored. TIME is the amount of time the program has been running on the CPU--this is usually not the elapsed time since you started the program, as most programs spend a lot of time waiting for things to happen before they need to spend time on the CPU. Finally, COMMAND is the command line that was used to run the program.

ps(1) supports a number of different options to change the information that is displayed. One of the most useful sets is auxww. a displays information about all the running processes, not just your own. u displays the username of the process' owner, as well as memory usage. x displays information about daemon processes, and ww causes ps(1) to display the full command line, rather than truncating it once it gets too long to fit on the screen.

The output from top(1) is similar. A sample session looks like this:

% top
last pid: 72257;  load averages:  0.13,  0.09,  0.03    up 0+13:38:33  22:39:10
47 processes:  1 running, 46 sleeping
CPU states: 12.6% user,  0.0% nice,  7.8% system,  0.0% interrupt, 79.7% idle
Mem: 36M Active, 5256K Inact, 13M Wired, 6312K Cache, 15M Buf, 408K Free
Swap: 256M Total, 38M Used, 217M Free, 15% Inuse

  PID USERNAME PRI NICE  SIZE    RES STATE    TIME   WCPU    CPU COMMAND
72257 nik       28   0  1960K  1044K RUN      0:00 14.86%  1.42% top
 7078 nik        2   0 15280K 10960K select   2:54  0.88%  0.88% xemacs-21.1.14
  281 nik        2   0 18636K  7112K select   5:36  0.73%  0.73% XF86_SVGA
  296 nik        2   0  3240K  1644K select   0:12  0.05%  0.05% xterm
48630 nik        2   0 29816K  9148K select   3:18  0.00%  0.00% navigator-linu
  175 root       2   0   924K   252K select   1:41  0.00%  0.00% syslogd
 7059 nik        2   0  7260K  4644K poll     1:38  0.00%  0.00% mutt
...

The output is split into two sections. The header (the first five lines) shows the PID of the last process to run, the system load averages (which are a measure of how busy the system is), the system uptime (time since the last reboot) and the current time. The other figures in the header relate to how many processes are running (47 in this case), how much memory and swap space has been taken up, and how much time the system is spending in different CPU states.

Below that are a series of columns containing similar information to the output from ps(1). As before you can see the PID, the username, the amount of CPU time taken, and the command that was run. top(1) also defaults to showing you the amount of memory space taken by the process. This is split into two columns, one for total size, and one for resident size--total size is how much memory the application has needed, and the resident size is how much it is actually using at the moment. In this example you can see that Netscape® has required almost 30 MB of RAM, but is currently only using 9 MB.

top(1) automatically updates this display every two seconds; this can be changed with the s option.


3.8 Daemons, Signals, and Killing Processes

When you run an editor it is easy to control the editor, tell it to load files, and so on. You can do this because the editor provides facilities to do so, and because the editor is attached to a terminal. Some programs are not designed to be run with continuous user input, and so they disconnect from the terminal at the first opportunity. For example, a web server spends all day responding to web requests, it normally does not need any input from you. Programs that transport email from site to site are another example of this class of application.

We call these programs daemons. Daemons were characters in Greek mythology; neither good or evil, they were little attendant spirits that, by and large, did useful things for mankind. Much like the web servers and mail servers of today do useful things. This is why the BSD mascot has, for a long time, been the cheerful looking daemon with sneakers and a pitchfork.

There is a convention to name programs that normally run as daemons with a trailing ``d''. BIND is the Berkeley Internet Name Daemon (and the actual program that executes is called named), the Apache web server program is called httpd, the line printer spooling daemon is lpd and so on. This is a convention, not a hard and fast rule; for example, the main mail daemon for the Sendmail application is called sendmail, and not maild, as you might imagine.

Sometimes you will need to communicate with a daemon process. These communications are called signals, and you can communicate with a daemon (or with any other running process) by sending it a signal. There are a number of different signals that you can send--some of them have a specific meaning, others are interpreted by the application, and the application's documentation will tell you how that application interprets signals. You can only send a signal to a process that you own. If you send a signal to someone else's process with kill(1) or kill(2) permission will be denied. The exception to this is the root user, who can send signals to everyone's processes.

FreeBSD will also send applications signals in some cases. If an application is badly written, and tries to access memory that it is not supposed to, FreeBSD sends the process the Segmentation Violation signal (SIGSEGV). If an application has used the alarm(3) system call to be alerted after a period of time has elapsed then it will be sent the Alarm signal (SIGALRM), and so on.

Two signals can be used to stop a process, SIGTERM and SIGKILL. SIGTERM is the polite way to kill a process; the process can catch the signal, realize that you want it to shut down, close any log files it may have open, and generally finish whatever it is doing at the time before shutting down. In some cases a process may even ignore SIGTERM if it is in the middle of some task that can not be interrupted.

SIGKILL can not be ignored by a process. This is the ``I do not care what you are doing, stop right now'' signal. If you send SIGKILL to a process then FreeBSD will stop that process there and then[4].

The other signals you might want to use are SIGHUP, SIGUSR1, and SIGUSR2. These are general purpose signals, and different applications will do different things when they are sent.

Suppose that you have changed your web server's configuration file--you would like to tell the web server to re-read its configuration. You could stop and restart httpd, but this would result in a brief outage period on your web server, which may be undesirable. Most daemons are written to respond to the SIGHUP signal by re-reading their configuration file. So instead of killing and restarting httpd you would send it the SIGHUP signal. Because there is no standard way to respond to these signals, different daemons will have different behavior, so be sure and read the documentation for the daemon in question.

Signals are sent using the kill(1) command, as this example shows.

Sending a Signal to a Process

This example shows how to send a signal to inetd(8). The inetd configuration file is /etc/inetd.conf, and inetd will re-read this configuration file when it is sent SIGHUP.

  1. Find the process ID of the process you want to send the signal to. Do this using ps(1) and grep(1). The grep(1) command is used to search through output, looking for the string you specify. This command is run as a normal user, and inetd(8) is run as root, so the ax options must be given to ps(1).

    % ps -ax | grep inetd
      198  ??  IWs    0:00.00 inetd -wW
    

    So the inetd(8) PID is 198. In some cases the grep inetd command might also occur in this output. This is because of the way ps(1) has to find the list of running processes.

  2. Use kill(1) to send the signal. Because inetd(8) is being run by root you must use su(1) to become root first.

    % su
    Password:
    # /bin/kill -s HUP 198
    

    In common with most UNIX commands, kill(1) will not print any output if it is successful. If you send a signal to a process that you do not own then you will see ``kill: PID: Operation not permitted''. If you mistype the PID you will either send the signal to the wrong process, which could be bad, or, if you are lucky, you will have sent the signal to a PID that is not currently in use, and you will see ``kill: PID: No such process''.

    Why Use /bin/kill?: Many shells provide the kill command as a built in command; that is, the shell will send the signal directly, rather than running /bin/kill. This can be very useful, but different shells have a different syntax for specifying the name of the signal to send. Rather than try to learn all of them, it can be simpler just to use the /bin/kill ... command directly.

Sending other signals is very similar, just substitute TERM or KILL in the command line as necessary.

Important: Killing random process on the system can be a bad idea. In particular, init(8), process ID 1, is very special. Running /bin/kill -s KILL 1 is a quick way to shutdown your system. Always double check the arguments you run kill(1) with before you press Return.


3.9 Shells

In FreeBSD, a lot of everyday work is done in a command line interface called a shell. A shell's main job is to take commands from the input channel and execute them. A lot of shells also have built in functions to help everyday tasks such as file management, file globbing, command line editing, command macros, and environment variables. FreeBSD comes with a set of shells, such as sh, the Bourne Shell, and tcsh, the improved C-shell. Many other shells are available from the FreeBSD Ports Collection, such as zsh and bash.

Which shell do you use? It is really a matter of taste. If you are a C programmer you might feel more comfortable with a C-like shell such as tcsh. If you have come from Linux or are new to a UNIX command line interface you might try bash. The point is that each shell has unique properties that may or may not work with your preferred working environment, and that you have a choice of what shell to use.

One common feature in a shell is filename completion. Given the typing of the first few letters of a command or filename, you can usually have the shell automatically complete the rest of the command or filename by hitting the Tab key on the keyboard. Here is an example. Suppose you have two files called foobar and foo.bar. You want to delete foo.bar. So what you would type on the keyboard is: rm fo[Tab].[Tab].

The shell would print out rm foo[BEEP].bar.

The [BEEP] is the console bell, which is the shell telling me it was unable to totally complete the filename because there is more than one match. Both foobar and foo.bar start with fo, but it was able to complete to foo. If you type in ., then hit Tab again, the shell would be able to fill in the rest of the filename for you.

Another feature of the shell is the use of environment variables. Environment variables are a variable key pair stored in the shell's environment space. This space can be read by any program invoked by the shell, and thus contains a lot of program configuration. Here is a list of common environment variables and what they mean:

Variable Description
USER Current logged in user's name.
PATH Colon separated list of directories to search for binaries.
DISPLAY Network name of the X11 display to connect to, if available.
SHELL The current shell.
TERM The name of the user's terminal. Used to determine the capabilities of the terminal.
TERMCAP Database entry of the terminal escape codes to perform various terminal functions.
OSTYPE Type of operating system. e.g., FreeBSD.
MACHTYPE The CPU architecture that the system is running on.
EDITOR The user's preferred text editor.
PAGER The user's preferred text pager.
MANPATH Colon separated list of directories to search for manual pages.

Setting an environment variable differs somewhat from shell to shell. For example, in the C-Style shells such as tcsh and csh, you would use setenv to set environment variables. Under Bourne shells such as sh and bash, you would use export to set your current environment variables. For example, to set or modify the EDITOR environment variable, under csh or tcsh a command like this would set EDITOR to /usr/local/bin/emacs:

% setenv EDITOR /usr/local/bin/emacs

Under Bourne shells:

% export EDITOR="/usr/local/bin/emacs"

You can also make most shells expand the environment variable by placing a $ character in front of it on the command line. For example, echo $TERM would print out whatever $TERM is set to, because the shell expands $TERM and passes it on to echo.

Shells treat a lot of special characters, called meta-characters as special representations of data. The most common one is the * character, which represents any number of characters in a filename. These special meta-characters can be used to do filename globbing. For example, typing in echo * is almost the same as typing in ls because the shell takes all the files that match * and puts them on the command line for echo to see.

To prevent the shell from interpreting these special characters, they can be escaped from the shell by putting a backslash (\) character in front of them. echo $TERM prints whatever your terminal is set to. echo \$TERM prints $TERM as is.


3.9.1 Changing Your Shell

The easiest way to change your shell is to use the chsh command. Running chsh will place you into the editor that is in your EDITOR environment variable; if it is not set, you will be placed in vi. Change the ``Shell:'' line accordingly.

You can also give chsh the -s option; this will set your shell for you, without requiring you to enter an editor. For example, if you wanted to change your shell to bash, the following should do the trick:

% chsh -s /usr/local/bin/bash

Running chsh with no parameters and editing the shell from there would work also.

Note: The shell that you wish to use must be present in the /etc/shells file. If you have installed a shell from the ports collection, then this should have been done for you already. If you installed the shell by hand, you must do this.

For example, if you installed bash by hand and placed it into /usr/local/bin, you would want to:

# echo "/usr/local/bin/bash" >> /etc/shells

Then rerun chsh.


3.10 Text Editors

A lot of configuration in FreeBSD is done by editing text files. Because of this, it would be a good idea to become familiar with a text editor. FreeBSD comes with a few as part of the base system, and many more are available in the ports collection.

The easiest and simplest editor to learn is an editor called ee, which stands for easy editor. To start ee, one would type at the command line ee filename where filename is the name of the file to be edited. For example, to edit /etc/rc.conf, type in ee /etc/rc.conf. Once inside of ee, all of the commands for manipulating the editor's functions are listed at the top of the display. The caret ^ character represents the Ctrl key on the keyboard, so ^e expands to the key combination Ctrl+e. To leave ee, hit the Esc key, then choose leave editor. The editor will prompt you to save any changes if the file has been modified.

FreeBSD also comes with more powerful text editors such as vi as part of the base system, while other editors, like emacs and vim, are part of the FreeBSD Ports Collection. These editors offer much more functionality and power at the expense of being a little more complicated to learn. However if you plan on doing a lot of text editing, learning a more powerful editor such as vim or emacs will save you much more time in the long run.


3.11 Devices and Device Nodes

A device is a term used mostly for hardware-related activities in a system, including disks, printers, graphics cards, and keyboards. When FreeBSD boots, the majority of what FreeBSD displays are devices being detected. You can look through the boot messages again by viewing /var/run/dmesg.boot.

For example, acd0 is the first IDE CDROM drive, while kbd0 represents the keyboard.

Most of these devices in a UNIX operating system must be accessed through special files called device nodes, which are located in the /dev directory.


3.11.1 Creating Device Nodes

When adding a new device to your system, or compiling in support for additional devices, you may need to create one or more device nodes for the new devices.


3.11.1.1 MAKEDEV Script

On systems without DEVFS (this concerns all FreeBSD versions before 5.0), device nodes are created using the MAKEDEV(8) script as shown below:

# cd /dev
# sh MAKEDEV ad1
   

This example would make the proper device nodes for the second IDE drive when installed.


3.11.1.2 DEVFS (DEVice File System)

The device file system, or DEVFS, provides access to kernel's device namespace in the global file system namespace. Instead of having to create and modify device nodes, DEVFS maintains this particular file system for you.

See the devfs(5) manual page for more information.

DEVFS is used by default in FreeBSD 5.0 and above.


3.12 Binary Formats

To understand why FreeBSD uses the elf(5) format, you must first know a little about the three currently ``dominant'' executable formats for UNIX:

  • a.out(5)

    The oldest and ``classic'' UNIX object format. It uses a short and compact header with a magic number at the beginning that is often used to characterize the format (see a.out(5) for more details). It contains three loaded segments: .text, .data, and .bss plus a symbol table and a string table.

  • COFF

    The SVR3 object format. The header now comprises a section table, so you can have more than just .text, .data, and .bss sections.

  • elf(5)

    The successor to COFF, featuring multiple sections and 32-bit or 64-bit possible values. One major drawback: ELF was also designed with the assumption that there would be only one ABI per system architecture. That assumption is actually quite incorrect, and not even in the commercial SYSV world (which has at least three ABIs: SVR4, Solaris, SCO) does it hold true.

    FreeBSD tries to work around this problem somewhat by providing a utility for branding a known ELF executable with information about the ABI it is compliant with. See the manual page for brandelf(1) for more information.

FreeBSD comes from the ``classic'' camp and used the a.out(5) format, a technology tried and proven through many generations of BSD releases, until the beginning of the 3.X branch. Though it was possible to build and run native ELF binaries (and kernels) on a FreeBSD system for some time before that, FreeBSD initially resisted the ``push'' to switch to ELF as the default format. Why? Well, when the Linux camp made their painful transition to ELF, it was not so much to flee the a.out executable format as it was their inflexible jump-table based shared library mechanism, which made the construction of shared libraries very difficult for vendors and developers alike. Since the ELF tools available offered a solution to the shared library problem and were generally seen as ``the way forward'' anyway, the migration cost was accepted as necessary and the transition made. FreeBSD's shared library mechanism is based more closely on Sun's SunOS™ style shared library mechanism and, as such, is very easy to use.

So, why are there so many different formats?

Back in the dim, dark past, there was simple hardware. This simple hardware supported a simple, small system. a.out was completely adequate for the job of representing binaries on this simple system (a PDP-11). As people ported UNIX from this simple system, they retained the a.out format because it was sufficient for the early ports of UNIX to architectures like the Motorola 68k, VAXen, etc.

Then some bright hardware engineer decided that if he could force software to do some sleazy tricks, then he would be able to shave a few gates off the design and allow his CPU core to run faster. While it was made to work with this new kind of hardware (known these days as RISC), a.out was ill-suited for this hardware, so many formats were developed to get to a better performance from this hardware than the limited, simple a.out format could offer. Things like COFF, ECOFF, and a few obscure others were invented and their limitations explored before things seemed to settle on ELF.

In addition, program sizes were getting huge and disks (and physical memory) were still relatively small so the concept of a shared library was born. The VM system also became more sophisticated. While each one of these advancements was done using the a.out format, its usefulness was stretched more and more with each new feature. In addition, people wanted to dynamically load things at run time, or to junk parts of their program after the init code had run to save in core memory and swap space. Languages became more sophisticated and people wanted code called before main automatically. Lots of hacks were done to the a.out format to allow all of these things to happen, and they basically worked for a time. In time, a.out was not up to handling all these problems without an ever increasing overhead in code and complexity. While ELF solved many of these problems, it would be painful to switch from the system that basically worked. So ELF had to wait until it was more painful to remain with a.out than it was to migrate to ELF.

However, as time passed, the build tools that FreeBSD derived their build tools from (the assembler and loader especially) evolved in two parallel trees. The FreeBSD tree added shared libraries and fixed some bugs. The GNU folks that originally wrote these programs rewrote them and added simpler support for building cross compilers, plugging in different formats at will, and so on. Since many people wanted to build cross compilers targeting FreeBSD, they were out of luck since the older sources that FreeBSD had for as and ld were not up to the task. The new GNU tools chain (binutils) does support cross compiling, ELF, shared libraries, C++ extensions, etc. In addition, many vendors are releasing ELF binaries, and it is a good thing for FreeBSD to run them.

ELF is more expressive than a.out and allows more extensibility in the base system. The ELF tools are better maintained, and offer cross compilation support, which is important to many people. ELF may be a little slower than a.out, but trying to measure it can be difficult. There are also numerous details that are different between the two in how they map pages, handle init code, etc. None of these are very important, but they are differences. In time support for a.out will be moved out of the GENERIC kernel, and eventually removed from the kernel once the need to run legacy a.out programs is past.


3.13 For More Information

3.13.1 Manual Pages

The most comprehensive documentation on FreeBSD is in the form of manual pages. Nearly every program on the system comes with a short reference manual explaining the basic operation and various arguments. These manuals can be viewed with the man command. Use of the man command is simple:

% man command

command is the name of the command you wish to learn about. For example, to learn more about ls command type:

% man ls

The online manual is divided up into numbered sections:

  1. User commands.

  2. System calls and error numbers.

  3. Functions in the C libraries.

  4. Device drivers.

  5. File formats.

  6. Games and other diversions.

  7. Miscellaneous information.

  8. System maintenance and operation commands.

  9. Kernel developers.

In some cases, the same topic may appear in more than one section of the online manual. For example, there is a chmod user command and a chmod() system call. In this case, you can tell the man command which one you want by specifying the section:

% man 1 chmod

This will display the manual page for the user command chmod. References to a particular section of the online manual are traditionally placed in parenthesis in written documentation, so chmod(1) refers to the chmod user command and chmod(2) refers to the system call.

This is fine if you know the name of the command and simply wish to know how to use it, but what if you cannot recall the command name? You can use man to search for keywords in the command descriptions by using the -k switch:

% man -k mail

With this command you will be presented with a list of commands that have the keyword ``mail'' in their descriptions. This is actually functionally equivalent to using the apropos command.

So, you are looking at all those fancy commands in /usr/bin but do not have the faintest idea what most of them actually do? Simply do:

% cd /usr/bin
% man -f *

or

% cd /usr/bin
% whatis *

which does the same thing.


3.13.2 GNU Info Files

FreeBSD includes many applications and utilities produced by the Free Software Foundation (FSF). In addition to manual pages, these programs come with more extensive hypertext documents called info files which can be viewed with the info command or, if you installed emacs, the info mode of emacs.

To use the info(1) command, simply type:

% info

For a brief introduction, type h. For a quick command reference, type ?.


Chapter 4 Installing Applications: Packages and Ports

4.1 Synopsis

FreeBSD is bundled with a rich collection of system tools as part of the base system. However, there is only so much one can do before needing to install an additional third-party application to get real work done. FreeBSD provides two complementary technologies for installing third party software on your system: the FreeBSD Ports Collection, and binary software packages. Either system may be used to install the newest version of your favorite applications from local media or straight off the network.

After reading this chapter, you will know:

  • How to install third-party binary software packages.

  • How to build third-party software from the ports collection.

  • How to remove previously installed packages or ports.

  • How to override the default values that the ports collection uses.

  • How to upgrade your ports.


4.2 Overview of Software Installation

If you have used a UNIX system before you will know that the typical procedure for installing third party software goes something like this:

  1. Download the software, which might be distributed in source code format, or as a binary.

  2. Unpack the software from its distribution format (typically a tarball compressed with compress(1), gzip(1), or bzip2(1)).

  3. Locate the documentation (perhaps an INSTALL or README file, or some files in a doc/ subdirectory) and read up on how to install the software.

  4. If the software was distributed in source format, compile it. This may involve editing a Makefile, or running a configure script, and other work.

  5. Test and install the software.

And that is only if everything goes well. If you are installing a software package that was not deliberately ported to FreeBSD you may even have to go in and edit the code to make it work properly.

Should you want to, you can continue to install software the ``traditional'' way with FreeBSD. However, FreeBSD provides two technologies which can save you a lot of effort: packages and ports. At the time of writing, over 10,000 third party applications have been made available in this way.

For any given application, the FreeBSD package for that application is a single file which you must download. The package contains pre-compiled copies of all the commands for the application, as well as any configuration files or documentation. A downloaded package file can be manipulated with FreeBSD package management commands, such as pkg_add(1), pkg_delete(1), pkg_info(1), and so on. Installing a new application can be carried out with a single command.

A FreeBSD port for an application is a collection of files designed to automate the process of compiling an application from source code.

Remember that there are a number of steps you would normally carry out if you compiled a program yourself (downloading, unpacking, patching, compiling, installing). The files that make up a port contain all the necessary information to allow the system to do this for you. You run a handful of simple commands and the source code for the application is automatically downloaded, extracted, patched, compiled, and installed for you.

In fact, the ports system can also be used to generate packages which can later be manipulated with pkg_add and the other package management commands that will be introduced shortly.

Both packages and ports understand dependencies. Suppose you want to install an application that depends on a specific library being installed. Both the application and the library have been made available as FreeBSD ports and packages. If you use the pkg_add command or the ports system to add the application, both will notice that the library has not been installed, and automatically install the library first.

Given that the two technologies are quite similar, you might be wondering why FreeBSD bothers with both. Packages and ports both have their own strengths, and which one you use will depend on your own preference.

Package Benefits

  • A compressed package tarball is typically smaller than the compressed tarball containing the source code for the application.

  • Packages do not require any additional compilation. For large applications, such as Mozilla, KDE, or GNOME this can be important, particularly if you are on a slow system.

  • Packages do not require any understanding of the process involved in compiling software on FreeBSD.

Ports Benefits

  • Packages are normally compiled with conservative options, because they have to run on the maximum number of systems. By installing from the port, you can tweak the compilation options to (for example) generate code that is specific to a Pentium IV or Athlon processor.

  • Some applications have compile time options relating to what they can and cannot do. For example, Apache can be configured with a wide variety of different built-in options. By building from the port you do not have to accept the default options, and can set them yourself.

    In some cases, multiple packages will exist for the same application to specify certain settings. For example, Ghostscript is available as a ghostscript package and a ghostscript-nox11 package, depending on whether or not you have installed an X11 server. This sort of rough tweaking is possible with packages, but rapidly becomes impossible if an application has more than one or two different compile time options.

  • The licensing conditions of some software distributions forbid binary distribution. They must be distributed as source code.

  • Some people do not trust binary distributions. At least with source code, you can (in theory) read through it and look for potential problems yourself.

  • If you have local patches, you will need the source in order to apply them.

  • Some people like having code around, so they can read it if they get bored, hack it, borrow from it (license permitting, of course), and so on.

To keep track of updated ports, subscribe to the FreeBSD ports mailing list and the FreeBSD ports bugs mailing list.

The remainder of this chapter will explain how to use packages and ports to install and manage third party software on FreeBSD.


4.3 Finding Your Application

Before you can install any applications you need to know what you want, and what the application is called.

FreeBSD's list of available applications is growing all the time. Fortunately, there are a number of ways to find what you want:

  • The FreeBSD web site maintains an up-to-date searchable list of all the available applications, at http://www.FreeBSD.org/ports/. The ports are divided into categories, and you may either search for an application by name (if you know it), or see all the applications available in a category.

  • Dan Langille maintains FreshPorts, at http://www.FreshPorts.org/. FreshPorts tracks changes to the applications in the ports tree as they happen, allows you to ``watch'' one or more ports, and can send you email when they are updated.

  • If you do not know the name of the application you want, try using a site like FreshMeat (http://www.freshmeat.net/) to find an application, then check back at the FreeBSD site to see if the application has been ported yet.


4.4 Using the Packages System

Contributed by Chern Lee.

4.4.1 Installing a Package

You can use the pkg_add(1) utility to install a FreeBSD software package from a local file or from a server on the network.

Example 4-1. Downloading a Package Manually and Installing It Locally

# ftp -a ftp2.FreeBSD.org
Connected to ftp2.FreeBSD.org.
220 ftp2.FreeBSD.org FTP server (Version 6.00LS) ready.
331 Guest login ok, send your email address as password.
230-
230-     This machine is in Vienna, VA, USA, hosted by Verio.
230-         Questions? E-mail freebsd@vienna.verio.net.
230-
230-
230 Guest login ok, access restrictions apply.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> cd /pub/FreeBSD/ports/packages/sysutils/
250 CWD command successful.
ftp> get lsof-4.56.4.tgz
local: lsof-4.56.4.tgz remote: lsof-4.56.4.tgz
200 PORT command successful.
150 Opening BINARY mode data connection for 'lsof-4.56.4.tgz' (92375 bytes).
100% |**************************************************| 92375       00:00 ETA
226 Transfer complete.
92375 bytes received in 5.60 seconds (16.11 KB/s)
ftp> exit
# pkg_add lsof-4.56.4.tgz

If you do not have a source of local packages (such as a FreeBSD CD-ROM set) then it will probably be easier to use the -r option to pkg_add(1). This will cause the utility to automatically determine the correct object format and release and then fetch and install the package from an FTP site.

# pkg_add -r lsof

The example above would download the correct package and add it without any further user intervention. If you want to specify an alternative FreeBSD Packages Mirror, instead of the main distribution site, you have to set PACKAGESITE accordingly, to override the default settings. pkg_add(1) uses fetch(3) to download the files, which honors various environment variables, including FTP_PASSIVE_MODE, FTP_PROXY, and FTP_PASSWORD. You may need to set one or more of these if you are behind a firewall, or need to use an FTP/HTTP proxy. See fetch(3) for the complete list. Note that in the example above lsof is used instead of lsof-4.56.4. When the remote fetching feature is used, the version number of the package must be removed. pkg_add(1) will automatically fetch the latest version of the application.

Package files are distributed in .tgz and .tbz formats. You can find them at ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/packages/, or on the FreeBSD CD-ROM distribution. Every CD on the FreeBSD 4-CD set (and the PowerPak, etc.) contains packages in the /packages directory. The layout of the packages is similar to that of the /usr/ports tree. Each category has its own directory, and every package can be found within the All directory.

The directory structure of the package system matches the ports layout; they work with each other to form the entire package/port system.


4.4.2 Managing Packages

pkg_info(1) is a utility that lists and describes the various packages installed.

# pkg_info
cvsup-16.1          A general network file distribution system optimized for CV
docbook-1.2         Meta-port for the different versions of the DocBook DTD
...

pkg_version(1) is a utility that summarizes the versions of all installed packages. It compares the package version to the current version found in the ports tree.

# pkg_version
cvsup                       =
docbook                     =
...

The symbols in the second column indicate the relative age of the installed version and the version available in the local ports tree.

Symbol Meaning
= The version of the installed package matches the one found in the local ports tree.
< The installed version is older than the one available in the ports tree.
> The installed version is newer than the one found in the local ports tree. (The local ports tree is probably out of date.)
? The installed package cannot be found in the ports index. (This can happen, for instance, if an installed port is removed from the ports collection or renamed.)
* There are multiple versions of the package.

4.4.3 Deleting a Package

To remove a previously installed software package, use the pkg_delete(1) utility.

# pkg_delete xchat-1.7.1

4.4.4 Miscellaneous

All package information is stored within the /var/db/pkg directory. The installed file list and descriptions of each package can be found within files in this directory.


4.5 Using the Ports Collection

The following sections provide basic instructions on using the ports collection to install or remove programs from your system.


4.5.1 Obtaining the Ports Collection

Before you can install ports, you must first obtain the ports collection--which is essentially a set of Makefiles, patches, and description files placed in /usr/ports.

When installing your FreeBSD system, Sysinstall asked if you would like to install the ports collection. If you chose no, you can follow these instructions to obtain the ports collection:

Sysinstall Method

This method involves using sysinstall again to manually install the ports collection.

  1. As root, run /stand/sysinstall as shown below:

    # /stand/sysinstall
    
  2. Scroll down and select Configure, press Enter.

  3. Scroll down and select Distributions, press Enter.

  4. Scroll down to ports, press Space.

  5. Scroll up to Exit, press Enter.

  6. Select your desired installation media, such as CDROM, FTP, and so on.

  7. Scroll up to Exit and press Enter.

  8. Press X to exit sysinstall.

The alternative method to obtain and keep your ports collection up to date is by using CVSup. Look at the ports CVSup file, /usr/share/examples/cvsup/ports-supfile. See Using CVSup (Section A.5) for more information on using CVSup and this file.

CVSup Method

This is a quick method for getting the ports collection using CVSup. If you want to keep your ports tree up to date, or learn more about CVSup, read the previously mentioned sections.

  1. Install the net/cvsup port. See CVSup Installation (Section A.5.2) for more details.

  2. As root, copy /usr/share/examples/cvsup/ports-supfile to a new location, such as /root or your home directory.

  3. Edit ports-supfile.

  4. Change CHANGE_THIS.FreeBSD.org to a CVSup server near you. See CVSup Mirrors (Section A.5.7) for a complete listing of mirror sites.

  5. Run cvsup:

    # cvsup -g -L 2 /root/ports-supfile
    
  6. Running this command later will download and apply all the recent changes to your ports collection, except actually rebuilding the ports for your own system.


4.5.2 Installing Ports

The first thing that should be explained when it comes to the ports collection is what is actually meant by a ``skeleton''. In a nutshell, a port skeleton is a minimal set of files that tell your FreeBSD system how to cleanly compile and install a program. Each port skeleton includes:

  • A Makefile. The Makefile contains various statements that specify how the application should be compiled and where it should be installed on your system.

  • A distinfo file. This file contains information about the files that must be downloaded to build the port and their checksums, to verify that files have not been corrupted during the download using md5(1).

  • A files directory. This directory contains patches to make the program compile and install on your FreeBSD system. Patches are basically small files that specify changes to particular files. They are in plain text format, and basically say ``Remove line 10'' or ``Change line 26 to this ...''. Patches are also known as ``diffs'' because they are generated by the diff(1) program.

    This directory may also contain other files used to build the port.

  • A pkg-descr file. This is a more detailed, often multiple-line, description of the program.

  • A pkg-plist file. This is a list of all the files that will be installed by the port. It also tells the ports system what files to remove upon deinstallation.

Some ports have other files, such as pkg-message. The ports system uses these files to handle special situations. If you want more details on these files, and on ports in general, check out the FreeBSD Porter's Handbook.

Now that you have enough background information to know what the ports collection is used for, you are ready to install your first port. There are two ways this can be done, and each is explained below.

Before we get into that, however, you will need to choose a port to install. There are a few ways to do this, with the easiest method being the ports listing on the FreeBSD web site. You can browse through the ports listed there or use the search function on the site. Each port also includes a description so you can read a bit about each port before deciding to install it.

Another method is to use the whereis(1) command. Simply type whereis file, where file is the program you want to install. If it is found on your system, you will be told where it is, as follows:

# whereis lsof
lsof: /usr/ports/sysutils/lsof

This tells us that lsof (a system utility) can be found in the /usr/ports/sysutils/lsof directory.

Yet another way to find a particular port is by using the ports collection's built-in search mechanism. To use the search feature, you will need to be in the /usr/ports directory. Once in that directory, run make search name=program-name where program-name is the name of the program you want to find. For example, if you were looking for lsof:

# cd /usr/ports
# make search name=lsof
Port:   lsof-4.56.4
Path:   /usr/ports/sysutils/lsof
Info:   Lists information about open files (similar to fstat(1))
Maint:  obrien@FreeBSD.org
Index:  sysutils
B-deps: 
R-deps:

The part of the output you want to pay particular attention to is the ``Path:'' line, since that tells you where to find the port. The other information provided is not needed in order to install the port, so it will not be covered here.

For more in-depth searching you can also use make search key=string where string is some text to search for. This searches port names, comments, descriptions and dependencies and can be used to find ports which relate to a particular subject if you don't know the name of the program you are looking for.

In both of these cases, the search string is case-insensitive. Searching for ``LSOF'' will yield the same results as searching for ``lsof''.

Note: You must be logged in as root to install ports.

Now that you have found a port you would like to install, you are ready to do the actual installation. The port includes instructions on how to build source code, but does not include the actual source code. You can get the source code from a CD-ROM or from the Internet. Source code is distributed in whatever manner the software author desires. Frequently this is a tarred and gzipped file, but it might be compressed with some other tool or even uncompressed. The program source code, whatever form it comes in, is called a ``distfile''. You can get the distfile from a CD-ROM or from the Internet.


4.5.2.1 Installing Ports from a CD-ROM

The FreeBSD Project's official CD-ROM images no longer include distfiles. They take up a lot of room that is better used for precompiled packages. CD-ROM products such as the FreeBSD PowerPak do include distfiles, and you can order these sets from a vendor such as the FreeBSD Mall. This section assumes you have such a FreeBSD CD-ROM set.

Place your FreeBSD CD-ROM in the drive. Mount it on /cdrom. (If you use a different mount point, the install will not work.) To begin, change to the directory for the port you want to install:

# cd /usr/ports/sysutils/lsof

Once inside the lsof directory, you will see the port skeleton. The next step is to compile, or ``build'', the port. This is done by simply typing make at the prompt. Once you have done so, you should see something like this:

# make
>> lsof_4.57D.freebsd.tar.gz doesn't seem to exist in /usr/ports/distfiles/.
>> Attempting to fetch from file:/cdrom/ports/distfiles/.
===>  Extracting for lsof-4.57
...
[extraction output snipped]
...
>> Checksum OK for lsof_4.57D.freebsd.tar.gz.
===>  Patching for lsof-4.57
===>  Applying FreeBSD patches for lsof-4.57
===>  Configuring for lsof-4.57
...
[configure output snipped]
...
===>  Building for lsof-4.57
...
[compilation output snipped]
...
#

Notice that once the compile is complete you are returned to your prompt. The next step is to install the port. In order to install it, you simply need to tack one word onto the make command, and that word is install:

# make install
===>  Installing for lsof-4.57
...
[installation output snipped]
...
===>   Generating temporary packing list
===>   Compressing manual pages for lsof-4.57
===>   Registering installation for lsof-4.57
===>  SECURITY NOTE: 
      This port has installed the following binaries which execute with
      increased privileges.
#

Once you are returned to your prompt, you should be able to run the application you just installed. Since lsof is a program that runs with increased privileges, a security warning is shown. During the building and installation of ports, you should take heed of any other warnings that may appear.

Note: You can save an extra step by just running make install instead of make and make install as two separate steps.

Note: Some shells keep a cache of the commands that are available in the directories listed in the PATH environment variable, to speed up lookup operations for the executable file of these commands. If you are using one of these shells, you might have to use the rehash command after installing a port, before the newly installed commands can be used. This is true for both shells that are part of the base-system (such as tcsh) and shells that are available as ports (for instance, shells/zsh).

Note: Please be aware that the licenses of a few ports do not allow for inclusion on the CD-ROM. This could be because a registration form needs to be filled out before downloading or redistribution is not allowed, or for another reason. If you wish to install a port not included on the CD-ROM, you will need to be online in order to do so (see the next section).


4.5.2.2 Installing Ports from the Internet

As with the last section, this section makes an assumption that you have a working Internet connection. If you do not, you will need to perform the CD-ROM installation, or put a copy of the distfile into /usr/ports/distfiles manually.

Installing a port from the Internet is done exactly the same way as it would be if you were installing from a CD-ROM. The only difference between the two is that the distfile is downloaded from the Internet instead of read from the CD-ROM.

The steps involved are identical:

# make install
>> lsof_4.57D.freebsd.tar.gz doesn't seem to exist in /usr/ports/distfiles/.
>> Attempting to fetch from ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/distfiles/.
Receiving lsof_4.57D.freebsd.tar.gz (439860 bytes): 100%
439860 bytes transferred in 18.0 seconds (23.90 kBps)
===>  Extracting for lsof-4.57
...
[extraction output snipped]
...
>> Checksum OK for lsof_4.57D.freebsd.tar.gz.
===>  Patching for lsof-4.57
===>  Applying FreeBSD patches for lsof-4.57
===>  Configuring for lsof-4.57
...
[configure output snipped]
...
===>  Building for lsof-4.57
...
[compilation output snipped]
...
===>  Installing for lsof-4.57
...
[installation output snipped]
...
===>   Generating temporary packing list
===>   Compressing manual pages for lsof-4.57
===>   Registering installation for lsof-4.57
===>  SECURITY NOTE: 
      This port has installed the following binaries which execute with
      increased privileges.
#

As you can see, the only difference is the line that tells you where the system is fetching the port distfile from.

The ports system uses fetch(1) to download the files, which honors various environment variables, including FTP_PASSIVE_MODE, FTP_PROXY, and FTP_PASSWORD. You may need to set one or more of these if you are behind a firewall, or need to use an FTP/HTTP proxy. See fetch(3) for the complete list.

For users which cannot be connected all the time, the make fetch option is provided. Just run this command at the top level directory (/usr/ports) and the required files will be downloaded for you. This command will also work in the lower level categories, for example: /usr/ports/net. Note that if a port depends on libraries or other ports this will not fetch the distfiles of those ports too. Replace fetch with fetch-recursive if you want to fetch all the dependencies of a port too.

Note: You can build all the ports in a category or as a whole by running make in the top level directory, just like the aforementioned make fetch method. This is dangerous, however, as some ports cannot co-exist. In other cases, some ports can install two different files with the same filename.

In some rare cases, users may need to acquire the tarballs from a site other than the MASTER_SITES (the location where files are downloaded from). You can override the MASTER_SITES option with the following command:

# cd /usr/ports/directory
# make MASTER_SITE_OVERRIDE= \
    ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/distfiles/ fetch

In this example we change the MASTER_SITES option to ftp.FreeBSD.org/pub/FreeBSD/ports/distfiles/.

Note: Some ports allow (or even require) you to provide build options which can enable/disable parts of the application which are unneeded, certain security options, and other customizations. A few which come to mind are www/mozilla, security/gpgme, and mail/sylpheed-claws. A message will be displayed when options such as these are available.


4.5.2.3 Overriding the Default Ports Directories

Sometimes it is useful (or mandatory) to use a different distfiles and ports directory. The PORTSDIR and PREFIX variables can override the default directories. For example:

# make PORTSDIR=/usr/home/example/ports install

will compile the port in /usr/home/example/ports and install everything under /usr/local.

# make PREFIX=/usr/home/example/local install

will compile it in /usr/ports and install it in /usr/home/example/local.

And of course,

# make PORTSDIR=../ports PREFIX=../local install

will combine the two (it is too long to completely write on this page, but it should give you the general idea).

Alternatively, these variables can also be set as part of your environment. Read the manual page for your shell for instructions on doing so.


4.5.2.4 Dealing with imake

Some ports that use imake (a part of the X Windows System) do not work well with PREFIX, and will insist on installing under /usr/X11R6. Similarly, some Perl ports ignore PREFIX and install in the Perl tree. Making these ports respect PREFIX is a difficult or impossible job.


4.5.3 Removing Installed Ports

Now that you know how to install ports, you are probably wondering how to remove them, just in case you install one and later on decide that you installed the wrong port. We will remove our previous example (which was lsof for those of you not paying attention). As with installing ports, the first thing you must do is change to the port directory, /usr/ports/sysutils/lsof. After you change directories, you are ready to uninstall lsof. This is done with the make deinstall command:

# cd /usr/ports/sysutils/lsof
# make deinstall
===>  Deinstalling for lsof-4.57

That was easy enough. You have removed lsof from your system. If you would like to reinstall it, you can do so by running make reinstall from the /usr/ports/sysutils/lsof directory.

The make deinstall and make reinstall sequence does not work once you have run make clean. If you want to deinstall a port after cleaning, use pkg_delete(1) as discussed in the Packages section of the Handbook.


4.5.4 Ports and Disk Space

Using the ports collection can defiantly eat up your disk space. For this reason you should always remember to clean up the work directories using the make clean option. This will remove the work directory after a port has been built, and installed. You can also remove the tar files from the distfiles directory, and remove the installed ports when their use has delimited.

Some users choose to limit the port categories by placing an entry in the refuse file. This way when they run the CVSup application, it will not download the files in that category.


4.5.5 Upgrading Ports

Keeping your ports up to date can be a tedious job. For instance, to upgrade a port you would go to the ports directory, build the port, deinstall the old port, install the new port, and then clean up after the build. Imagine doing that for five ports, tedious right? This was a large problem for system administrators to deal with, and now we have utilities which do this for us. For instance the sysutils/portupgrade utility will do everything for you! Just install it like you would any other port, using the make install clean command.

Now create a database with the pkgdb -F command. This will read the list of installed ports and create a database file in the /var/db/pkg directory. Now when you run portupgrade -a, it will read this and the ports INDEX file. Finally, portupgrade will begin to download, build, backup, install, and clean the ports which have been updated. portupgrade comes with a lot of options for different use cases, the most important ones will be presented below:

If you want to upgrade only a certain application, not the complete database, use portupgrade pkgname, include the flags -r if portupgrade should act on all those packages depending on the given package as well, and -R to act on all packages required by the given packages. To use packages instead of ports for installation, provide -P and to just fetch distfiles without building or installing anything, use -F. For further information see portupgrade(1).

Note: It is important to regularly update the package database using pkgdb -F to fix inconsistencies, especially when portupgrade asks you to. Do not abort portupgrade while it is updating the package database, this will leave you an inconsistent database.

Other utilities exist which will do this, check out the ports/sysutils directory and see what you come up with.


4.6 Post-installation Activities

After installing a new application you will normally want to read any documentation it may have included, edit any configuration files that are required, ensure that the application starts at boot time (if it is a daemon), and so on.

The exact steps you need to take to configure each application will obviously be different. However, if you have just installed a new application and are wondering ``What now?'' these tips might help:

  • Use pkg_info(1) to find out which files were installed, and where. For example, if you have just installed FooPackage version 1.0.0, then this command

    # pkg_info -L foopackage-1.0.0 | less
    

    will show all the files installed by the package. Pay special attention to files in man/ directories, which will be manual pages, etc/ directories, which will be configuration files, and doc/, which will be more comprehensive documentation.

    If you are not sure which version of the application was just installed, a command like this

    # pkg_info | grep -i foopackage
    

    will find all the installed packages that have foopackage in the package name. Replace foopackage in your command line as necessary.

  • Once you have identified where the application's manual pages have been installed, review them using man(1). Similarly, look over the sample configuration files, and any additional documentation that may have been provided.

  • If the application has a web site, check it for additional documentation, frequently asked questions, and so forth. If you are not sure of the web site address it may be listed in the output from

    # pkg_info foopackage-1.0.0
    

    A WWW: line, if present, should provide a URL for the application's web site.

  • Ports that should start at boot (such as Internet servers) will usually install a sample script in /usr/local/etc/rc.d. You should review this script for correctness and edit or rename it if needed. See Starting Services for more information.


4.7 Dealing with Broken Ports

If you come across a port that does not work for you, there are a few things you can do, including:

  1. Fix it! The Porter's Handbook includes detailed information on the ``Ports'' infrastructure so that you can fix the occasional broken port or even submit your own!

  2. Gripe--by email only! Send email to the maintainer of the port first. Type make maintainer or read the Makefile to find the maintainer's email address. Remember to include the name and version of the port (send the $FreeBSD: line from the Makefile) and the output leading up to the error when you email the maintainer. If you do not get a response from the maintainer, you can use send-pr(1) to submit a bug report.

  3. Grab the package from an FTP site near you. The ``master'' package collection is on ftp.FreeBSD.org in the packages directory, but be sure to check your local mirror first! These are more likely to work than trying to compile from source and are a lot faster as well. Use the pkg_add(1) program to install the package on your system.


Chapter 5 The X Window System

5.1 Synopsis

FreeBSD uses XFree86 to provide users with a powerful graphical user interface. XFree86 is an open-source implementation of the X Window System. This chapter will cover installation and configuration of XFree86 on a FreeBSD system. For more information on XFree86 and video hardware that it supports, check the XFree86 web site.

After reading this chapter, you will know:

  • The various components of the X Window System, and how they interoperate.

  • How to install and configure XFree86.

  • How to install and use different window managers.

  • How to use TrueType® fonts in XFree86.

  • How to set up your system for graphical logins (XDM).

Before reading this chapter, you should:

  • Know how to install additional third-party software (Chapter 4).


5.2 Understanding X

Using X for the first time can be somewhat of a shock to someone familiar with other graphical environments, such as Microsoft Windows or Mac OS.

It is not necessary to understand all of the details of various X components and how they interact; however, some basic knowledge makes it possible to take advantage of X's strengths.


5.2.1 Why X?

X is not the first window system written for UNIX, but it is the most popular. X's original development team had worked on another window system before writing X. That system's name was ``W'' (for ``Window''). X is just the next letter in the Roman alphabet.

X can be called ``X'', ``X Window System'', ``X11'', and other terms. Calling X11 ``X Windows'' can offend some people; see X(7) for a bit more insight on this.


5.2.2 The X Client/Server Model

X was designed from the beginning to be network-centric, and adopts a ``client-server'' model. In the X model, the ``X server'' runs on the computer that has the keyboard, monitor, and mouse attached. The server is responsible for managing the display, handling input from the keyboard and mouse, and so on. Each X application (such as XTerm, or Netscape) is a ``client''. A client sends messages to the server such as ``Please draw a window at these coordinates'', and the server sends back messages such as ``The user just clicked on the OK button''.

If there is only one computer involved, such as in a home or small office environment, the X server and the X clients will be running on the same computer. However, it is perfectly possible to run the X server on a less powerful desktop computer, and run X applications (the clients) on, say, the powerful and expensive machine that serves the office. In this scenario the communication between the X client and server takes place over the network.

This confuses some people, because the X terminology is exactly backward to what they expect. They expect the ``X server'' to be the big powerful machine down the hall, and the ``X client'' to be the machine on their desk.

Remember that the X server is the machine with the monitor and keyboard, and the X clients are the programs that display the windows.

There is nothing in the protocol that forces the client and server machines to be running the same operating system, or even to be running on the same type of computer. It is certainly possible to run an X server on Microsoft Windows or Apple's Mac OS, and there are various free and commercial applications available that do exactly that.

The X server that ships with FreeBSD is called XFree86, and is available for free, under a license very similar to the FreeBSD license. Commercial X servers for FreeBSD are also available.


5.2.3 The Window Manager

The X design philosophy is much like the UNIX design philosophy, ``tools, not policy''. This means that X does not try to dictate how a task is to be accomplished. Instead, tools are provided to the user, and it is the user's responsibility to decide how to use those tools.

This philosophy extends to X not dictating what windows should look like on screen, how to move them around with the mouse, what keystrokes should be used to move between windows (i.e., Alt+Tab, in the case of Microsoft Windows), what the title bars on each window should look like, whether or not they have close buttons on them, and so on.

Instead, X delegates this responsibility to an application called a ``Window Manager''. There are dozens of window managers available for X: AfterStep, Blackbox, ctwm, Enlightenment, fvwm, Sawfish, twm, Window Maker, and more. Each of these window managers provides a different look and feel; some of them support ``virtual desktops''; some of them allow customized keystrokes to manage the desktop; some have a ``Start'' button or similar device; some are ``themeable'', allowing a complete change of look-and-feel by applying a new theme. These window managers, and many more, are available in the x11-wm category of the Ports Collection.

In addition, the KDE and GNOME desktop environments both have their own window managers which integrate with the desktop.

Each window manager also has a different configuration mechanism; some expect configuration file written by hand, others feature GUI tools for most of the configuration tasks; at least one (sawfish) has a configuration file written in a dialect of the Lisp language.

Focus Policy: Another feature the window manager is responsible for is the mouse ``focus policy''. Every windowing system needs some means of choosing a window to be actively receiving keystrokes, and should visibly indicate which window is active as well.

A familiar focus policy is called ``click-to-focus''. This is the model utilized by Microsoft Windows, in which a window becomes active upon receiving a mouse click.

X does not support any particular focus policy. Instead, the window manager controls which window has the focus at any one time. Different window managers will support different focus methods. All of them support click to focus, and the majority of them support several others.

The most popular focus policies are:

focus-follows-mouse

The window that is under the mouse pointer is the window that has the focus. This may not necessarily be the window that is on top of all the other windows. The focus is changed by pointing at another window, there is no need to click in it as well.

sloppy-focus

This policy is a small extension to focus-follows-mouse. With focus-follows-mouse, if the mouse is moved over the root window (or background) then no window has the focus, and keystrokes are simply lost. With sloppy-focus, focus is only changed when the cursor enters a new window, and not when exiting the current window.

click-to-focus

The active window is selected by mouse click. The window may then be ``raised'', and appear in front of all other windows. All keystrokes will now be directed to this window, even if the cursor is moved to another window.

Many window managers support other policies, as well as variations on these. Be sure to consult the documentation for the window manager itself.


5.2.4 Widgets

The X approach of providing tools and not policy extends to the widgets seen on screen in each application.

``Widget'' is a term for all the items in the user interface that can be clicked or manipulated in some way; buttons, check boxes, radio buttons, icons, lists, and so on. Microsoft Windows calls these ``controls''.

Microsoft Windows and Apple's Mac OS both have a very rigid widget policy. Application developers are supposed to ensure that their applications share a common look and feel. With X, it was not considered sensible to mandate a particular graphical style, or set of widgets to adhere to.

As a result, do not expect X applications to have a common look and feel. There are several popular widget sets and variations, including the original Athena widget set from MIT, Motif® (on which the widget set in Microsoft Windows was modeled, all bevelled edges and three shades of grey), OpenLook, and others.

Most newer X applications today will use a modern-looking widget set, either Qt, used by KDE, or GTK, used by the GNOME project. In this respect, there is some convergence in look-and-feel of the UNIX desktop, which certainly makes things easier for the novice user.


5.3 Installing XFree86

Before installing XFree86, decide on which version to run. XFree86 3.X is a maintenance branch of XFree86 development. It is very stable, and it supports a huge number of graphics cards. However, no new development is being done on the software. XFree86 4.X is a complete redesign of the system with many new features such as better support for fonts and anti-aliasing. Unfortunately this new architecture requires that the video drivers be rewritten, and some of the older cards that were supported in 3.X are not yet supported in 4.X. As all new developments and support for new graphics cards are done on that branch, XFree86 4.X is now the default version of the X Window System on FreeBSD.

The FreeBSD setup program offers users the opportunity to install and configure XFree86 4.X during installation (covered in Section 2.9.12). To install and run XFree86 3.X, wait until after the base FreeBSD system is installed, and then install XFree86. For example, to build and install XFree86 3.X from the ports collection:

# cd /usr/ports/x11/XFree86
# make all install clean

Alternatively, either version of XFree86 can be installed directly from the FreeBSD binaries provided on the XFree86 web site. A binary package to use with pkg_add(1) tool is also available for XFree86 4.X. When the remote fetching feature of pkg_add(1) is used, the version number of the package must be removed. pkg_add(1) will automatically fetch the latest version of the application. So to fetch and install the package of XFree86 4.X, simply type:

# pkg_add -r XFree86

You can also use the ports collection to install XFree86 4.X, for that you simply need to type the following commands:

# cd /usr/ports/x11/XFree86-4
# make install clean

Note: The examples above will install the complete XFree86 distribution including the servers, clients, fonts etc. Separate packages and ports for different parts of XFree86 4.X are also available.

The rest of this chapter will explain how to configure XFree86, and how to set up a productive desktop environment.


5.4 XFree86 Configuration

Contributed by Christopher Shumway.

5.4.1 Before Starting

Before configuration of XFree86 4.X, the following information about the target system is needed:

  • Monitor specifications

  • Video Adapter chipset

  • Video Adapter memory

The specifications for the monitor are used by XFree86 to determine the resolution and refresh rate to run at. These specifications can usually be obtained from the documentation that came with the monitor or from the manufacturer's website. There are two ranges of numbers that are needed, the horizontal scan rate and the vertical synchronization rate.

The video adapter's chipset defines what driver module XFree86 uses to talk to the graphics hardware. With most chipsets, this can be automatically determined, but it is still useful to know in case the automatic detection does not work correctly.

Video memory on the graphic adapter determines the resolution and color depth which the system can run at. This is important to know so the user knows the limitations of the system.


5.4.2 Configuring XFree86 4.X

Configuration of XFree86 4.X is a multi-step process. The first step is to build an initial configuration file with the -configure option to XFree86. As the super user, simply run:

# XFree86 -configure

This will generate a skeleton XFree86 configuration file in the /root directory called XF86Config.new (in fact the directory used is the one covered by the environment variable $HOME, and it will depend from the way you got the superuser rights). The XFree86 program will attempt to probe the graphics hardware on the system and will write a configuration file to load the proper drivers for the detected hardware on the target system.

The next step is to test the existing configuration to verify that XFree86 can work with the graphics hardware on the target system. To perform this task, the user needs to run:

# XFree86 -xf86config XF86Config.new

If a black and grey grid and an X mouse cursor appear, the configuration was successful. To exit the test, just press Ctrl+Alt+Backspace simultaneously.

Note: If the mouse does not work, be sure the device has been configured. See Section 2.9.10 in the FreeBSD install chapter.

Next, tune the XF86Config.new configuration file to taste. Open the file in a text editor such as emacs(1) or ee(1). First, add the frequencies for the target system's monitor. These are usually expressed as a horizontal and vertical synchronization rate. These values are added to the XF86Config.new file under the "Monitor" section:

Section "Monitor"
        Identifier   "Monitor0"
        VendorName   "Monitor Vendor"
        ModelName    "Monitor Model"
        HorizSync    30-107
        VertRefresh  48-120
EndSection

The HorizSync and VertRefresh keywords may not exist in the configuration file. If they do not, they need to be added, with the correct horizontal synchronization rate placed after the HorizSync keyword and the vertical synchronization rate after the VertRefresh keyword. In the example above the target monitor's rates were entered.

X allows DPMS (Energy Star) features to be used with capable monitors. The xset(1) program controls the time-outs and can force standby, suspend, or off modes. If you wish to enable DPMS features for your monitor, you must add the following line to the monitor section:

        Option       "DPMS"

While the XF86Config.new configuration file is still open in an editor, select the default resolution and color depth desired. This is defined in the "Screen" section:

Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
        Monitor    "Monitor0"
        DefaultDepth 24
        SubSection "Display"
                Depth     24
                Modes     "1024x768"
        EndSubSection
EndSection

The DefaultDepth keyword describes the color depth to run at by default. This can be overridden with the -bpp command line switch to XFree86(1). The Modes keyword describes the resolution to run at for the given color depth. Note that only VESA standard modes are supported as defined by the target system's graphics hardware. In the example above, the default color depth is twenty-four bits per pixel. At this color depth, the accepted resolution is one thousand twenty-four pixels by seven hundred and sixty-eight pixels.

Finally, write the configuration file and test it using the test mode given above. If all is well, the configuration file needs to be installed in a common location where XFree86(1) can find it. This is typically /etc/X11/XF86Config or /usr/X11R6/etc/X11/XF86Config.

# cp XF86Config.new /etc/X11/XF86Config

Once the configuration file has been placed in a common location, configuration is complete. In order to start XFree86 4.X with startx(1), install the x11/wrapper port. XFree86 4.X can also be started with xdm(1).

Note: There is also a graphical tool for configuration, xf86cfg(1), that comes with the XFree86 4.X distribution. It allows to interactively define your configuration by choosing the appropriate drivers and settings. This program can be used under console as well, just use the command xf86cfg -textmode. For more details, refer to the xf86cfg(1) manual page.


5.4.3 Advanced Configuration Topics

5.4.3.1 Configuration with Intel® i810 Graphics Chipsets

Configuration with Intel i810 integrated chipsets requires the agpgart AGP programming interface for XFree86 to drive the card. The agp(4) driver is in the GENERIC kernel since releases 4.8-RELEASE and 5.0-RELEASE. On prior releases, you will have to add the following line:

device agp

in your kernel configuration file and rebuild a new kernel. Instead, you may want to load the agp.ko kernel module automatically with the loader(8) at boot time. For that, simply add this line to /boot/loader.conf:

agp_load="YES"

Next, if you are running FreeBSD 4.X or earlier, a device node needs to be created for the programming interface. To create the AGP device node, run MAKEDEV(8) in the /dev directory:

# cd /dev
# sh MAKEDEV agpgart

Note: FreeBSD 5.X or later will use devfs(5) to allocate device nodes transparently, therefore the MAKEDEV(8) step is not required.

This will allow configuration of the hardware as any other graphics board. Note on systems without the agp(4) driver compiled in the kernel, trying to load the module with kldload(8) will not work. This driver has to be in the kernel at boot time through being compiled in or using /boot/loader.conf.

If you are using XFree86 4.1.0 (or later) and messages about unresolved symbols like fbPictureInit appear, try adding the following line after Driver "i810" in the XFree86 configuration file:

Option "NoDDC"

5.5 Using Fonts in XFree86

Contributed by Murray Stokely.

5.5.1 Type1 Fonts

The default fonts that ship with XFree86 are less than ideal for typical desktop publishing applications. Large presentation fonts show up jagged and unprofessional looking, and small fonts in Netscape are almost completely unintelligible. However, there are several free, high quality Type1 (PostScript®) fonts available which can be readily used with XFree86, either version 3.X or version 4.X. For instance, the URW font collection (x11-fonts/urwfonts) includes high quality versions of standard type1 fonts (Times Roman®, Helvetica®, Palatino® and others). The Freefonts collection (x11-fonts/freefonts) includes many more fonts, but most of them are intended for use in graphics software such as the Gimp, and are not complete enough to serve as screen fonts. In addition, XFree86 can be configured to use TrueType fonts with a minimum of effort: see the section on TrueType fonts later.

To install the above Type1 font collections from the ports collection, run the following commands:

# cd /usr/ports/x11-fonts/urwfonts
# make install clean

And likewise with the freefont or other collections. To tell the X server that these fonts exist, add an appropriate line to the XF86Config file (in /etc/ for XFree86 version 3, or in /etc/X11/ for version 4), which reads:

FontPath "/usr/X11R6/lib/X11/fonts/URW/"

Alternatively, at the command line in the X session run:

% xset fp+ /usr/X11R6/lib/X11/fonts/URW
% xset fp rehash

This will work but will be lost when the X session is closed, unless it is added to the startup file (~/.xinitrc for a normal startx session, or ~/.xsession when logging in through a graphical login manager like XDM). A third way is to use the new XftConfig file: see the section on anti-aliasing.


5.5.2 TrueType® Fonts

XFree86 4.X has built in support for rendering TrueType fonts. There are two different modules that can enable this functionality. The freetype module is used in this example because it is more consistent with the other font rendering back-ends. To enable the freetype module just add the following line to the "Module" section of the /etc/X11/XF86Config file.

Load  "freetype"

For XFree86 3.3.X, a separate TrueType font server is needed. Xfstt is commonly used for this purpose. To install Xfstt, simply install the port x11-servers/Xfstt.

Now make a directory for the TrueType fonts (for example, /usr/X11R6/lib/X11/fonts/TrueType) and copy all of the TrueType fonts into this directory. Keep in mind that TrueType fonts cannot be directly taken from a Macintosh®; they must be in UNIX/DOS/Windows format for use by XFree86. Once the files have been copied into this directory, use ttmkfdir to create a fonts.dir file, so that the X font renderer knows that these new files have been installed. ttmkfdir is available from the FreeBSD Ports Collection as x11-fonts/ttmkfdir.

# cd /usr/X11R6/lib/X11/fonts/TrueType
# ttmkfdir > fonts.dir

Now add the TrueType directory to the font path. This is just the same as described above for Type1 fonts, that is, use

% xset fp+ /usr/X11R6/lib/X11/fonts/TrueType
% xset fp rehash

or add a FontPath line to the XF86Config file.

That's it. Now Netscape, Gimp, StarOffice, and all of the other X applications should now recognize the installed TrueType fonts. Extremely small fonts (as with text in a high resolution display on a web page) and extremely large fonts (within StarOffice) will look much better now.


5.5.3 Anti-Aliased Fonts

Updated for XFree86 4.3 by Joe Marcus Clarke.

Anti-aliasing has been available in XFree86 since 4.0.2. However, font configuration was cumbersome before the introduction of XFree86 4.3.0. Starting in version 4.3.0, all fonts in /usr/X11R6/lib/X11/fonts/ and ~/.fonts/ are automatically made available for anti-aliasing to Xft-aware applications. Not all applications are Xft-aware yet, but many have received Xft support. Examples of Xft-aware applications include Qt 2.3 and higher (the toolkit for the KDE desktop), Gtk+ 2.0 and higher (the toolkit for the GNOME desktop), and Mozilla 1.2 and higher.

In order to control which fonts are anti-aliased, or to configure anti-aliasing properties, create (or edit, if it already exists) the file /usr/X11R6/etc/fonts/local.conf. Several advanced features of the Xft font system can be tuned using this file; this section describes only some simple possibilities. For more details, please see fonts-conf(5).

This file must be in XML format. Pay careful attention to case, and make sure all tags are properly closed. The file begins with the usual XML header followed by a DOCTYPE definition, and then the <fontconfig> tag:

      <?xml version="1.0"?>
      <!DOCTYPE fontconfig SYSTEM "fonts.dtd">
      <fontconfig>
   

As previously stated, all fonts in /usr/X11R6/lib/X11/fonts/ as well as ~/.fonts/ are already made available to Xft-aware applications. If you wish to add another directory outside of these two directory trees, add a line similar to the following to /usr/X11R6/etc/fonts/local.conf:

<dir>/path/to/my/fonts</dir>

After adding new fonts, and especially new font directories, you should run the following command to rebuild the font caches:

# fc-cache -f

Anti-aliasing makes borders slightly fuzzy, which makes very small text more readable and removes ``staircases'' from large text, but can cause eyestrain if applied to normal text. To exclude point sizes smaller than 14 point from anti-aliasing, include these lines:

        <match target="font">
            <test name="size" compare="less">
                <double>14</double>
            </test>
            <edit name="antialias" mode="assign">
                <bool>false</bool>
            </edit>
        </match>

Spacing for some monospaced fonts may also be inappropriate with anti-aliasing. This seems to be an issue with KDE, in particular. One possible fix for this is to force the spacing for such fonts to be 100. Add the following lines:

       <match target="pattern" name="family">
           <test qual="any" name="family">
               <string>fixed</string>
           </test>
           <edit name="family" mode="assign">
               <string>mono</string>
           </edit>
        </match>
        <match target="pattern" name="family">
            <test qual="any" name="family">
                <string>console</string>
            </test>
            <edit name="family" mode="assign">
                <string>mono</string>
            </edit>
        </match>

(this aliases the other common names for fixed fonts as "mono"), and then add:

         <match target="pattern" name="family">
             <test qual="any" name="family">
                 <string>mono</string>
             </test>
             <edit name="spacing" mode="assign">
                 <int>100</int>
             </edit>
         </match>     

Certain fonts, such as Helvetica, may have a problem when anti-aliased. Usually this manifests itself as a font that seems cut in half vertically. At worst, it may cause applications such as Mozilla to crash. To avoid this, consider adding the following to local.conf:

         <match target="pattern" name="family">
             <test qual="any" name="family">
                 <string>Helvetica</string>
             </test>
             <edit name="family" mode="assign">
                 <string>sans-serif</string>
             </edit>
         </match>       

Once you have finished editing local.conf make sure you end the file with the </fontconfig> tag. Not doing this will cause your changes to be ignored.

The default font set that comes with XFree86 is not very desirable when it comes to anti-aliasing. A much better set of default fonts can be found in the x11-fonts/bitstream-vera port. This port will install a /usr/X11R6/etc/fonts/local.conf file if one does not exist already. If the file does exist, the port will create a /usr/X11R6/etc/fonts/local.conf-vera file. Merge the contents of this file into /usr/X11R6/etc/fonts/local.conf, and the Bitstream fonts will automatically replace the default XFree86 Serif, Sans Serif, and Monospaced fonts.

Finally, users can add their own settings via their personal .fonts.conf files. To do this, each user should simply create a ~/.fonts.conf. This file must also be in XML format.

One last point: with an LCD screen, sub-pixel sampling may be desired. This basically treats the (horizontally separated) red, green and blue components separately to improve the horizontal resolution; the results can be dramatic. To enable this, add the line somewhere in the local.conf file:

         <match target="font">
             <test qual="all" name="rgba">
                 <const>unknown</const>
             </test>
             <edit name="rgba" mode="assign">
                 <const>rgb</const>
             </edit>
         </match>
      

Note: Depending on the sort of display, rgb may need to be changed to bgr, vrgb or vbgr: experiment and see which works best.

Anti-aliasing should be enabled the next time the X server is started. However, programs must know how to take advantage of it. At present, the Qt toolkit does, so the entire KDE environment can use anti-aliased fonts (see Section 5.7.3.2 on KDE for details). Gtk+ and GNOME can also be made to use anti-aliasing via the ``Font'' capplet (see Section 5.7.1.3 for details). By default, Mozilla 1.2 and greater will automatically use anti-aliasing. To disable this, rebuild Mozilla with the -DWITHOUT_XFT flag.


5.6 The X Display Manager

Contributed by Seth Kingsley.

5.6.1 Overview

The X Display Manager (XDM) is an optional part of the X Window System that is used for login session management. This is useful for several types of situations, including minimal ``X Terminals'', desktops, and large network display servers. Since the X Window System is network and protocol independent, there are a wide variety of possible configurations for running X clients and servers on different machines connected by a network. XDM provides a graphical interface for choosing which display server to connect to, and entering authorization information such as a login and password combination.

Think of XDM as providing the same functionality to the user as the getty(8) utility (see Section 17.3.2 for details). That is, it performs system logins to the display being connected to and then runs a session manager on behalf of the user (usually an X window manager). XDM then waits for this program to exit, signaling that the user is done and should be logged out of the display. At this point, XDM can display the login and display chooser screens for the next user to login.


5.6.2 Using XDM

The XDM daemon program is located in /usr/X11R6/bin/xdm. This program can be run at any time as root and it will start managing the X display on the local machine. If XDM is to be run every time the machine boots up, a convenient way to do this is by adding an entry to /etc/ttys. For more information about the format and usage of this file, see Section 17.3.2.1. There is a line in the default /etc/ttys file for running the XDM daemon on a virtual terminal:

ttyv8   "/usr/X11R6/bin/xdm -nodaemon"  xterm   off secure

By default this entry is disabled; in order to enable it change field 5 from off to on and restart init(8) using the directions in Section 17.3.2.2. The first field, the name of the terminal this program will manage, is ttyv8. This means that XDM will start running on the 9th virtual terminal.


5.6.3 Configuring XDM

The XDM configuration directory is located in /usr/X11R6/lib/X11/xdm. In this directory there are several files used to change the behavior and appearance of XDM. Typically these files will be found:

File Description
Xaccess Client authorization ruleset.
Xresources Default X resource values.
Xservers List of remote and local displays to manage.
Xsession Default session script for logins.
Xsetup_* Script to launch applications before the login interface.
xdm-config Global configuration for all displays running on this machine.
xdm-errors Errors generated by the server program.
xdm-pid The process ID of the currently running XDM.

Also in this directory are a few scripts and programs used to set up the desktop when XDM is running. The purpose of each of these files will be briefly described. The exact syntax and usage of all of these files is described in xdm(1).

The default configuration is a simple rectangular login window with the hostname of the machine displayed at the top in a large font and ``Login:'' and ``Password:'' prompts below. This is a good starting point for changing the look and feel of XDM screens.


5.6.3.1 Xaccess

The protocol for connecting to XDM controlled displays is called the X Display Manager Connection Protocol (XDMCP). This file is a ruleset for controlling XDMCP connections from remote machines. By default, it allows any client to connect, but that does not matter unless the xdm-config is changed to listen for remote connections.


5.6.3.2 Xresources

This is an application-defaults file for the display chooser and the login screens. This is where the appearance of the login program can be modified. The format is identical to the app-defaults file described in the XFree86 documentation.


5.6.3.3 Xservers

This is a list of the remote displays the chooser should provide as choices.


5.6.3.4 Xsession

This is the default session script for XDM to run after a user has logged in. Normally each user will have a customized session script in ~/.xsession that overrides this script.


5.6.3.5 Xsetup_*

These will be run automatically before displaying the chooser or login interfaces. There is a script for each display being used, named Xsetup_ followed by the local display number (for instance Xsetup_0). Typically these scripts will run one or two programs in the background such as xconsole.


5.6.3.6 xdm-config

This contains settings in the form of app-defaults that are applicable to every display that this installation manages.


5.6.3.7 xdm-errors

This contains the output of the X servers that XDM is trying to run. If a display that XDM is trying to start hangs for some reason, this is a good place to look for error messages. These messages are also written to the user's ~/.xsession-errors file on a per-session basis.


5.6.4 Running a Network Display Server

In order for other clients to connect to the display server, edit the access control rules, and enable the connection listener. By default these are set to conservative values. To make XDM listen for connections, first comment out a line in the xdm-config file:

! SECURITY: do not listen for XDMCP or Chooser requests
! Comment out this line if you want to manage X terminals with xdm
DisplayManager.requestPort:     0

and then restart XDM. Remember that comments in app-defaults files begin with a ``!'' character, not the usual ``#''. More strict access controls may be desired. Look at the example entries in Xaccess, and refer to the xdm(1) manual page.


5.6.5 Replacements for XDM

Several replacements for the default XDM program exist. One of them, KDM (bundled with KDE) is described later in this chapter. KDM offers many visual improvements and cosmetic frills, as well as the functionality to allow users to choose their window manager of choice at login time.


5.7 Desktop Environments

Contributed by Valentino Vaschetto.

This section describes the different desktop environments available for X on FreeBSD. A ``desktop environment'' can mean anything ranging from a simple window manager to a complete suite of desktop applications, such as KDE or GNOME.


5.7.1 GNOME

5.7.1.1 About GNOME

GNOME is a user-friendly desktop environment that enables users to easily use and configure their computers. GNOME includes a panel (for starting applications and displaying status), a desktop (where data and applications can be placed), a set of standard desktop tools and applications, and a set of conventions that make it easy for applications to cooperate and be consistent with each other. Users of other operating systems or environments should feel right at home using the powerful graphics-driven environment that GNOME provides. More information regarding GNOME on FreeBSD can be found on the FreeBSD GNOME Project's web site.


5.7.1.2 Installing GNOME

The easiest way to install GNOME is through the ``Desktop Configuration'' menu during the FreeBSD installation process as described in Section 2.9.13 of Chapter 2. It can also be easily installed from a package or the ports collection:

To install the GNOME package from the network, simply type:

# pkg_add -r gnome2

To build GNOME from source, use the ports tree:

# cd /usr/ports/x11/gnome2
# make install clean

Once GNOME is installed, the X server must be told to start GNOME instead of a default window manager. If a custom .xinitrc is already in place, simply replace the line that starts the current window manager with one that starts /usr/X11R6/bin/gnome-session instead. If nothing special has been done to configuration file, then it is enough to simply type:

% echo "/usr/X11R6/bin/gnome-session" > ~/.xinitrc

Next, type startx, and the GNOME desktop environment will be started.

Note: If a display manager, like XDM, is being used, this will not work. Instead, create an executable .xsession file with the same command in it. To do this, edit the file and replace the existing window manager command with /usr/X11R6/bin/gnome-session:

% echo "#!/bin/sh" > ~/.xsession
% echo "/usr/X11R6/bin/gnome-session" >> ~/.xsession
% chmod +x ~/.xsession

Another option is to configure the display manager to allow choosing the window manager at login time; the section on KDE details explains how to do this for kdm, the display manager of KDE.


5.7.1.3 Anti-aliased Fonts with GNOME

Starting with version 4.0.2, XFree86 supports anti-aliasing via its ``RENDER'' extension. Gtk+ 2.0 and greater (the toolkit used by GNOME) can make use of this functionality. Configuring anti-aliasing is described in Section 5.5.3. So, with up-to-date software, anti-aliasing is possible within the GNOME desktop. Just go to Applications->Desktop Preferences->Font, and select either Best shapes, Best contrast, or Subpixel smoothing (LCDs). For a Gtk+ application that is not part of the GNOME desktop, set the environment variable GDK_USE_XFT to 1 before launching the program.


5.7.2 KDE


5.7.2.1 About KDE

KDE is an easy to use contemporary desktop environment. Some of the things that KDE brings to the user are:

  • A beautiful contemporary desktop

  • A desktop exhibiting complete network transparency

  • An integrated help system allowing for convenient, consistent access to help on the use of the KDE desktop and its applications

  • Consistent look and feel of all KDE applications

  • Standardized menu and toolbars, keybindings, color-schemes, etc.

  • Internationalization: KDE is available in more than 40 languages

  • Centralized consisted dialog driven desktop configuration

  • A great number of useful KDE applications

KDE has an office application suite based on KDE's ``KParts'' technology consisting of a spread-sheet, a presentation application, an organizer, a news client and more. KDE also comes with a web browser called Konqueror, which represents a solid competitor to other existing web browsers on UNIX systems. More information on KDE can be found on the KDE website. For FreeBSD specific informations and resources on KDE, consult the FreeBSD-KDE team's website.


5.7.2.2 Installing KDE

Just as with GNOME or any other desktop environment, the easiest way to install KDE is through the ``Desktop Configuration'' menu during the FreeBSD installation process as described in Section 2.9.13 of Chapter 2. Once again, the software can be easily installed from a package or from the ports collection:

To install the KDE package from the network, simply type:

# pkg_add -r kde

pkg_add(1) will automatically fetch the latest version of the application.

To build KDE from source, use the ports tree:

# cd /usr/ports/x11/kde3
# make install clean

After KDE has been installed, the X server must be told to launch this application instead of the default window manager. This is accomplished by editing the .xinitrc file:

% echo "exec startkde" > ~/.xinitrc

Now, whenever the X Window System is invoked with startx, KDE will be the desktop.

If a display manager such as xdm is being used, the configuration is slightly different. Edit the .xsession file instead. Instructions for kdm are described later in this chapter.


5.7.3 More Details on KDE

Now that KDE is installed on the system, most things can be discovered through the help pages, or just by pointing and clicking at various menus. Windows or Mac® users will feel quite at home.

The best reference for KDE is the on-line documentation. KDE comes with its own web browser, Konqueror, dozens of useful applications, and extensive documentation. The remainder of this section discusses the technical items that are difficult to learn by random exploration.


5.7.3.1 The KDE Display Manager

An administrator of a multi-user system may wish to have a graphical login screen to welcome users. xdm can be used, as described earlier. However, KDE includes an alternative, kdm, which is designed to look more attractive and include more login-time options. In particular, users can easily choose (via a menu) which desktop environment (KDE, GNOME, or something else) to run after logging on.

To begin with, run the KDE control panel, kcontrol, as root. It is generally considered unsafe to run the entire X environment as root. Instead, run the window manager as a normal user, open a terminal window (such as xterm or KDE's konsole), become root with su (the user must be in the wheel group in /etc/group for this), and then type kcontrol.

Click on the icon on the left marked System, then on Login manager. On the right there are various configurable options, which the KDE manual will explain in greater detail. Click on sessions on the right. Click New type to add various window managers and desktop environments. These are just labels, so they can say KDE and GNOME rather than startkde or gnome-session. Include a label failsafe.

Play with the other menus as well, they are mainly cosmetic and self-explanatory. When you are done, click on Apply at the bottom, and quit the control center.

To make sure kdm understands what the labels (KDE, GNOME etc) mean, edit the files used by xdm.

Note: In KDE 2.2 this has changed: kdm now uses its own configuration files. Please see the KDE 2.2 documentation for details.

In a terminal window, as root, edit the file /usr/X11R6/lib/X11/xdm/Xsession. There is a section in the middle like this:

case $# in
1)
        case $1 in
        failsafe)
                exec xterm -geometry 80x24-0-0
                ;;
        esac
esac

A few lines need to be added to this section. Assuming the labels from used were ``KDE'' and ``GNOME'', use the following:

case $# in
1)
        case $1 in
        kde)
                exec /usr/local/bin/startkde
                ;;
        GNOME)
                exec /usr/X11R6/bin/gnome-session
                ;;
        failsafe)
                exec xterm -geometry 80x24-0-0
                ;;
        esac
esac

For the KDE login-time desktop background to be honored, the following line needs to be added to /usr/X11R6/lib/X11/xdm/Xsetup_0:

/usr/local/bin/kdmdesktop

Now, make sure kdm is listed in /etc/ttys to be started at the next bootup. To do this, simply follow the instructions from the previous section on xdm and replace references to the /usr/X11R6/bin/xdm program with /usr/local/bin/kdm.


5.7.3.2 Anti-aliased Fonts

Starting with version 4.0.2, XFree86 supports anti-aliasing via its ``RENDER'' extension, and starting with version 2.3, Qt (the toolkit used by KDE) supports this extension. Configuring this is described in Section 5.5.3 on antialiasing X11 fonts. So, with up-to-date software, anti-aliasing is possible on a KDE desktop. Just go to the KDE menu, go to Preferences->Look and Feel->Fonts, and click on the check box Use Anti-Aliasing for Fonts and Icons. For a Qt application which is not part of KDE, the environment variable QT_XFT needs to be set to true before starting the program.


5.7.4 XFce

5.7.4.1 About XFce

XFce is a desktop environment based on the GTK toolkit used by GNOME, but is much more lightweight and meant for those who want a simple, efficient desktop which is nevertheless easy to use and configure. Visually, it looks very much like CDE, found on commercial UNIX systems. Some of XFce's features are:

  • A simple, easy-to-handle desktop

  • Fully configurable via mouse, with drag and drop, etc

  • Main panel similar to CDE, with menus, applets and applications launchers

  • Integrated window manager, file manager, sound manager, GNOME compliance module, and other things

  • Themeable (since it uses GTK)

  • Fast, light and efficient: ideal for older/slower machines or machines with memory limitations

More information on XFce can be found on the XFce website.


5.7.4.2 Installing XFce

A binary package for XFce exists (at the time of writing). To install, simply type:

# pkg_add -r xfce4

Alternatively, to build from source, use the ports collection:

# cd /usr/ports/x11-wm/xfce4
# make install clean

Now, tell the X server to launch XFce the next time X is started. Simply type this:

% echo "/usr/X11R6/bin/startxfce" > ~/.xinitrc

The next time X is started, XFce will be the desktop. As before, if a display manager like xdm is being used, create an .xsession, as described in the section on GNOME, but with the /usr/X11R6/bin/startxfce command; or, configure the display manager to allow choosing a desktop at login time, as explained in the section on kdm.

II. System Administration

The remaining chapters of the FreeBSD Handbook cover all aspects of FreeBSD system administration. Each chapter starts by describing what you will learn as a result of reading the chapter, and also details what you are expected to know before tackling the material.

These chapters are designed to be read when you need the information. You do not have to read them in any particular order, nor do you need to read all of them before you can begin using FreeBSD.


Chapter 6 Configuration and Tuning

Written by Chern Lee. Based on a tutorial written by Mike Smith. Also based on tuning(7) written by Matt Dillon.

6.1 Synopsis

One of the important aspects of FreeBSD is system configuration. Correct system configuration will help prevent headaches during future upgrades. This chapter will explain much of the FreeBSD configuration process, including some of the parameters which can be set to tune a FreeBSD system.

After reading this chapter, you will know:

  • How to efficiently work with file systems and swap partitions.

  • The basics of rc.conf configuration and /usr/local/etc/rc.d startup systems.

  • How to configure and test a network card.

  • How to configure virtual hosts on your network devices.

  • How to use the various configuration files in /etc.

  • How to tune FreeBSD using sysctl variables.

  • How to tune disk performance and modify kernel limitations.

Before reading this chapter, you should:

  • Understand UNIX and FreeBSD basics (Chapter 3).

  • Be familiar with keeping FreeBSD sources up to date (Chapter 21), and the basics of kernel configuration/compilation (Chapter 9).


6.2 Initial Configuration

6.2.1 Partition Layout


6.2.1.1 Base Partitions

When laying out file systems with disklabel(8) or sysinstall(8), remember that hard drives transfer data faster from the outer tracks to the inner. Thus smaller and heavier-accessed file systems should be closer to the outside of the drive, while larger partitions like /usr should be placed toward the inner. It is a good idea to create partitions in a similar order to: root, swap, /var, /usr.

The size of /var reflects the intended machine usage. /var is used to hold mailboxes, log files, and printer spools. Mailboxes and log files can grow to unexpected sizes depending on how many users exist and how long log files are kept. Most users would never require a gigabyte, but remember that /var/tmp must be large enough to contain packages.

The /usr partition holds much of the files required to support the system, the ports(7) collection (recommended) and the source code (optional). Both of which are optional at install time. At least 2 gigabytes would be recommended for this partition.

When selecting partition sizes, keep the space requirements in mind. Running out of space in one partition while barely using another can be a hassle.

Note: Some users have found that sysinstall(8)'s Auto-defaults partition sizer will sometimes select smaller than adequate /var and / partitions. Partition wisely and generously.


6.2.1.2 Swap Partition

As a rule of thumb, the swap partition should be about double the size of system memory (RAM). For example, if the machine has 128 megabytes of memory, the swap file should be 256 megabytes. Systems with less memory may perform better with more swap. Less than 256 megabytes of swap is not recommended and memory expansion should be considered. The kernel's VM paging algorithms are tuned to perform best when the swap partition is at least two times the size of main memory. Configuring too little swap can lead to inefficiencies in the VM page scanning code and might create issues later if more memory is added.

On larger systems with multiple SCSI disks (or multiple IDE disks operating on different controllers), it is recommend that a swap is configured on each drive (up to four drives). The swap partitions should be approximately the same size. The kernel can handle arbitrary sizes but internal data structures scale to 4 times the largest swap partition. Keeping the swap partitions near the same size will allow the kernel to optimally stripe swap space across disks. Large swap sizes are fine, even if swap is not used much. It might be easier to recover from a runaway program before being forced to reboot.


6.2.1.3 Why Partition?

Several users think a single large partition will be fine, but there are several reasons why this is a bad idea. First, each partition has different operational characteristics and separating them allows the file system to tune accordingly. For example, the root and /usr partitions are read-mostly, without much writing. While a lot of reading and writing could occur in /var and /var/tmp.

By properly partitioning a system, fragmentation introduced in the smaller write heavy partitions will not bleed over into the mostly-read partitions. Keeping the write-loaded partitions closer to the disk's edge, will increase I/O performance in the partitions where it occurs the most. Now while I/O performance in the larger partitions may be needed, shifting them more toward the edge of the disk will not lead to a significant performance improvement over moving /var to the edge. Finally, there are safety concerns. A smaller, neater root partition which is mostly read-only has a greater chance of surviving a bad crash.


6.3 Core Configuration

The principal location for system configuration information is within /etc/rc.conf. This file contains a wide range of configuration information, principally used at system startup to configure the system. Its name directly implies this; it is configuration information for the rc* files.

An administrator should make entries in the rc.conf file to override the default settings from /etc/defaults/rc.conf. The defaults file should not be copied verbatim to /etc - it contains default values, not examples. All system-specific changes should be made in the rc.conf file itself.

A number of strategies may be applied in clustered applications to separate site-wide configuration from system-specific configuration in order to keep administration overhead down. The recommended approach is to place site-wide configuration into another file, such as /etc/rc.conf.site, and then include this file into /etc/rc.conf, which will contain only system-specific information.

As rc.conf is read by sh(1) it is trivial to achieve this. For example:

  • rc.conf:

       . rc.conf.site
        hostname="node15.example.com"
        network_interfaces="fxp0 lo0"
        ifconfig_fxp0="inet 10.1.1.1"
    
  • rc.conf.site:

       defaultrouter="10.1.1.254"
        saver="daemon"
        blanktime="100"
    

The rc.conf.site file can then be distributed to every system using rsync or a similar program, while the rc.conf file remains unique.

Upgrading the system using sysinstall(8) or make world will not overwrite the rc.conf file, so system configuration information will not be lost.


6.4 Application Configuration

Typically, installed applications have their own configuration files, with their own syntax, etc. It is important that these files be kept separate from the base system, so that they may be easily located and managed by the package management tools.

Typically, these files are installed in /usr/local/etc. In the case where an application has a large number of configuration files, a subdirectory will be created to hold them.

Normally, when a port or package is installed, sample configuration files are also installed. These are usually identified with a .default suffix. If there are no existing configuration files for the application, they will be created by copying the .default files.

For example, consider the contents of the directory /usr/local/etc/apache:

-rw-r--r--  1 root  wheel   2184 May 20  1998 access.conf
-rw-r--r--  1 root  wheel   2184 May 20  1998 access.conf.default
-rw-r--r--  1 root  wheel   9555 May 20  1998 httpd.conf
-rw-r--r--  1 root  wheel   9555 May 20  1998 httpd.conf.default
-rw-r--r--  1 root  wheel  12205 May 20  1998 magic
-rw-r--r--  1 root  wheel  12205 May 20  1998 magic.default
-rw-r--r--  1 root  wheel   2700 May 20  1998 mime.types
-rw-r--r--  1 root  wheel   2700 May 20  1998 mime.types.default
-rw-r--r--  1 root  wheel   7980 May 20  1998 srm.conf
-rw-r--r--  1 root  wheel   7933 May 20  1998 srm.conf.default

The file sizes show that only the srm.conf file has been changed. A later update of the Apache port would not overwrite this changed file.


6.5 Starting Services

It is common for a system to host a number of services. These may be started in several different fashions, each having different advantages.

Software installed from a port or the packages collection will often place a script in /usr/local/etc/rc.d which is invoked at system startup with a start argument, and at system shutdown with a stop argument. This is the recommended way for starting system-wide services that are to be run as root, or that expect to be started as root. These scripts are registered as part of the installation of the package, and will be removed when the package is removed.

A generic startup script in /usr/local/etc/rc.d looks like:

#!/bin/sh
echo -n ' FooBar'

case "$1" in
start)
        /usr/local/bin/foobar
        ;;
stop)
        kill -9 `cat /var/run/foobar.pid`
        ;;
*)
        echo "Usage: `basename $0` {start|stop}" >&2
        exit 64
        ;;
esac

exit 0
   

The startup scripts of FreeBSD will look in /usr/local/etc/rc.d for scripts that have an .sh extension and are executable by root. Those scripts that are found are called with an option start at startup, and stop at shutdown to allow them to carry out their purpose. So if you wanted the above sample script to be picked up and run at the proper time during system startup, you should save it to a file called FooBar.sh in /usr/local/etc/rc.d and make sure it is executable. You can make a shell script executable with chmod(1) as shown below:

# chmod 755 FooBar.sh

Some services expect to be invoked by inetd(8) when a connection is received on a suitable port. This is common for mail reader servers (POP and IMAP, etc.). These services are enabled by editing the file /etc/inetd.conf. See inetd(8) for details on editing this file.

Some additional system services may not be covered by the toggles in /etc/rc.conf. These are traditionally enabled by placing the command(s) to invoke them in /etc/rc.local. As of FreeBSD 3.1 there is no default /etc/rc.local; if it is created by the administrator it will however be honored in the normal fashion. Note that rc.local is generally regarded as the location of last resort; if there is a better place to start a service, do it there.

Note: Do not place any commands in /etc/rc.conf. To start daemons, or run any commands at boot time, place a script in /usr/local/etc/rc.d instead.

It is also possible to use the cron(8) daemon to start system services. This approach has a number of advantages, not least being that because cron(8) runs these processes as the owner of the crontab, services may be started and maintained by non-root users.

This takes advantage of a feature of cron(8): the time specification may be replaced by @reboot, which will cause the job to be run when cron(8) is started shortly after system boot.


6.6 Configuring the cron Utility

Contributed by Tom Rhodes.

One of the most useful utilities in FreeBSD is cron(8). The cron utility runs in the background and constantly checks the /etc/crontab file. The cron utility also checks the /var/cron/tabs directory, in search of new crontab files. These crontab files store information about specific functions which cron is supposed to perform at certain times.

Let us take a look at the /etc/crontab file:

# /etc/crontab - root's crontab for FreeBSD
#
# $FreeBSD: src/etc/crontab,v 1.32 2002/11/22 16:13:39 tom Exp $
# (1)
#
SHELL=/bin/sh
PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin (2)
HOME=/var/log
#
#
#minute hour    mday    month   wday    who command (3)
#
#
*/5 *   *   *   *   root    /usr/libexec/atrun (4)
(1)
Like most FreeBSD configuration files, the # character represents a comment. A comment can be placed in the file as a reminder of what and why a desired action is performed. Comments cannot be on the same line as a command or else they will be interpreted as part of the command; they must be on a new line. Blank lines are ignored.
(2)
First, the environment must be defined. The equals (=) character is used to define any environment settings, as with this example where it is used for the SHELL, PATH, and HOME options. If the shell line is omitted, cron will use the default, which is sh. If the PATH variable is omitted, no default will be used and file locations will need to be absolute. If HOME is omitted, cron will use the invoking users home directory.
(3)
This line defines a total of seven fields. Listed here are the values minute, hour, mday, month, wday, who, and command. These are almost all self explanatory. minute is the time in minutes the command will be run. hour is similar to the minute option, just in hours. mday stands for day of the month. month is similar to hour and minute, as it designates the month. The wday option stands for day of the week. All these fields must be numeric values, and follow the twenty-four hour clock. The who field is special, and only exists in the /etc/crontab file. This field specifies which user the command should be run as. When a user installs his or her crontab file, they will not have this option. Finally, the command option is listed. This is the last field, so naturally it should designate the command to be executed.
(4)
This last line will define the values discussed above. Notice here we have a */5 listing, followed by several more * characters. These * characters mean ``first-last'', and can be interpreted as every time. So, judging by this line, it is apparent that the atrun command is to be invoked by root every five minutes regardless of what day or month it is. For more information on the atrun command, see the atrun(8) manual page.

Commands can have any number of flags passed to them; however, commands which extend to multiple lines need to be broken with the backslash ``\'' continuation character.

This is the basic set up for every crontab file, although there is one thing different about this one. Field number six, where we specified the username, only exists in the system /etc/crontab file. This field should be omitted for individual user crontab files.


6.6.1 Installing a Crontab

To install your freshly written crontab, just use the crontab utility. The most common usage is:

# crontab crontab

There is also an option to list installed crontab files, just pass the -l to crontab and look over the output.

For users who wish to begin their own crontab file from scratch, without the use of a template, the crontab -e option is available. This will invoke the selected editor with an empty file. When the file is saved, it will be automatically installed by the crontab command.


6.7 Using rc under FreeBSD 5.X

Contributed by Tom Rhodes.

FreeBSD has recently integrated the NetBSD rc.d system for system initialization. Users should notice the files listed in the /etc/rc.d directory. Many of these files are for basic services which can be controlled with the start, stop, and restart options. For instance, sshd(8) can be restarted with the following command:

# /etc/rc.d/sshd restart

This procedure is similar for other services. Of course, services are usually started automatically as specified in rc.conf(5). For example, enabling the Network Address Translation daemon at startup is as simple as adding the following line to /etc/rc.conf:

natd_enable="YES"

If a natd_enable="NO" line is already present, then simply change the NO to YES. The rc scripts will automatically load any other dependent services during the next reboot, as described below.

Since the rc.d system is primarily intended to start/stop services at system startup/shutdown time; the standard start, stop and restart options will only perform their action if the appropriate /etc/rc.conf variables are set. For instance the above sshd restart command will only work if sshd_enable is set to YES in /etc/rc.conf. To start, stop or restart a service regardless of the settings in /etc/rc.conf, the commands should be prefixed with ``force''. For instance to restart sshd regardless of the current /etc/rc.conf setting, execute the following command:

# /etc/rc.d/sshd forcerestart

It is easy to check if a service is enabled in /etc/rc.conf by running the appropriate rc.d script with the option rcvar. Thus, an administrator can check that sshd is in fact enabled in /etc/rc.conf by running:

# /etc/rc.d/sshd rcvar
# sshd
$sshd_enable=YES

Note: The second line (# sshd) is the output from the sshd command, not a root console.

To determine if a service is running, a status option is available. For instance to verify that sshd is actually started:

# /etc/rc.d/sshd status
sshd is running as pid 433.

It is also possible to reload a service. This will attempt to send a signal to an individual service, forcing the service to reload its configuration files. In most cases this means sending the service a SIGHUP signal.

The rcNG structure is not only used for network services, it also contributes to most of the system initialization. For instance, consider the bgfsck file. When this script is executed, it will print out the following message:

Starting background file system checks in 60 seconds.

Therefore this file is used for background file system checks, which are done only during system initialization.

Many system services depend on other services to function properly. For example, NIS and other RPC-based services may fail to start until after the rpcbind (portmapper) service has started. To resolve this issue, information about dependencies and other meta-data is included in the comments at the top of each startup script. The rcorder(8) program is then used to parse these comments during system initialization to determine the order in which system services should be invoked to satisfy the dependencies. The following words may be included at the top of each startup file:

  • PROVIDE: Specifies the services this file provides.

  • REQUIRE: Lists services which are required for this service. This file will run after the specified services.

  • BEFORE: Lists services which depend on this service. This file will run before the specified services.

  • KEYWORD: FreeBSD or NetBSD. This is used for *BSD dependent features.

By using this method, an administrator can easily control system services without the hassle of ``runlevels'' like some other UNIX operating systems.

Additional information about the FreeBSD 5.X rc.d system can be found in the rc(8) and rc.subr(8) manual pages.


6.8 Setting Up Network Interface Cards

Contributed by Marc Fonvieille.

Nowadays we can not think about a computer without thinking about a network connection. Adding and configuring a network card is a common task for any FreeBSD administrator.


6.8.1 Locating the Correct Driver

Before you begin, you should know the model of the card you have, the chip it uses, and whether it is a PCI or ISA card. FreeBSD supports a wide variety of both PCI and ISA cards. Check the Hardware Compatibility List for your release to see if your card is supported.

Once you are sure your card is supported, you need to determine the proper driver for the card. The file /usr/src/sys/i386/conf/LINT will give you the list of network interfaces drivers with some information about the supported chipsets/cards. If you have doubts about which driver is the correct one, read the manual page of the driver. The manual page will give you more information about the supported hardware and even the possible problems that could occur.

If you own a common card, most of the time you will not have to look very hard for a driver. Drivers for common network cards are present in the GENERIC kernel, so your card should show up during boot, like so:

dc0: <82c169 PNIC 10/100BaseTX> port 0xa000-0xa0ff mem 0xd3800000-0xd38
000ff irq 15 at device 11.0 on pci0
dc0: Ethernet address: 00:a0:cc:da:da:da
miibus0: <MII bus> on dc0
ukphy0: <Generic IEEE 802.3u media interface> on miibus0
ukphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
dc1: <82c169 PNIC 10/100BaseTX> port 0x9800-0x98ff mem 0xd3000000-0xd30
000ff irq 11 at device 12.0 on pci0
dc1: Ethernet address: 00:a0:cc:da:da:db
miibus1: <MII bus> on dc1
ukphy1: <Generic IEEE 802.3u media interface> on miibus1
ukphy1:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto

In this example, we see that two cards using the dc(4) driver are present on the system.

To use your network card, you will need to load the proper driver. This may be accomplished in one of two ways. The easiest way is to simply load a kernel module for your network card with kldload(8). A module is not available for all network card drivers (ISA cards and cards using the ed(4) driver, for example). Alternatively, you may statically compile the support for your card into your kernel. Check /usr/src/sys/i386/conf/LINT and the manual page of the driver to know what to add in your kernel configuration file. For more information about recompiling your kernel, please see Chapter 9. If your card was detected at boot by your kernel (GENERIC) you do not have to build a new kernel.


6.8.2 Configuring the Network Card

Once the right driver is loaded for the network card, the card needs to be configured. As with many other things, the network card may have been configured at installation time by sysinstall.

To display the configuration for the network interfaces on your system, enter the following command:

% ifconfig
dc0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 192.168.1.3 netmask 0xffffff00 broadcast 192.168.1.255
        ether 00:a0:cc:da:da:da
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active
dc1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet 10.0.0.1 netmask 0xffffff00 broadcast 10.0.0.255
        ether 00:a0:cc:da:da:db
        media: Ethernet 10baseT/UTP
        status: no carrier
lp0: flags=8810<POINTOPOINT,SIMPLEX,MULTICAST> mtu 1500
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
        inet 127.0.0.1 netmask 0xff000000
tun0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500

Note: Old versions of FreeBSD may require the -a option following ifconfig(8), for more details about the correct syntax of ifconfig(8), please refer to the manual page. Note also that entries concerning IPv6 (inet6 etc.) were omitted in this example.

In this example, the following devices were displayed:

  • dc0: The first Ethernet interface

  • dc1: The second Ethernet interface

  • lp0: The parallel port interface

  • lo0: The loopback device

  • tun0: The tunnel device used by ppp

FreeBSD uses the driver name followed by the order in which one the card is detected at the kernel boot to name the network card. For example sis2 would be the third network card on the system using the sis(4) driver.

In this example, the dc0 device is up and running. The key indicators are:

  1. UP means that the card is configured and ready.

  2. The card has an Internet (inet) address (in this case 192.168.1.3).

  3. It has a valid subnet mask (netmask; 0xffffff00 is the same as 255.255.255.0).

  4. It has a valid broadcast address (in this case, 192.168.1.255).

  5. The MAC address of the card (ether) is 00:a0:cc:da:da:da

  6. The physical media selection is on autoselection mode (media: Ethernet autoselect (100baseTX <full-duplex>)). We see that dc1 was configured to run with 10baseT/UTP media. For more information on available media types for a driver, please refer to its manual page.

  7. The status of the link (status) is active, i.e. the carrier is detected. For dc1, we see status: no carrier. This is normal when an ethernet cable is not plugged into the card.

If the ifconfig(8) output had shown something similar to:

dc0: flags=8843<BROADCAST,SIMPLEX,MULTICAST> mtu 1500
            ether 00:a0:cc:da:da:da

it would indicate the card has not been configured.

To configure your card, you need root privileges. The network card configuration can be done from the command line with ifconfig(8) but you would have to do it after each reboot of the system. The file /etc/rc.conf is where to add the network card's configuration.

Open /etc/rc.conf in your favorite editor. You need to add a line for each network card present on the system, for example in our case, we added these lines:

ifconfig_dc0="inet 192.168.1.3 netmask 255.255.255.0"
ifconfig_dc1="inet 10.0.0.1 netmask 255.255.255.0 media 10baseT/UTP"

You have to replace dc0, dc1, and so on, with the correct device for your cards, and the addresses with the proper ones. You should read the card driver and ifconfig(8) manual pages for more details about the allowed options and also rc.conf(5) manual page for more information on the syntax of /etc/rc.conf.

If you configured the network during installation, some lines about the network card(s) may be already present. Double check /etc/rc.conf before adding any lines.

You will also have to edit the file /etc/hosts to add the names and the IP addresses of various machines of the LAN, if they are not already there. For more information please refer to hosts(5) and to /usr/share/examples/etc/hosts.


6.8.3 Testing and Troubleshooting

Once you have made the necessary changes in /etc/rc.conf, you should reboot your system. This will allow the change(s) to the interface(s) to be applied, and verify that the system restarts without any configuration errors.

Once the system has been rebooted, you should test the network interfaces.


6.8.3.1 Testing the Ethernet Card

To verify that an Ethernet card is configured correctly, you have to try two things. First, ping the interface itself, and then ping another machine on the LAN.

First test the local interface:

% ping -c5 192.168.1.3
PING 192.168.1.3 (192.168.1.3): 56 data bytes
64 bytes from 192.168.1.3: icmp_seq=0 ttl=64 time=0.082 ms
64 bytes from 192.168.1.3: icmp_seq=1 ttl=64 time=0.074 ms
64 bytes from 192.168.1.3: icmp_seq=2 ttl=64 time=0.076 ms
64 bytes from 192.168.1.3: icmp_seq=3 ttl=64 time=0.108 ms
64 bytes from 192.168.1.3: icmp_seq=4 ttl=64 time=0.076 ms

--- 192.168.1.3 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.074/0.083/0.108/0.013 ms

Now we have to ping another machine on the LAN:

% ping -c5 192.168.1.2
PING 192.168.1.2 (192.168.1.2): 56 data bytes
64 bytes from 192.168.1.2: icmp_seq=0 ttl=64 time=0.726 ms
64 bytes from 192.168.1.2: icmp_seq=1 ttl=64 time=0.766 ms
64 bytes from 192.168.1.2: icmp_seq=2 ttl=64 time=0.700 ms
64 bytes from 192.168.1.2: icmp_seq=3 ttl=64 time=0.747 ms
64 bytes from 192.168.1.2: icmp_seq=4 ttl=64 time=0.704 ms

--- 192.168.1.2 ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max/stddev = 0.700/0.729/0.766/0.025 ms

You could also use the machine name instead of 192.168.1.2 if you have set up the /etc/hosts file.


6.8.3.2 Troubleshooting

Troubleshooting hardware and software configurations is always a pain, and a pain which can be alleviated by checking the simple things first. Is your network cable plugged in? Have you properly configured the network services? Did you configure the firewall correctly? Is the card you are using supported by FreeBSD? Always check the hardware notes before sending off a bug report. Update your version of FreeBSD to the latest STABLE version. Check the mailing list archives, or perhaps search the Internet.

If the card works, yet performance is poor, it would be worthwhile to read over the tuning(7) manual page. You can also check the network configuration as incorrect network settings can cause slow connections.

Some users experience one or two ``device timeouts'', which is normal for some cards. If they continue, or are bothersome, you may wish to be sure the device is not conflicting with another device. Double check the cable connections. Perhaps you may just need to get another card.

At times, users see a few ``watchdog timeout'' errors. The first thing to do here is to check your network cable. Many cards require a PCI slot which supports Bus Mastering. On some old motherboards, only one PCI slot allows it (usually slot 0). Check the network card and the motherboard documentation to determine if that may be the problem.

``No route to host'' messages occur if the system is unable to route a packet to the destination host. This can happen if no default route is specified, or if a cable is unplugged. Check the output of netstat -rn and make sure there is a valid route to the host you are trying to reach. If there is not, read on to Chapter 19.

``ping: sendto: Permission denied'' error messages are often caused by a misconfigured firewall. If ipfw is enabled in the kernel but no rules have been defined, then the default policy is to deny all traffic, even ping requests! Read on to Section 10.8 for more information.

Sometimes performance of the card is poor, or below average. In these cases it is best to set the media selection mode from autoselect to the correct media selection. While this usually works for most hardware, it may not resolve this issue for everyone. Again, check all the network settings, and read over the tuning(7) manual page.


6.9 Virtual Hosts

A very common use of FreeBSD is virtual site hosting, where one server appears to the network as many servers. This is achieved by assigning multiple network addresses to a single interface.

A given network interface has one ``real'' address, and may have any number of ``alias'' addresses. These aliases are normally added by placing alias entries in /etc/rc.conf.

An alias entry for the interface fxp0 looks like:

ifconfig_fxp0_alias0="inet xxx.xxx.xxx.xxx netmask xxx.xxx.xxx.xxx"

Note that alias entries must start with alias0 and proceed upwards in order, (for example, _alias1, _alias2, and so on). The configuration process will stop at the first missing number.

The calculation of alias netmasks is important, but fortunately quite simple. For a given interface, there must be one address which correctly represents the network's netmask. Any other addresses which fall within this network must have a netmask of all 1s.

For example, consider the case where the fxp0 interface is connected to two networks, the 10.1.1.0 network with a netmask of 255.255.255.0 and the 202.0.75.16 network with a netmask of 255.255.255.240. We want the system to appear at 10.1.1.1 through 10.1.1.5 and at 202.0.75.17 through 202.0.75.20.

The following entries configure the adapter correctly for this arrangement:

 ifconfig_fxp0="inet 10.1.1.1 netmask 255.255.255.0"
 ifconfig_fxp0_alias0="inet 10.1.1.2 netmask 255.255.255.255"
 ifconfig_fxp0_alias1="inet 10.1.1.3 netmask 255.255.255.255"
 ifconfig_fxp0_alias2="inet 10.1.1.4 netmask 255.255.255.255"
 ifconfig_fxp0_alias3="inet 10.1.1.5 netmask 255.255.255.255"
 ifconfig_fxp0_alias4="inet 202.0.75.17 netmask 255.255.255.240"
 ifconfig_fxp0_alias5="inet 202.0.75.18 netmask 255.255.255.255"
 ifconfig_fxp0_alias6="inet 202.0.75.19 netmask 255.255.255.255"
 ifconfig_fxp0_alias7="inet 202.0.75.20 netmask 255.255.255.255"

6.10 Configuration Files

6.10.1 /etc Layout

There are a number of directories in which configuration information is kept. These include:

/etc Generic system configuration information; data here is system-specific.
/etc/defaults Default versions of system configuration files.
/etc/mail Extra sendmail(8) configuration, other MTA configuration files.
/etc/ppp Configuration for both user- and kernel-ppp programs.
/etc/namedb Default location for named(8) data. Normally named.conf and zone files are stored here.
/usr/local/etc Configuration files for installed applications. May contain per-application subdirectories.
/usr/local/etc/rc.d Start/stop scripts for installed applications.
/var/db Automatically generated system-specific database files, such as the package database, the locate database, and so on

6.10.2 Hostnames


6.10.2.1 /etc/resolv.conf

/etc/resolv.conf dictates how FreeBSD's resolver accesses the Internet Domain Name System (DNS).

The most common entries to resolv.conf are:

nameserver The IP address of a name server the resolver should query. The servers are queried in the order listed with a maximum of three.
search Search list for hostname lookup. This is normally determined by the domain of the local hostname.
domain The local domain name.

A typical resolv.conf:

search example.com
nameserver 147.11.1.11
nameserver 147.11.100.30

Note: Only one of the search and domain options should be used.

If you are using DHCP, dhclient(8) usually rewrites resolv.conf with information received from the DHCP server.


6.10.2.2 /etc/hosts

/etc/hosts is a simple text database reminiscent of the old Internet. It works in conjunction with DNS and NIS providing name to IP address mappings. Local computers connected via a LAN can be placed in here for simplistic naming purposes instead of setting up a named(8) server. Additionally, /etc/hosts can be used to provide a local record of Internet names, reducing the need to query externally for commonly accessed names.

# $FreeBSD$
#
# Host Database
# This file should contain the addresses and aliases
# for local hosts that share this file.
# In the presence of the domain name service or NIS, this file may
# not be consulted at all; see /etc/nsswitch.conf for the resolution order.
#
#
::1                     localhost localhost.my.domain myname.my.domain
127.0.0.1               localhost localhost.my.domain myname.my.domain

#
# Imaginary network.
#10.0.0.2               myname.my.domain myname
#10.0.0.3               myfriend.my.domain myfriend
#
# According to RFC 1918, you can use the following IP networks for
# private nets which will never be connected to the Internet:
#
#       10.0.0.0        -   10.255.255.255
#       172.16.0.0      -   172.31.255.255
#       192.168.0.0     -   192.168.255.255
#
# In case you want to be able to connect to the Internet, you need
# real official assigned numbers.  PLEASE PLEASE PLEASE do not try
# to invent your own network numbers but instead get one from your
# network provider (if any) or from the Internet Registry (ftp to
# rs.internic.net, directory `/templates').
#

/etc/hosts takes on the simple format of:

[Internet address] [official hostname] [alias1] [alias2] ...

For example:

10.0.0.1 myRealHostname.example.com myRealHostname foobar1 foobar2

Consult hosts(5) for more information.


6.10.3 Log File Configuration


6.10.3.1 syslog.conf

syslog.conf is the configuration file for the syslogd(8) program. It indicates which types of syslog messages are logged to particular log files.

# $FreeBSD$
#
#       Spaces ARE valid field separators in this file. However,
#       other *nix-like systems still insist on using tabs as field
#       separators. If you are sharing this file between systems, you
#       may want to use only tabs as field separators here.
#       Consult the syslog.conf(5) manual page.
*.err;kern.debug;auth.notice;mail.crit          /dev/console
*.notice;kern.debug;lpr.info;mail.crit;news.err /var/log/messages
security.*                                      /var/log/security
mail.info                                       /var/log/maillog
lpr.info                                        /var/log/lpd-errs
cron.*                                          /var/log/cron
*.err                                           root
*.notice;news.err                               root
*.alert                                         root
*.emerg                                         *
# uncomment this to log all writes to /dev/console to /var/log/console.log
#console.info                                   /var/log/console.log
# uncomment this to enable logging of all log messages to /var/log/all.log
#*.*                                            /var/log/all.log
# uncomment this to enable logging to a remote log host named loghost
#*.*                                            @loghost
# uncomment these if you're running inn
# news.crit                                     /var/log/news/news.crit
# news.err                                      /var/log/news/news.err
# news.notice                                   /var/log/news/news.notice
!startslip
*.*                                             /var/log/slip.log
!ppp
*.*                                             /var/log/ppp.log

Consult the syslog.conf(5) manual page for more information.


6.10.3.2 newsyslog.conf

newsyslog.conf is the configuration file for newsyslog(8), a program that is normally scheduled to run by cron(8). newsyslog(8) determines when log files require archiving or rearranging. logfile is moved to logfile.0, logfile.0 is moved to logfile.1, and so on. Alternatively, the log files may be archived in gzip(1) format causing them to be named: logfile.0.gz, logfile.1.gz, and so on.

newsyslog.conf indicates which log files are to be managed, how many are to be kept, and when they are to be touched. Log files can be rearranged and/or archived when they have either reached a certain size, or at a certain periodic time/date.

# configuration file for newsyslog
# $FreeBSD$
#
# filename          [owner:group]    mode count size when [ZB] [/pid_file] [sig_num]
/var/log/cron                           600  3     100  *     Z
/var/log/amd.log                        644  7     100  *     Z
/var/log/kerberos.log                   644  7     100  *     Z
/var/log/lpd-errs                       644  7     100  *     Z
/var/log/maillog                        644  7     *    @T00  Z
/var/log/sendmail.st                    644  10    *    168   B
/var/log/messages                       644  5     100  *     Z
/var/log/all.log                        600  7     *    @T00  Z
/var/log/slip.log                       600  3     100  *     Z
/var/log/ppp.log                        600  3     100  *     Z
/var/log/security                       600  10    100  *     Z
/var/log/wtmp                           644  3     *    @01T05 B
/var/log/daily.log                      640  7     *    @T00  Z
/var/log/weekly.log                     640  5     1    $W6D0 Z
/var/log/monthly.log                    640  12    *    $M1D0 Z
/var/log/console.log                    640  5     100  *     Z

Consult the newsyslog(8) manual page for more information.


6.10.4 sysctl.conf

sysctl.conf looks much like rc.conf. Values are set in a variable=value form. The specified values are set after the system goes into multi-user mode. Not all variables are settable in this mode.

A sample sysctl.conf turning off logging of fatal signal exits and letting Linux programs know they are really running under FreeBSD:

kern.logsigexit=0       # Do not log fatal signal exits (e.g. sig 11)
compat.linux.osname=FreeBSD
compat.linux.osrelease=4.3-STABLE

6.11 Tuning with sysctl

sysctl(8) is an interface that allows you to make changes to a running FreeBSD system. This includes many advanced options of the TCP/IP stack and virtual memory system that can dramatically improve performance for an experienced system administrator. Over five hundred system variables can be read and set using sysctl(8).

At its core, sysctl(8) serves two functions: to read and to modify system settings.

To view all readable variables:

% sysctl -a

To read a particular variable, for example, kern.maxproc:

% sysctl kern.maxproc
kern.maxproc: 1044

To set a particular variable, use the intuitive variable=value syntax:

# sysctl kern.maxfiles=5000
kern.maxfiles: 2088 -> 5000

Settings of sysctl variables are usually either strings, numbers, or booleans (a boolean being 1 for yes or a 0 for no).


6.11.1 sysctl(8) Read-only

Contributed by Tom Rhodes.

In some cases it may be desirable to modify read-only sysctl(8) values. While this is not recommended, it is also sometimes unavoidable.

For instance on some laptop models the cardbus(4) device will not probe memory ranges, and fail with errors which look similar to:

cbb0: Could not map register memory
device_probe_and_attach: cbb0 attach returned 12

Cases like the one above usually require the modification of some default sysctl(8) settings which are set read only. To overcome these situations a user can put sysctl(8) ``OIDs'' in their local /boot/loader.conf.local. Default settings are located in the /boot/defaults/loader.conf file.

Fixing the problem mentioned above would require a user to set hw.pci.allow_unsupported_io_range=1 in the aforementioned file. Now cardbus(4) will work properly.


6.12 Tuning Disks

6.12.1 Sysctl Variables

6.12.1.1 vfs.vmiodirenable

The vfs.vmiodirenable sysctl variable may be set to either 0 (off) or 1 (on); it is 1 by default. This variable controls how directories are cached by the system. Most directories are small, using just a single fragment (typically 1 K) in the file system and less (typically 512 bytes) in the buffer cache. However, when operating in the default mode the buffer cache will only cache a fixed number of directories even if you have a huge amount of memory. Turning on this sysctl allows the buffer cache to use the VM Page Cache to cache the directories, making all the memory available for caching directories. However, the minimum in-core memory used to cache a directory is the physical page size (typically 4 K) rather than 512  bytes. We recommend turning this option on if you are running any services which manipulate large numbers of files. Such services can include web caches, large mail systems, and news systems. Turning on this option will generally not reduce performance even with the wasted memory but you should experiment to find out.


6.12.1.2 vfs.write_behind

The vfs.write_behind sysctl variable defaults to 1 (on). This tells the file system to issue media writes as full clusters are collected, which typically occurs when writing large sequential files. The idea is to avoid saturating the buffer cache with dirty buffers when it would not benefit I/O performance. However, this may stall processes and under certain circumstances you may wish to turn it off.


6.12.1.3 vfs.hirunningspace

The vfs.hirunningspace sysctl variable determines how much outstanding write I/O may be queued to disk controllers system-wide at any given instance. The default is usually sufficient but on machines with lots of disks you may want to bump it up to four or five megabytes. Note that setting too high a value (exceeding the buffer cache's write threshold) can lead to extremely bad clustering performance. Do not set this value arbitrarily high! Higher write values may add latency to reads occurring at the same time.

There are various other buffer-cache and VM page cache related sysctls. We do not recommend modifying these values. As of FreeBSD 4.3, the VM system does an extremely good job of automatically tuning itself.


6.12.1.4 vm.swap_idle_enabled

The vm.swap_idle_enabled sysctl variable is useful in large multi-user systems where you have lots of users entering and leaving the system and lots of idle processes. Such systems tend to generate a great deal of continuous pressure on free memory reserves. Turning this feature on and tweaking the swapout hysteresis (in idle seconds) via vm.swap_idle_threshold1 and vm.swap_idle_threshold2 allows you to depress the priority of memory pages associated with idle processes more quickly then the normal pageout algorithm. This gives a helping hand to the pageout daemon. Do not turn this option on unless you need it, because the tradeoff you are making is essentially pre-page memory sooner rather than later; thus eating more swap and disk bandwidth. In a small system this option will have a determinable effect but in a large system that is already doing moderate paging this option allows the VM system to stage whole processes into and out of memory easily.


6.12.1.5 hw.ata.wc

FreeBSD 4.3 flirted with turning off IDE write caching. This reduced write bandwidth to IDE disks but was considered necessary due to serious data consistency issues introduced by hard drive vendors. The problem is that IDE drives lie about when a write completes. With IDE write caching turned on, IDE hard drives not only write data to disk out of order, but will sometimes delay writing some blocks indefinitely when under heavy disk loads. A crash or power failure may cause serious file system corruption. FreeBSD's default was changed to be safe. Unfortunately, the result was such a huge performance loss that we changed write caching back to on by default after the release. You should check the default on your system by observing the hw.ata.wc sysctl variable. If IDE write caching is turned off, you can turn it back on by setting the kernel variable back to 1. This must be done from the boot loader at boot time. Attempting to do it after the kernel boots will have no effect.

For more information, please see ata(4).


6.12.1.6 SCSI_DELAY (kern.cam.scsi_delay)

The SCSI_DELAY kernel config may be used to reduce system boot times. The defaults are fairly high and can be responsible for 15+ seconds of delay in the boot process. Reducing it to 5 seconds usually works (especially with modern drives). Newer versions of FreeBSD (5.0+) should use the kern.cam.scsi_delay boot time tunable. The tunable, and kernel config option accept values in terms of milliseconds and not seconds.


6.12.2 Soft Updates

The tunefs(8) program can be used to fine-tune a file system. This program has many different options, but for now we are only concerned with toggling Soft Updates on and off, which is done by:

# tunefs -n enable /filesystem
# tunefs -n disable /filesystem

A filesystem cannot be modified with tunefs(8) while it is mounted. A good time to enable Soft Updates is before any partitions have been mounted, in single-user mode.

Note: As of FreeBSD 4.5, it is possible to enable Soft Updates at filesystem creation time, through use of the -U option to newfs(8).

Soft Updates drastically improves meta-data performance, mainly file creation and deletion, through the use of a memory cache. We recommend to use Soft Updates on all of your file systems. There are two downsides to Soft Updates that you should be aware of: First, Soft Updates guarantees filesystem consistency in the case of a crash but could very easily be several seconds (even a minute!) behind updating the physical disk. If your system crashes you may lose more work than otherwise. Secondly, Soft Updates delays the freeing of filesystem blocks. If you have a filesystem (such as the root filesystem) which is almost full, performing a major update, such as make installworld, can cause the filesystem to run out of space and the update to fail.


6.12.2.1 More Details about Soft Updates

There are two traditional approaches to writing a file systems meta-data back to disk. (Meta-data updates are updates to non-content data like inodes or directories.)

Historically, the default behavior was to write out meta-data updates synchronously. If a directory had been changed, the system waited until the change was actually written to disk. The file data buffers (file contents) were passed through the buffer cache and backed up to disk later on asynchronously. The advantage of this implementation is that it operates safely. If there is a failure during an update, the meta-data are always in a consistent state. A file is either created completely or not at all. If the data blocks of a file did not find their way out of the buffer cache onto the disk by the time of the crash, fsck(8) is able to recognize this and repair the filesystem by setting the file length to 0. Additionally, the implementation is clear and simple. The disadvantage is that meta-data changes are slow. An rm -r, for instance, touches all the files in a directory sequentially, but each directory change (deletion of a file) will be written synchronously to the disk. This includes updates to the directory itself, to the inode table, and possibly to indirect blocks allocated by the file. Similar considerations apply for unrolling large hierarchies (tar -x).

The second case is asynchronous meta-data updates. This is the default for Linux/ext2fs and mount -o async for *BSD ufs. All meta-data updates are simply being passed through the buffer cache too, that is, they will be intermixed with the updates of the file content data. The advantage of this implementation is there is no need to wait until each meta-data update has been written to disk, so all operations which cause huge amounts of meta-data updates work much faster than in the synchronous case. Also, the implementation is still clear and simple, so there is a low risk for bugs creeping into the code. The disadvantage is that there is no guarantee at all for a consistent state of the filesystem. If there is a failure during an operation that updated large amounts of meta-data (like a power failure, or someone pressing the reset button), the filesystem will be left in an unpredictable state. There is no opportunity to examine the state of the filesystem when the system comes up again; the data blocks of a file could already have been written to the disk while the updates of the inode table or the associated directory were not. It is actually impossible to implement a fsck which is able to clean up the resulting chaos (because the necessary information is not available on the disk). If the filesystem has been damaged beyond repair, the only choice is to use newfs(8) on it and restore it from backup.

The usual solution for this problem was to implement dirty region logging, which is also referred to as journaling, although that term is not used consistently and is occasionally applied to other forms of transaction logging as well. Meta-data updates are still written synchronously, but only into a small region of the disk. Later on they will be moved to their proper location. Because the logging area is a small, contiguous region on the disk, there are no long distances for the disk heads to move, even during heavy operations, so these operations are quicker than synchronous updates. Additionally the complexity of the implementation is fairly limited, so the risk of bugs being present is low. A disadvantage is that all meta-data are written twice (once into the logging region and once to the proper location) so for normal work, a performance ``pessimization'' might result. On the other hand, in case of a crash, all pending meta-data operations can be quickly either rolled-back or completed from the logging area after the system comes up again, resulting in a fast filesystem startup.

Kirk McKusick, the developer of Berkeley FFS, solved this problem with Soft Updates: all pending meta-data updates are kept in memory and written out to disk in a sorted sequence (``ordered meta-data updates''). This has the effect that, in case of heavy meta-data operations, later updates to an item ``catch'' the earlier ones if the earlier ones are still in memory and have not already been written to disk. So all operations on, say, a directory are generally performed in memory before the update is written to disk (the data blocks are sorted according to their position so that they will not be on the disk ahead of their meta-data). If the system crashes, this causes an implicit ``log rewind'': all operations which did not find their way to the disk appear as if they had never happened. A consistent filesystem state is maintained that appears to be the one of 30 to 60 seconds earlier. The algorithm used guarantees that all resources in use are marked as such in their appropriate bitmaps: blocks and inodes. After a crash, the only resource allocation error that occurs is that resources are marked as ``used'' which are actually ``free''. fsck(8) recognizes this situation, and frees the resources that are no longer used. It is safe to ignore the dirty state of the filesystem after a crash by forcibly mounting it with mount -f. In order to free resources that may be unused, fsck(8) needs to be run at a later time. This is the idea behind the background fsck: at system startup time, only a snapshot of the filesystem is recorded. The fsck can be run later on. All file systems can then be mounted ``dirty'', so the system startup proceeds in multiuser mode. Then, background fscks will be scheduled for all file systems where this is required, to free resources that may be unused. (File systems that do not use Soft Updates still need the usual foreground fsck though.)

The advantage is that meta-data operations are nearly as fast as asynchronous updates (i.e. faster than with logging, which has to write the meta-data twice). The disadvantages are the complexity of the code (implying a higher risk for bugs in an area that is highly sensitive regarding loss of user data), and a higher memory consumption. Additionally there are some idiosyncrasies one has to get used to. After a crash, the state of the filesystem appears to be somewhat ``older''. In situations where the standard synchronous approach would have caused some zero-length files to remain after the fsck, these files do not exist at all with a Soft Updates filesystem because neither the meta-data nor the file contents have ever been written to disk. Disk space is not released until the updates have been written to disk, which may take place some time after running rm. This may cause problems when installing large amounts of data on a filesystem that does not have enough free space to hold all the files twice.


6.13 Tuning Kernel Limits


6.13.1 File/Process Limits

6.13.1.1 kern.maxfiles

kern.maxfiles can be raised or lowered based upon your system requirements. This variable indicates the maximum number of file descriptors on your system. When the file descriptor table is full, ``file: table is full'' will show up repeatedly in the system message buffer, which can be viewed with the dmesg command.

Each open file, socket, or fifo uses one file descriptor. A large-scale production server may easily require many thousands of file descriptors, depending on the kind and number of services running concurrently.

kern.maxfile's default value is dictated by the MAXUSERS option in your kernel configuration file. kern.maxfiles grows proportionally to the value of MAXUSERS. When compiling a custom kernel, it is a good idea to set this kernel configuration option according to the uses of your system. From this number, the kernel is given most of its pre-defined limits. Even though a production machine may not actually have 256 users connected at once, the resources needed may be similar to a high-scale web server.

Note: As of FreeBSD 4.5, setting MAXUSERS to 0 in your kernel configuration file will choose a reasonable default value based on the amount of RAM present in your system.


6.13.1.2 kern.ipc.somaxconn

The kern.ipc.somaxconn sysctl variable limits the size of the listen queue for accepting new TCP connections. The default value of 128 is typically too low for robust handling of new connections in a heavily loaded web server environment. For such environments, it is recommended to increase this value to 1024 or higher. The service daemon may itself limit the listen queue size (e.g. sendmail(8), or Apache) but will often have a directive in its configuration file to adjust the queue size. Large listen queues also do a better job of avoiding Denial of Service (DoS) attacks.


6.13.2 Network Limits

The NMBCLUSTERS kernel configuration option dictates the amount of network Mbufs available to the system. A heavily-trafficked server with a low number of Mbufs will hinder FreeBSD's ability. Each cluster represents approximately 2 K of memory, so a value of 1024 represents 2 megabytes of kernel memory reserved for network buffers. A simple calculation can be done to figure out how many are needed. If you have a web server which maxes out at 1000 simultaneous connections, and each connection eats a 16 K receive and 16 K send buffer, you need approximately 32 MB worth of network buffers to cover the web server. A good rule of thumb is to multiply by 2, so 2x32 MB / 2 KB = 64 MB / 2 kB = 32768. We recommend values between 4096 and 32768 for machines with greater amounts of memory. Under no circumstances should you specify an arbitrarily high value for this parameter as it could lead to a boot time crash. The -m option to netstat(1) may be used to observe network cluster use.

kern.ipc.nmbclusters loader tunable should be used to tune this at boot time. Only older versions of FreeBSD will require you to use the NMBCLUSTERS kernel config(8) option.

For busy servers that make extensive use of the sendfile(2) system call, it may be necessary to increase the number of sendfile(2) buffers via the NSFBUFS kernel configuration option or by setting its value in /boot/loader.conf (see loader(8) for details). A common indicator that this parameter needs to be adjusted is when processes are seen in the ``sfbufa'' state. The sysctl variable kern.ipc.nsfbufs is a read-only glimpse at the kernel configured variable. This parameter nominally scales with kern.maxusers, however it may be necessary to tune accordingly.

Important: Even though a socket has been marked as non-blocking, calling sendfile(2) on the non-blocking socket may result in the sendfile(2) call blocking until enough struct sf_buf's are made available.


6.13.2.1 net.inet.ip.portrange.*

The net.inet.ip.portrange.* sysctl variables control the port number ranges automatically bound to TCP and UDP sockets. There are three ranges: a low range, a default range, and a high range. Most network programs use the default range which is controlled by the net.inet.ip.portrange.first and net.inet.ip.portrange.last, which default to 1024 and 5000, respectively. Bound port ranges are used for outgoing connections, and it is possible to run the system out of ports under certain circumstances. This most commonly occurs when you are running a heavily loaded web proxy. The port range is not an issue when running servers which handle mainly incoming connections, such as a normal web server, or has a limited number of outgoing connections, such as a mail relay. For situations where you may run yourself out of ports, it is recommended to increase net.inet.ip.portrange.last modestly. A value of 10000, 20000 or 30000 may be reasonable. You should also consider firewall effects when changing the port range. Some firewalls may block large ranges of ports (usually low-numbered ports) and expect systems to use higher ranges of ports for outgoing connections -- for this reason it is recommended that net.inet.ip.portrange.first be lowered.


6.13.2.2 TCP Bandwidth Delay Product

The TCP Bandwidth Delay Product Limiting is similar to TCP/Vegas in NetBSD. It can be enabled by setting net.inet.tcp.inflight_enable sysctl variable to 1. The system will attempt to calculate the bandwidth delay product for each connection and limit the amount of data queued to the network to just the amount required to maintain optimum throughput.

This feature is useful if you are serving data over modems, Gigabit Ethernet, or even high speed WAN links (or any other link with a high bandwidth delay product), especially if you are also using window scaling or have configured a large send window. If you enable this option, you should also be sure to set net.inet.tcp.inflight_debug to 0 (disable debugging), and for production use setting net.inet.tcp.inflight_min to at least 6144 may be beneficial. However, note that setting high minimums may effectively disable bandwidth limiting depending on the link. The limiting feature reduces the amount of data built up in intermediate route and switch packet queues as well as reduces the amount of data built up in the local host's interface queue. With fewer packets queued up, interactive connections, especially over slow modems, will also be able to operate with lower Round Trip Times. However, note that this feature only effects data transmission (uploading / server side). It has no effect on data reception (downloading).

Adjusting net.inet.tcp.inflight_stab is not recommended. This parameter defaults to 20, representing 2 maximal packets added to the bandwidth delay product window calculation. The additional window is required to stabilize the algorithm and improve responsiveness to changing conditions, but it can also result in higher ping times over slow links (though still much lower than you would get without the inflight algorithm). In such cases, you may wish to try reducing this parameter to 15, 10, or 5; and may also have to reduce net.inet.tcp.inflight_min (for example, to 3500) to get the desired effect. Reducing these parameters should be done as a last resort only.


6.14 Adding Swap Space

No matter how well you plan, sometimes a system does not run as you expect. If you find you need more swap space, it is simple enough to add. You have three ways to increase swap space: adding a new hard drive, enabling swap over NFS, and creating a swap file on an existing partition.


6.14.1 Swap on a New Hard Drive

The best way to add swap, of course, is to use this as an excuse to add another hard drive. You can always use another hard drive, after all. If you can do this, go reread the discussion of swap space from the Initial Configuration section of the Handbook for some suggestions on how to best arrange your swap.


6.14.2 Swapping over NFS

Swapping over NFS is only recommended if you do not have a local hard disk to swap to. Swapping over NFS is slow and inefficient in versions of FreeBSD prior to 4.X. It is reasonably fast and efficient in 4.0-RELEASE and newer. Even with newer versions of FreeBSD, NFS swapping will be limited by the available network bandwidth and puts an additional burden on the NFS server.


6.14.3 Swapfiles

You can create a file of a specified size to use as a swap file. In our example here we will use a 64MB file called /usr/swap0. You can use any name you want, of course.

Example 6-1. Creating a Swapfile on FreeBSD 4.X

  1. Be certain that your kernel configuration includes the vnode driver. It is not in recent versions of GENERIC.

    pseudo-device   vn 1   #Vnode driver (turns a file into a device)
    
  2. Create a vn-device:

    # cd /dev
    # sh MAKEDEV vn0
    
  3. Create a swapfile (/usr/swap0):

    # dd if=/dev/zero of=/usr/swap0 bs=1024k count=64
    
  4. Set proper permissions on (/usr/swap0):

    # chmod 0600 /usr/swap0
    
  5. Enable the swap file in /etc/rc.conf:

    swapfile="/usr/swap0"   # Set to name of swapfile if aux swapfile desired.
    
  6. Reboot the machine or to enable the swap file immediately, type:

    # vnconfig -e /dev/vn0b /usr/swap0 swap
    

Example 6-2. Creating a Swapfile on FreeBSD 5.X

  1. Be certain that your kernel configuration includes the memory disk driver (md(4)). It is default in GENERIC kernel.

    device   md   # Memory "disks"
    
  2. Create a swapfile (/usr/swap0):

    # dd if=/dev/zero of=/usr/swap0 bs=1024k count=64
    
  3. Set proper permissions on (/usr/swap0):

    # chmod 0600 /usr/swap0
    
  4. Enable the swap file in /etc/rc.conf:

    swapfile="/usr/swap0"   # Set to name of swapfile if aux swapfile desired.
    
  5. Reboot the machine or to enable the swap file immediately, type:

    # mdconfig -a -t vnode -f /usr/swap0 -u 0 && swapon /dev/md0
    

6.15 Power and Resource Management

Written by Hiten Pandya and Tom Rhodes.

It is very important to utilize hardware resources in an efficient manner. Before ACPI was introduced, it was very difficult and inflexible for operating systems to manage the power usage and thermal properties of a system. The hardware was controlled by some sort of BIOS embedded interface, such as Plug and Play BIOS (PNPBIOS), or Advanced Power Management (APM) and so on. Power and Resource Management is one of the key components of a modern operating system. For example, you may want an operating system to monitor system limits (and possibly alert you) in case your system temperature increased unexpectedly.

In this section of the FreeBSD Handbook, we will provide comprehensive information about ACPI. References will be provided for further reading at the end. Please be aware that ACPI is available on FreeBSD 5.X and above systems as a default kernel module. For FreeBSD 4.9, ACPI can be enabled by adding the line device acpi to a kernel configuration and rebuilding.


6.15.1 What Is ACPI?

Advanced Configuration and Power Interface (ACPI) is a standard written by an alliance of vendors to provide a standard interface for hardware resources and power management (hence the name). It is a key element in Operating System-directed configuration and Power Management, i.e.: it provides more control and flexibility to the operating system (OS). Modern systems ``stretched'' the limits of the current Plug and Play interfaces (such as APM, which is used in FreeBSD 4.X), prior to the introduction of ACPI. ACPI is the direct successor to APM (Advanced Power Management).


6.15.2 Shortcomings of Advanced Power Management (APM)

The Advanced Power Management (APM) facility control's the power usage of a system based on its activity. The APM BIOS is supplied by the (system) vendor and it is specific to the hardware platform. An APM driver in the OS mediates access to the APM Software Interface, which allows management of power levels.

There are four major problems in APM. Firstly, power management is done by the (vendor-specific) BIOS, and the OS does not have any knowledge of it. One example of this, is when the user sets idle-time values for a hard drive in the APM BIOS, that when exceeded, it (BIOS) would spin down the hard drive, without the consent of the OS. Secondly, the APM logic is embedded in the BIOS, and it operates outside the scope of the OS. This means users can only fix problems in their APM BIOS by flashing a new one into the ROM; which, is a very dangerous procedure, and if it fails, it could leave the system in an unrecoverable state. Thirdly, APM is a vendor-specific technology, which, means that there is a lot or parity (duplication of efforts) and bugs found in one vendor's BIOS, may not be solved in others. Last but not the least, the APM BIOS did not have enough room to implement a sophisticated power policy, or one that can adapt very well to the purpose of the machine.

Plug and Play BIOS (PNPBIOS) was unreliable in many situations. PNPBIOS is 16-bit technology, so the OS has to use 16-bit emulation in order to ``interface'' with PNPBIOS methods.

The FreeBSD APM driver is documented in the apm(4) manual page.


6.15.3 Configuring ACPI

The acpi.ko driver is loaded by default at start up by the loader(8) and should not be compiled into the kernel. The reasoning behind this is that modules are easier to work with, say if switching to another acpi.ko without doing a kernel rebuild. This has the advantage of making testing easier. Another reason is that starting ACPI after a system has been brought up is not too useful, and in some cases can be fatal. In doubt, just disable ACPI all together. This driver should not and can not be unloaded because the system bus uses it for various hardware interactions. ACPI can be disabled with the acpiconf(8) utility. In fact most of the interaction with ACPI can be done via acpiconf(8). Basically this means, if anything about ACPI is in the dmesg(8) output, then most likely it is already running.

Note: ACPI and APM cannot coexist and should be used separately. The last one to load will terminate if the driver notices the other running.

In the simplest form, ACPI can be used to put the system into a sleep mode with acpiconf(8), the -s flag, and a 1-5 option. Most users will only need 1. Option 5 will do a soft-off which is the same action as:

# halt -p

The other options are available. Check out the acpiconf(8) manual page for more information.


6.15.4 Debugging and Disabling ACPI

Almost everything in ACPI is transparent, until it does not work. That is usually when you as a user will know there is something not working properly. The acpi(4) driver supports many debugging options, it is even possible to selectively disable some parts of the ACPI system. For more information about debugging facilities, read the acpi(4) manual page.

Sometimes for various reasons, the acpi.ko module must be unloaded. This can only be done at boot time by the loader(8). You can type at loader(8) prompt the command unset acpi_load each time you boot the system, or to stop the autoloading of the acpi(4) driver add the following line to the /boot/loader.conf file:

exec="unset acpi_load"

FreeBSD 5.1-RELEASE and later come with a boot-time menu that controls how FreeBSD is booted. One of the proposed options is to turn off ACPI. So to disable ACPI just select 2. Boot FreeBSD with ACPI disabled in the menu.


Chapter 7 The FreeBSD Booting Process

7.1 Synopsis

The process of starting a computer and loading the operating system is referred to as ``the bootstrap process'', or simply ``booting''. FreeBSD's boot process provides a great deal of flexibility in customizing what happens when you start the system, allowing you to select from different operating systems installed on the same computer, or even different versions of the same operating system or installed kernel.

This chapter details the configuration options you can set and how to customize the FreeBSD boot process. This includes everything that happens until the FreeBSD kernel has started, probed for devices, and started init(8). If you are not quite sure when this happens, it occurs when the text color changes from bright white to grey.

After reading this chapter, you will know:

  • What the components of the FreeBSD bootstrap system are, and how they interact.

  • The options you can give to the components in the FreeBSD bootstrap to control the boot process.

  • The basics of device.hints(5).

x86 Only: This chapter only describes the boot process for FreeBSD running on Intel x86 systems.


7.2 The Booting Problem

Turning on a computer and starting the operating system poses an interesting dilemma. By definition, the computer does not know how to do anything until the operating system is started. This includes running programs from the disk. So if the computer can not run a program from the disk without the operating system, and the operating system programs are on the disk, how is the operating system started?

This problem parallels one in the book The Adventures of Baron Munchausen. A character had fallen part way down a manhole, and pulled himself out by grabbing his bootstraps, and lifting. In the early days of computing the term bootstrap was applied to the mechanism used to load the operating system, which has become shortened to ``booting''.

On x86 hardware the Basic Input/Output System (BIOS) is responsible for loading the operating system. To do this, the BIOS looks on the hard disk for the Master Boot Record (MBR), which must be located on a specific place on the disk. The BIOS has enough knowledge to load and run the MBR, and assumes that the MBR can then carry out the rest of the tasks involved in loading the operating system.

If you only have one operating system installed on your disks then the standard MBR will suffice. This MBR searches for the first bootable slice on the disk, and then runs the code on that slice to load the remainder of the operating system.

If you have installed multiple operating systems on your disks then you can install a different MBR, one that can display a list of different operating systems, and allows you to choose the one to boot from. FreeBSD comes with one such MBR which can be installed, and other operating system vendors also provide alternative MBRs.

The remainder of the FreeBSD bootstrap system is divided into three stages. The first stage is run by the MBR, which knows just enough to get the computer into a specific state and run the second stage. The second stage can do a little bit more, before running the third stage. The third stage finishes the task of loading the operating system. The work is split into these three stages because the PC standards put limits on the size of the programs that can be run at stages one and two. Chaining the tasks together allows FreeBSD to provide a more flexible loader.

The kernel is then started and it begins to probe for devices and initialize them for use. Once the kernel boot process is finished, the kernel passes control to the user process init(8), which then makes sure the disks are in a usable state. init(8) then starts the user-level resource configuration which mounts file systems, sets up network cards to communicate on the network, and generally starts all the processes that usually are run on a FreeBSD system at startup.


7.3 The MBR, and Boot Stages One, Two, and Three

7.3.1 MBR, /boot/boot0

The FreeBSD MBR is located in /boot/boot0. This is a copy of the MBR, as the real MBR must be placed on a special part of the disk, outside the FreeBSD area.

boot0 is very simple, since the program in the MBR can only be 512 bytes in size. If you have installed the FreeBSD MBR and have installed multiple operating systems on your hard disks then you will see a display similar to this one at boot time:

Example 7-1. boot0 Screenshot

F1 DOS
F2 FreeBSD
F3 Linux
F4 ??
F5 Drive 1

Default: F2

Other operating systems, in particular Windows 95, have been known to overwrite an existing MBR with their own. If this happens to you, or you want to replace your existing MBR with the FreeBSD MBR then use the following command:

# fdisk -B -b /boot/boot0 device

Where device is the device that you boot from, such as ad0 for the first IDE disk, ad2 for the first IDE disk on a second IDE controller, da0 for the first SCSI disk, and so on.

If you are a Linux user, however, and prefer that LILO control the boot process, you can edit the /etc/lilo.conf file for FreeBSD, or select Leave The Master Boot Record Untouched during the FreeBSD installation process. If you have installed the FreeBSD boot manager, you can boot back into Linux and modify the LILO configuration file /etc/lilo.conf and add the following option:

other=/dev/hdXY
table=/dev/hdb
loader=/boot/chain.b
label=FreeBSD

which will permit the booting of FreeBSD and Linux via LILO. In our example, we use XY to determine drive number and partition. If you are using a SCSI drive, you will want to change /dev/hdXY to read something similar to /dev/sdXY, which again uses the XY syntax. The loader=/boot/chain.b can be omitted if you have both operating systems on the same drive. You can now run /sbin/lilo -v to commit your new changes to the system, this should be verified with screen messages.


7.3.2 Stage One, /boot/boot1, and Stage Two, /boot/boot2

Conceptually the first and second stages are part of the same program, on the same area of the disk. Because of space constraints they have been split into two, but you would always install them together.

They are found on the boot sector of the boot slice, which is where boot0, or any other program on the MBR expects to find the program to run to continue the boot process. The files in the /boot directory are copies of the real files, which are stored outside of the FreeBSD file system.

boot1 is very simple, since it too can only be 512 bytes in size, and knows just enough about the FreeBSD disklabel, which stores information about the slice, to find and execute boot2.

boot2 is slightly more sophisticated, and understands the FreeBSD file system enough to find files on it, and can provide a simple interface to choose the kernel or loader to run.

Since the loader is much more sophisticated, and provides a nice easy-to-use boot configuration, boot2 usually runs it, but previously it was tasked to run the kernel directly.

Example 7-2. boot2 Screenshot

>> FreeBSD/i386 BOOT
Default: 0:ad(0,a)/kernel
boot:

If you ever need to replace the installed boot1 and boot2 use disklabel(8).

# disklabel -B diskslice

Where diskslice is the disk and slice you boot from, such as ad0s1 for the first slice on the first IDE disk.

Dangerously Dedicated Mode: If you use just the disk name, such as ad0, in the disklabel(8) command you will create a dangerously dedicated disk, without slices. This is almost certainly not what you want to do, so make sure you double check the disklabel(8) command before you press Return.


7.3.3 Stage Three, /boot/loader

The loader is the final stage of the three-stage bootstrap, and is located on the file system, usually as /boot/loader.

The loader is intended as a user-friendly method for configuration, using an easy-to-use built-in command set, backed up by a more powerful interpreter, with a more complex command set.


7.3.3.1 Loader Program Flow

During initialization, the loader will probe for a console and for disks, and figure out what disk it is booting from. It will set variables accordingly, and an interpreter is started where user commands can be passed from a script or interactively.

The loader will then read /boot/loader.rc, which by default reads in /boot/defaults/loader.conf which sets reasonable defaults for variables and reads /boot/loader.conf for local changes to those variables. loader.rc then acts on these variables, loading whichever modules and kernel are selected.

Finally, by default, the loader issues a 10 second wait for key presses, and boots the kernel if it is not interrupted. If interrupted, the user is presented with a prompt which understands the easy-to-use command set, where the user may adjust variables, unload all modules, load modules, and then finally boot or reboot.


7.3.3.2 Loader Built-In Commands

These are the most commonly used loader commands. For a complete discussion of all available commands, please see loader(8).

autoboot seconds

Proceeds to boot the kernel if not interrupted within the time span given, in seconds. It displays a countdown, and the default time span is 10 seconds.

boot [-options] [kernelname]

Immediately proceeds to boot the kernel, with the given options, if any, and with the kernel name given, if it is.

boot-conf

Goes through the same automatic configuration of modules based on variables as what happens at boot. This only makes sense if you use unload first, and change some variables, most commonly kernel.

help [topic]

Shows help messages read from /boot/loader.help. If the topic given is index, then the list of available topics is given.

include filename ...

Processes the file with the given filename. The file is read in, and interpreted line by line. An error immediately stops the include command.

load [-t type] filename

Loads the kernel, kernel module, or file of the type given, with the filename given. Any arguments after filename are passed to the file.

ls [-l] [path]

Displays a listing of files in the given path, or the root directory, if the path is not specified. If -l is specified, file sizes will be shown too.

lsdev [-v]

Lists all of the devices from which it may be possible to load modules. If -v is specified, more details are printed.

lsmod [-v]

Displays loaded modules. If -v is specified, more details are shown.

more filename

Displays the files specified, with a pause at each LINES displayed.

reboot

Immediately reboots the system.

set variable, set variable=value

Sets the loader's environment variables.

unload

Removes all loaded modules.


7.3.3.3 Loader Examples

Here are some practical examples of loader usage:

  • To simply boot your usual kernel, but in single-user mode:

    boot -s
    
  • To unload your usual kernel and modules, and then load just your old (or another) kernel:

    unload
    load kernel.old
    

    You can use kernel.GENERIC to refer to the generic kernel that comes on the install disk, or kernel.old to refer to your previously installed kernel (when you have upgraded or configured your own kernel, for example).

    Note: Use the following to load your usual modules with another kernel:

    unload
    set kernel="kernel.old"
    boot-conf
    
  • To load a kernel configuration script (an automated script which does the things you would normally do in the kernel boot-time configurator):

    load -t userconfig_script /boot/kernel.conf
    

7.4 Kernel Interaction During Boot

Once the kernel is loaded by either loader (as usual) or boot2 (bypassing the loader), it examines its boot flags, if any, and adjusts its behavior as necessary.


7.4.1 Kernel Boot Flags

Here are the more common boot flags:

-a

during kernel initialization, ask for the device to mount as the root file system.

-C

boot from CDROM.

-c

run UserConfig, the boot-time kernel configurator

-s

boot into single-user mode

-v

be more verbose during kernel startup

Note: There are other boot flags, read boot(8) for more information on them.


7.5 Device Hints

Contributed by Tom Rhodes.

Note: This is a FreeBSD 5.0 and later feature which does not exist in earlier versions.

During initial system startup, the boot loader(8) will read the device.hints(5) file. This file stores kernel boot information known as variables, sometimes referred to as ``device hints''. These ``device hints'' are used by device drivers for device configuration.

Device hints may also be specified at the Stage 3 boot loader prompt. Variables can be added using set, removed with unset, and viewed with the show commands. Variables set in the /boot/device.hints file can be overridden here also. Device hints entered at the boot loader are not permanent and will be forgotten on the next reboot.

Once the system is booted, the kenv(1) command can be used to dump all of the variables.

The syntax for the /boot/device.hints file is one variable per line, using the standard hash ``#'' as comment markers. Lines are constructed as follows:

hint.driver.unit.keyword="value"

The syntax for the Stage 3 boot loader is:

set hint.driver.unit.keyword=value

driver is the device driver name, unit is the device driver unit number, and keyword is the hint keyword. The keyword may consist of the following options:

  • at: specifies the bus which the device is attached to.

  • port: specifies the start address of the I/O to be used.

  • irq: specifies the interrupt request number to be used.

  • drq: specifies the DMA channel number.

  • maddr: specifies the physical memory address occupied by the device.

  • flags: sets various flag bits for the device.

  • disabled: if set to 1 the device is disabled.

Device drivers may accept (or require) more hints not listed here, viewing their manual page is recommended. For more information, consult the device.hints(5), kenv(1), loader.conf(5), and loader(8) manual pages.


7.6 Init: Process Control Initialization

Once the kernel has finished booting, it passes control to the user process init(8), which is located at /sbin/init, or the program path specified in the init_path variable in loader.


7.6.1 Automatic Reboot Sequence

The automatic reboot sequence makes sure that the file systems available on the system are consistent. If they are not, and fsck(8) cannot fix the inconsistencies, init(8) drops the system into single-user mode for the system administrator to take care of the problems directly.


7.6.2 Single-User Mode

This mode can be reached through the automatic reboot sequence, or by the user booting with the -s option or setting the boot_single variable in loader.

It can also be reached by calling shutdown(8) without the reboot (-r) or halt (-h) options, from multi-user mode.

If the system console is set to insecure in /etc/ttys, then the system prompts for the root password before initiating single-user mode.

Example 7-3. An Insecure Console in /etc/ttys

# name  getty                           type    status          comments
#
# If console is marked "insecure", then init will ask for the root password
# when going to single-user mode.
console none                            unknown off insecure

Note: An insecure console means that you consider your physical security to the console to be insecure, and want to make sure only someone who knows the root password may use single-user mode, and it does not mean that you want to run your console insecurely. Thus, if you want security, choose insecure, not secure.


7.6.3 Multi-User Mode

If init(8) finds your file systems to be in order, or once the user has finished in single-user mode, the system enters multi-user mode, in which it starts the resource configuration of the system.


7.6.3.1 Resource Configuration (rc)

The resource configuration system reads in configuration defaults from /etc/defaults/rc.conf, and system-specific details from /etc/rc.conf, and then proceeds to mount the system file systems mentioned in /etc/fstab, start up networking services, start up miscellaneous system daemons, and finally runs the startup scripts of locally installed packages.

The rc(8) manual page is a good reference to the resource configuration system, as is examining the scripts themselves.


7.7 Shutdown Sequence

Upon controlled shutdown, via shutdown(8), init(8) will attempt to run the script /etc/rc.shutdown, and then proceed to send all processes the TERM signal, and subsequently the KILL signal to any that do not terminate timely.

To power down a FreeBSD machine on architectures and systems that support power management, simply use the command shutdown -p now to turn the power off immediately. To just reboot a FreeBSD system, just use shutdown -r now. You need to be root or a member of operator group to run shutdown(8). The halt(8) and reboot(8) commands can also be used, please refer to their manual pages and to shutdown(8)'s one for more informations.

Note: Power management requires acpi(4) support in the kernel or loaded as module for FreeBSD 5.X and apm(4) support for FreeBSD 4.X.


Chapter 8 Users and Basic Account Management

Contributed by Neil Blakey-Milner.

8.1 Synopsis

FreeBSD allows multiple users to use the computer at the same time. Obviously, only one of those users can be sitting in front of the screen and keyboard at any one time [5], but any number of users can log in through the network to get their work done. To use the system every user must have an account.

After reading this chapter, you will know:

  • The differences between the various user accounts on a FreeBSD system.

  • How to add user accounts.

  • How to remove user accounts.

  • How to change account details, such as the user's full name, or preferred shell.

  • How to set limits on a per-account basis, to control the resources such as memory and CPU time that accounts and groups of accounts are allowed to access.

  • How to use groups to make account management easier.

Before reading this chapter, you should:

  • Understand the basics of UNIX and FreeBSD (Chapter 3).


8.2 Introduction

All access to the system is achieved via accounts, and all processes are run by users, so user and account management are of integral importance on FreeBSD systems.

Every account on a FreeBSD system has certain information associated with it to identify the account.

User name

The user name as it would be typed at the login: prompt. User names must be unique across the computer; you may not have two users with the same user name. There are a number of rules for creating valid user names, documented in passwd(5); you would typically use user names that consist of eight or fewer all lower case characters.

Password

Each account has a password associated with it. The password may be blank, in which case no password will be required to access the system. This is normally a very bad idea; every account should have a password.

User ID (UID)

The UID is a number, traditionally from 0 to 65535[6], used to uniquely identify the user to the system. Internally, FreeBSD uses the UID to identify users--any FreeBSD commands that allow you to specify a user name will convert it to the UID before working with it. This means that you can have several accounts with different user names but the same UID. As far as FreeBSD is concerned these accounts are one user. It is unlikely you will ever need to do this.

Group ID (GID)

The GID is a number, traditionally from 0 to 65535[6], used to uniquely identify the primary group that the user belongs to. Groups are a mechanism for controlling access to resources based on a user's GID rather than their UID. This can significantly reduce the size of some configuration files. A user may also be in more than one group.

Login class

Login classes are an extension to the group mechanism that provide additional flexibility when tailoring the system to different users.

Password change time

By default FreeBSD does not force users to change their passwords periodically. You can enforce this on a per-user basis, forcing some or all of your users to change their passwords after a certain amount of time has elapsed.

Account expiry time

By default FreeBSD does not expire accounts. If you are creating accounts that you know have a limited lifespan, for example, in a school where you have accounts for the students, then you can specify when the account expires. After the expiry time has elapsed the account cannot be used to log in to the system, although the account's directories and files will remain.

User's full name

The user name uniquely identifies the account to FreeBSD, but does not necessarily reflect the user's real name. This information can be associated with the account.

Home directory

The home directory is the full path to a directory on the system in which the user will start when logging on to the system. A common convention is to put all user home directories under /home/username or /usr/home/username. The user would store their personal files in their home directory, and any directories they may create in there.

User shell

The shell provides the default environment users use to interact with the system. There are many different kinds of shells, and experienced users will have their own preferences, which can be reflected in their account settings.

There are three main types of accounts: the Superuser, system users, and user accounts. The Superuser account, usually called root, is used to manage the system with no limitations on privileges. System users run services. Finally, user accounts are used by real people, who log on, read mail, and so forth.


8.3 The Superuser Account

The superuser account, usually called root, comes preconfigured to facilitate system administration, and should not be used for day-to-day tasks like sending and receiving mail, general exploration of the system, or programming.

This is because the superuser, unlike normal user accounts, can operate without limits, and misuse of the superuser account may result in spectacular disasters. User accounts are unable to destroy the system by mistake, so it is generally best to use normal user accounts whenever possible, unless you especially need the extra privilege.

You should always double and triple-check commands you issue as the superuser, since an extra space or missing character can mean irreparable data loss.

So, the first thing you should do after reading this chapter is to create an unprivileged user account for yourself for general usage if you have not already. This applies equally whether you are running a multi-user or single-user machine. Later in this chapter, we discuss how to create additional accounts, and how to change between the normal user and superuser.


8.4 System Accounts

System users are those used to run services such as DNS, mail, web servers, and so forth. The reason for this is security; if all services ran as the superuser, they could act without restriction.

Examples of system users are daemon, operator, bind (for the Domain Name Service), and news. Often sysadmins create httpd to run web servers they install.

nobody is the generic unprivileged system user. However, it is important to keep in mind that the more services that use nobody, the more files and processes that user will become associated with, and hence the more privileged that user becomes.


8.5 User Accounts

User accounts are the primary means of access for real people to the system, and these accounts insulate the user and the environment, preventing the users from damaging the system or other users, and allowing users to customize their environment without affecting others.

Every person accessing your system should have a unique user account. This allows you to find out who is doing what, prevent people from clobbering each others' settings or reading each others' mail, and so forth.

Each user can set up their own environment to accommodate their use of the system, by using alternate shells, editors, key bindings, and language.


8.6 Modifying Accounts

There are a variety of different commands available in the UNIX environment to manipulate user accounts. The most common commands are summarized below, followed by more detailed examples of their usage.

Command Summary
adduser(8) The recommended command-line application for adding new users.
rmuser(8) The recommended command-line application for removing users.
chpass(1) A flexible tool to change user database information.
passwd(1) The simple command-line tool to change user passwords.
pw(8) A powerful and flexible tool to modify all aspects of user accounts.

8.6.1 adduser

adduser(8) is a simple program for adding new users. It creates entries in the system passwd and group files. It will also create a home directory for the new user, copy in the default configuration files (``dotfiles'') from /usr/share/skel, and can optionally mail the new user a welcome message.

In FreeBSD 5.0, adduser(8) was rewritten from a Perl script to a shell script that acts as wrapper around pw(8), so its usage is slightly different on FreeBSD 4.X and FreeBSD 5.X.

To create the initial configuration file, use adduser -s -config_create. [7] Next, we configure adduser(8) defaults, and create our first user account, since using root for normal usage is evil and nasty.

Example 8-1. Configuring adduser and adding a user on FreeBSD 4.X

# adduser -v
Use option ``-silent'' if you don't want to see all warnings and questions.
Check /etc/shells
Check /etc/master.passwd
Check /etc/group
Enter your default shell: csh date no sh tcsh zsh [sh]: zsh
Your default shell is: zsh -> /usr/local/bin/zsh
Enter your default HOME partition: [/home]:
Copy dotfiles from: /usr/share/skel no [/usr/share/skel]: 
Send message from file: /etc/adduser.message no 
[/etc/adduser.message]: no
Do not send message
Use passwords (y/n) [y]: y

Write your changes to /etc/adduser.conf? (y/n) [n]: y

Ok, let's go.
Don't worry about mistakes. I will give you the chance later to correct any input.
Enter username [a-z0-9_-]: jru
Enter full name []: J. Random User
Enter shell csh date no sh tcsh zsh [zsh]: 
Enter home directory (full path) [/home/jru]: 
Uid [1001]: 
Enter login class: default []: 
Login group jru [jru]: 
Login group is ``jru''. Invite jru into other groups: guest no 
[no]: wheel
Enter password []: 
Enter password again []: 

Name:     jru
Password: ****
Fullname: J. Random User
Uid:      1001
Gid:      1001 (jru)
Class:    
Groups:   jru wheel
HOME:     /home/jru
Shell:    /usr/local/bin/zsh
OK? (y/n) [y]: y
Added user ``jru''
Copy files from /usr/share/skel to /home/jru
Add another user? (y/n) [y]: n
Goodbye!
#

In summary, we changed the default shell to zsh (an additional shell found in the Ports Collection), and turned off the sending of a welcome mail to added users. We then saved the configuration, created an account for jru, and made sure jru is in wheel group (so that she may assume the role of root with the su(1) command.)

Note: The password you type in is not echoed, nor are asterisks displayed. Make sure you do not mistype the password twice.

Note: Just use adduser(8) without arguments from now on, and you will not have to go through changing the defaults. If the program asks you to change the defaults, exit the program, and try the -s option.

Example 8-2. Adding a user on FreeBSD 5.X

# adduser
Username: jru
Full name: J. Random User
Uid (Leave empty for default):
Login group [jru]:
Login group is jru. Invite jru into other groups? []: wheel
Login class [default]:
Shell (sh csh tcsh zsh nologin) [sh]: zsh
Home directory [/home/jru]:
Use password-based authentication? [yes]:
Use an empty password? (yes/no) [no]:
Use a random password? (yes/no) [no]:
Enter password:
Enter password again:
Lock out the account after creation? [no]:
Username   : jru
Password   : ****
Full Name  : J. Random User
Uid        : 1001
Class      :
Groups     : jru wheel
Home       : /home/jru
Shell      : /usr/local/bin/zsh
Locked     : no
OK? (yes/no): yes
adduser: INFO: Successfully added (jru) to the user database.
Add another user? (yes/no): no
Goodbye!
#

8.6.2 rmuser

You can use rmuser(8) to completely remove a user from the system. rmuser(8) performs the following steps:

  1. Removes the user's crontab(1) entry (if any).

  2. Removes any at(1) jobs belonging to the user.

  3. Kills all processes owned by the user.

  4. Removes the user from the system's local password file.

  5. Removes the user's home directory (if it is owned by the user).

  6. Removes the incoming mail files belonging to the user from /var/mail.

  7. Removes all files owned by the user from temporary file storage areas such as /tmp.

  8. Finally, removes the username from all groups to which it belongs in /etc/group.

    Note: If a group becomes empty and the group name is the same as the username, the group is removed; this complements the per-user unique groups created by adduser(8).



rmuser(8) cannot be used to remove superuser accounts, since that is almost always an indication of massive destruction.

By default, an interactive mode is used, which attempts to make sure you know what you are doing.

Example 8-3. rmuser Interactive Account Removal

# rmuser jru
Matching password entry:
jru:*:1001:1001::0:0:J. Random User:/home/jru:/usr/local/bin/zsh
Is this the entry you wish to remove? y
Remove user's home directory (/home/jru)? y
Updating password file, updating databases, done.
Updating group file: trusted (removing group jru -- personal group is empty) done.
Removing user's incoming mail file /var/mail/jru: done.
Removing files belonging to jru from /tmp: done.
Removing files belonging to jru from /var/tmp: done.
Removing files belonging to jru from /var/tmp/vi.recover: done.
#

8.6.3 chpass

chpass(1) changes user database information such as passwords, shells, and personal information.

Only system administrators, as the superuser, may change other users' information and passwords with chpass(1).

When passed no options, aside from an optional username, chpass(1) displays an editor containing user information. When the user exists from the editor, the user database is updated with the new information.

Note: In FreeBSD 5.X, you will be asked for your password after exiting the editor if you are not the superuser.

Example 8-4. Interactive chpass by Superuser

#Changing user database information for jru.
Login: jru
Password: *
Uid [#]: 1001
Gid [# or name]: 1001
Change [month day year]:
Expire [month day year]:
Class:
Home directory: /home/jru
Shell: /usr/local/bin/zsh
Full Name: J. Random User
Office Location:
Office Phone:
Home Phone:
Other information:

The normal user can change only a small subset of this information, and only for themselves.

Example 8-5. Interactive chpass by Normal User

#Changing user database information for jru.
Shell: /usr/local/bin/zsh
Full Name: J. Random User
Office Location:
Office Phone:
Home Phone:
Other information:

Note: chfn(1) and chsh(1) are just links to chpass(1), as are ypchpass(1), ypchfn(1), and ypchsh(1). NIS support is automatic, so specifying the yp before the command is not necessary. If this is confusing to you, do not worry, NIS will be covered in Chapter 19.


8.6.4 passwd

passwd(1) is the usual way to change your own password as a user, or another user's password as the superuser.

Note: Before changing their password, users must type in their original password to prevent an unauthorized person from changing their password when the user is away from their console.

Example 8-6. Changing Your Password

% passwd
Changing local password for jru.
Old password:
New password:
Retype new password:
passwd: updating the database...
passwd: done

Example 8-7. Changing Another User's Password as the Superuser

# passwd jru
Changing local password for jru.
New password:
Retype new password:
passwd: updating the database...
passwd: done

Note: As with chpass(1), yppasswd(1) is just a link to passwd(1), so NIS works with either command.


8.6.5 pw

pw(8) is a command line utility to create, remove, modify, and display users and groups. It functions as a front end to the system user and group files. pw(8) has a very powerful set of command line options that make it suitable for use in shell scripts, but new users may find it more complicated than the other commands presented here.


8.7 Limiting Users

If you have users, the ability to limit their system use may have come to mind. FreeBSD provides several ways an administrator can limit the amount of system resources an individual may use. These limits are divided into two sections: disk quotas, and other resource limits.

Disk quotas limit disk usage to users, and they provide a way to quickly check that usage without calculating it every time. Quotas are discussed in Section 12.12.

The other resource limits include ways to limit the amount of CPU, memory, and other resources a user may consume. These are defined using login classes and are discussed here.

Login classes are defined in /etc/login.conf. The precise semantics are beyond the scope of this section, but are described in detail in the login.conf(5) manual page. It is sufficient to say that each user is assigned to a login class (default by default), and that each login class has a set of login capabilities associated with it. A login capability is a name=value pair, where name is a well-known identifier and value is an arbitrary string processed accordingly depending on the name. Setting up login classes and capabilities is rather straight-forward and is also described in login.conf(5).

Resource limits are different from plain vanilla login capabilities in two ways. First, for every limit, there is a soft (current) and hard limit. A soft limit may be adjusted by the user or application, but may be no higher than the hard limit. The latter may be lowered by the user, but never raised. Second, most resource limits apply per process to a specific user, not the user as a whole. Note, however, that these differences are mandated by the specific handling of the limits, not by the implementation of the login capability framework (i.e., they are not really a special case of login capabilities).

And so, without further ado, below are the most commonly used resource limits (the rest, along with all the other login capabilities, may be found in login.conf(5)).

coredumpsize

The limit on the size of a core file generated by a program is, for obvious reasons, subordinate to other limits on disk usage (e.g., filesize, or disk quotas). Nevertheless, it is often used as a less-severe method of controlling disk space consumption: since users do not generate core files themselves, and often do not delete them, setting this may save them from running out of disk space should a large program (e.g., emacs) crash.

cputime

This is the maximum amount of CPU time a user's process may consume. Offending processes will be killed by the kernel.

Note: This is a limit on CPU time consumed, not percentage of the CPU as displayed in some fields by top(1) and ps(1). A limit on the latter is, at the time of this writing, not possible, and would be rather useless: a compiler--probably a legitimate task--can easily use almost 100% of a CPU for some time.



filesize

This is the maximum size of a file the user may possess. Unlike disk quotas, this limit is enforced on individual files, not the set of all files a user owns.

maxproc

This is the maximum number of processes a user may be running. This includes foreground and background processes alike. For obvious reasons, this may not be larger than the system limit specified by the kern.maxproc sysctl(8). Also note that setting this too small may hinder a user's productivity: it is often useful to be logged in multiple times or execute pipelines. Some tasks, such as compiling a large program, also spawn multiple processes (e.g., make(1), cc(1), and other intermediate preprocessors).

memorylocked

This is the maximum amount a memory a process may have requested to be locked into main memory (e.g., see mlock(2)). Some system-critical programs, such as amd(8), lock into main memory such that in the event of being swapped out, they do not contribute to a system's trashing in time of trouble.

memoryuse

This is the maximum amount of memory a process may consume at any given time. It includes both core memory and swap usage. This is not a catch-all limit for restricting memory consumption, but it is a good start.

openfiles

This is the maximum amount of files a process may have open. In FreeBSD, files are also used to represent sockets and IPC channels; thus, be careful not to set this too low. The system-wide limit for this is defined by the kern.maxfiles sysctl(8).

sbsize

This is the limit on the amount of network memory, and thus mbufs, a user may consume. This originated as a response to an old DoS attack by creating a lot of sockets, but can be generally used to limit network communications.

stacksize

This is the maximum size a process' stack may grow to. This alone is not sufficient to limit the amount of memory a program may use; consequently, it should be used in conjunction with other limits.

There are a few other things to remember when setting resource limits. Following are some general tips, suggestions, and miscellaneous comments.

  • Processes started at system startup by /etc/rc are assigned to the daemon login class.

  • Although the /etc/login.conf that comes with the system is a good source of reasonable values for most limits, only you, the administrator, can know what is appropriate for your system. Setting a limit too high may open your system up to abuse, while setting it too low may put a strain on productivity.

  • Users of the X Window System (X11) should probably be granted more resources than other users. X11 by itself takes a lot of resources, but it also encourages users to run more programs simultaneously.

  • Remember that many limits apply to individual processes, not the user as a whole. For example, setting openfiles to 50 means that each process the user runs may open up to 50 files. Thus, the gross amount of files a user may open is the value of openfiles multiplied by the value of maxproc. This also applies to memory consumption.

For further information on resource limits and login classes and capabilities in general, please consult the relevant manual pages: cap_mkdb(1), getrlimit(2), login.conf(5).


8.8 Personalizing Users

Localization is an environment set up by the system administrator or user to accommodate different languages, character sets, date and time standards, and so on. This is discussed in the localization chapter.


8.9 Groups

A group is simply a list of users. Groups are identified by their group name and GID (Group ID). In FreeBSD (and most other UNIX like systems), the two factors the kernel uses to decide whether a process is allowed to do something is its user ID and list of groups it belongs to. Unlike a user ID, a process has a list of groups associated with it. You may hear some things refer to the ``group ID'' of a user or process; most of the time, this just means the first group in the list.

The group name to group ID map is in /etc/group. This is a plain text file with four colon-delimited fields. The first field is the group name, the second is the encrypted password, the third the group ID, and the fourth the comma-delimited list of members. It can safely be edited by hand (assuming, of course, that you do not make any syntax errors!). For a more complete description of the syntax, see the group(5) manual page.

If you do not want to edit /etc/group manually, you can use the pw(8) command to add and edit groups. For example, to add a group called teamtwo and then confirm that it exists you can use:

Example 8-8. Adding a Group Using pw(8)

# pw groupadd teamtwo
# pw groupshow teamtwo
teamtwo:*:1100:

The number 1100 above is the group ID of the group teamtwo. Right now, teamtwo has no members, and is thus rather useless. Let's change that by inviting jru to the teamtwo group.

Example 8-9. Adding Somebody to a Group Using pw(8)

# pw groupmod teamtwo -M jru
# pw groupshow teamtwo
teamtwo:*:1100:jru

The argument to the -M option is a comma-delimited list of users who are members of the group. From the preceding sections, we know that the password file also contains a group for each user. The latter (the user) is automatically added to the group list by the system; the user will not show up as a member when using the groupshow command to pw(8), but will show up when the information is queried via id(1) or similar tool. In other words, pw(8) only manipulates the /etc/group file; it will never attempt to read additionally data from /etc/passwd.

Example 8-10. Using id(1) to Determine Group Membership

% id jru
uid=1001(jru) gid=1001(jru) groups=1001(jru), 1100(teamtwo)

As you can see, jru is a member of the groups jru and teamtwo.

For more information about pw(8), see its manual page, and for more information on the format of /etc/group, consult the group(5) manual page.


Chapter 9 Configuring the FreeBSD Kernel

Updated and restructured by Jim Mock. Originally contributed by Jake Hamby.

9.1 Synopsis

The kernel is the core of the FreeBSD operating system. It is responsible for managing memory, enforcing security controls, networking, disk access, and much more. While more and more of FreeBSD becomes dynamically configurable it is still occasionally necessary to reconfigure and recompile your kernel.

After reading this chapter, you will know:

  • Why you might need to build a custom kernel.

  • How to write a kernel configuration file, or alter an existing configuration file.

  • How to use the kernel configuration file to create and build a new kernel.

  • How to install the new kernel.

  • How to create any entries in /dev that may be required.

  • How to troubleshoot if things go wrong.


9.2 Why Build a Custom Kernel?

Traditionally, FreeBSD has had what is called a ``monolithic'' kernel. This means that the kernel was one large program, supported a fixed list of devices, and if you wanted to change the kernel's behavior then you had to compile a new kernel, and then reboot your computer with the new kernel.

Today, FreeBSD is rapidly moving to a model where much of the kernel's functionality is contained in modules which can be dynamically loaded and unloaded from the kernel as necessary. This allows the kernel to adapt to new hardware suddenly becoming available (such as PCMCIA cards in a laptop), or for new functionality to be brought into the kernel that was not necessary when the kernel was originally compiled. This is known as a modular kernel. Colloquially these are called KLDs.

Despite this, it is still necessary to carry out some static kernel configuration. In some cases this is because the functionality is so tied to the kernel that it can not be made dynamically loadable. In others it may simply be because no one has yet taken the time to write a dynamic loadable kernel module for that functionality yet.

Building a custom kernel is one of the most important rites of passage nearly every UNIX user must endure. This process, while time consuming, will provide many benefits to your FreeBSD system. Unlike the GENERIC kernel, which must support a wide range of hardware, a custom kernel only contains support for your PC's hardware. This has a number of benefits, such as:

  • Faster boot time. Since the kernel will only probe the hardware you have on your system, the time it takes your system to boot will decrease dramatically.

  • Less memory usage. A custom kernel often uses less memory than the GENERIC kernel, which is important because the kernel must always be present in real memory. For this reason, a custom kernel is especially useful on a system with a small amount of RAM.

  • Additional hardware support. A custom kernel allows you to add in support for devices such as sound cards, which are not present in the GENERIC kernel.


9.3 Building and Installing a Custom Kernel

First, let us take a quick tour of the kernel build directory. All directories mentioned will be relative to the main /usr/src/sys directory, which is also accessible through /sys. There are a number of subdirectories here representing different parts of the kernel, but the most important, for our purposes, are arch/conf, where you will edit your custom kernel configuration, and compile, which is the staging area where your kernel will be built. arch represents either i386, alpha, or pc98 (an alternative development branch of PC hardware, popular in Japan). Everything inside a particular architecture's directory deals with that architecture only; the rest of the code is common to all platforms to which FreeBSD could potentially be ported. Notice the logical organization of the directory structure, with each supported device, file system, and option in its own subdirectory. FreeBSD 5.X and up has support for sparc64, and a few other architectures under development.

Note: If there is not a /usr/src/sys directory on your system, then the kernel source has not been installed. The easiest way to do this is by running /stand/sysinstall as root, choosing Configure, then Distributions, then src, then sys. If you have an aversion to sysinstall and you have access to an ``official'' FreeBSD CDROM, then you can also install the source from the command line:

# mount /cdrom
# mkdir -p /usr/src/sys
# ln -s /usr/src/sys /sys
# cat /cdrom/src/ssys.[a-d]* | tar -xzvf -

Next, move to the arch/conf directory and copy the GENERIC configuration file to the name you want to give your kernel. For example:

# cd /usr/src/sys/i386/conf
# cp GENERIC MYKERNEL

Traditionally, this name is in all capital letters and, if you are maintaining multiple FreeBSD machines with different hardware, it is a good idea to name it after your machine's hostname. We will call it MYKERNEL for the purpose of this example.

Tip: Storing your kernel config file directly under /usr/src can be a bad idea. If you are experiencing problems it can be tempting to just delete /usr/src and start again. Five seconds after you do that you realize that you have deleted your custom kernel config file. Do not edit GENERIC directly, as it may get overwritten the next time you update your source tree, and your kernel modifications will be lost.

You might want to keep your kernel config file elsewhere, and then create a symbolic link to the file in the i386 directory.

For example:

# cd /usr/src/sys/i386/conf
# mkdir /root/kernels
# cp GENERIC /root/kernels/MYKERNEL   
# ln -s /root/kernels/MYKERNEL

Note: You must execute these and all of the following commands under the root account or you will get permission denied errors.

Now, edit MYKERNEL with your favorite text editor. If you are just starting out, the only editor available will probably be vi, which is too complex to explain here, but is covered well in many books in the bibliography. However, FreeBSD does offer an easier editor called ee which, if you are a beginner, should be your editor of choice. Feel free to change the comment lines at the top to reflect your configuration or the changes you have made to differentiate it from GENERIC.

If you have built a kernel under SunOS or some other BSD operating system, much of this file will be very familiar to you. If you are coming from some other operating system such as DOS, on the other hand, the GENERIC configuration file might seem overwhelming to you, so follow the descriptions in the Configuration File section slowly and carefully.

Note: Be sure to always check the file /usr/src/UPDATING, before you perform any update steps, in the case you sync your source tree with the latest sources of the FreeBSD project. In this file all important issues with updating FreeBSD are typed out. /usr/src/UPDATING always fits your version of the FreeBSD source, and is therefore more accurate for new information than the handbook.

You must now compile the source code for the kernel. There are two procedures you can use to do this, and the one you will use depends on why you are rebuilding the kernel, and the version of FreeBSD you are running.

  • If you have installed only the kernel source code, use procedure 1.

  • If you are running a FreeBSD version prior to 4.0, and you are not upgrading to FreeBSD 4.0 or higher using the make world procedure, use procedure 1.

  • If you are building a new kernel without updating the source code (perhaps just to add a new option, such as IPFIREWALL) you can use either procedure.

  • If you are rebuilding the kernel as part of a make world process, use procedure 2.

Procedure 1. Building a Kernel the ``Traditional'' Way

  1. Run config(8) to generate the kernel source code.

    # /usr/sbin/config MYKERNEL
    
  2. Change into the build directory. This is printed out after running the aforementioned command.

    # cd ../compile/MYKERNEL
    

    For FreeBSD version prior to 5.0, use instead:

    # cd ../../compile/MYKERNEL
    
  3. Compile the kernel.

    # make depend
    # make
    
  4. Install the new kernel.

    # make install
    

Procedure 2. Building a Kernel the ``New'' Way

  1. Change to the /usr/src directory.

    # cd /usr/src
    
  2. Compile the kernel.

    # make buildkernel KERNCONF=MYKERNEL
    
  3. Install the new kernel.

    # make installkernel KERNCONF=MYKERNEL
    

Note: In FreeBSD 4.2 and older you must replace KERNCONF= with KERNEL=. 4.2-STABLE that was fetched before Feb 2nd, 2001 does not recognize KERNCONF=.

If you have not upgraded your source tree in any way (you have not run CVSup, CTM, or used anoncvs), then you should use the config, make depend, make, make install sequence.

The new kernel will be copied to the root directory as /kernel and the old kernel will be moved to /kernel.old. Now, shutdown the system and reboot to use your new kernel. In case something goes wrong, there are some troubleshooting instructions at the end of this chapter. Be sure to read the section which explains how to recover in case your new kernel does not boot.

Note: As of FreeBSD 5.0, kernels are installed along with their modules in /boot/kernel, and old kernels will be backed up in /boot/kernel.old. Other files relating to the boot process, such as the boot loader(8) and configuration are also stored in /boot. Third party or custom modules may be placed in /boot/modules, although users should be aware that keeping modules in sync with the compiled kernel is very important. Modules not intended to run with the compiled kernel may result in instability or incorrectness.

Note: If you have added any new devices (such as sound cards) and you are running FreeBSD 4.X or previous versions, you may have to add some device nodes to your /dev directory before you can use them. For more information, take a look at Making Device Nodes section later on in this chapter.


9.4 The Configuration File

The general format of a configuration file is quite simple. Each line contains a keyword and one or more arguments. For simplicity, most lines only contain one argument. Anything following a # is considered a comment and ignored. The following sections describe each keyword, generally in the order they are listed in GENERIC, although some related keywords have been grouped together in a single section (such as Networking) even though they are actually scattered throughout the GENERIC file. An exhaustive list of options and more detailed explanations of the device lines is present in the LINT configuration file, located in the same directory as GENERIC. If you are in doubt as to the purpose or necessity of a line, check first in LINT.

Note: In FreeBSD 5.X and above the LINT is non-existent. See the NOTES file for architecture dependent options. Some options, mainly architecture independent ones, are stored in the /usr/src/sys/conf/NOTES file. It is advisable to review the options in here also.

The following is an example GENERIC kernel configuration file with various additional comments where needed for clarity. This example should match your copy in /usr/src/sys/i386/conf/GENERIC fairly closely. For details of all the possible kernel options, see /usr/src/sys/i386/conf/LINT.

#
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
#
#    http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ../../conf/NOTES and NOTES files. 
# If you are in doubt as to the purpose or necessity of a line, check first 
# in NOTES.
#
# $FreeBSD: src/sys/i386/conf/GENERIC,v 1.380 2003/03/29 13:36:41 mdodd Exp $

The following are the mandatory keywords required in every kernel you build:

machine        i386

This is the machine architecture. It must be either i386, pc98, sparc64, alpha, ia64, amd64, or powerpc.

cpu          I486_CPU
cpu          I586_CPU
cpu          I686_CPU

The above option specifies the type of CPU you have in your system. You may have multiple instances of the CPU line (i.e., you are not sure whether you should use I586_CPU or I686_CPU), however, for a custom kernel, it is best to specify only the CPU you have. If you are unsure of your CPU type, you can check the /var/run/dmesg.boot file to view your boot up messages.

Support for I386_CPU is still provided in the source of FreeBSD, but it is disabled by default in both -STABLE and -CURRENT. This means that to install FreeBSD with a 386-class cpu, you now have the following options:

  • Install an older FreeBSD release and rebuild from source as described in Section 9.3.

  • Build the userland and kernel on a newer machine and install on the 386 using the precompiled /usr/obj files (see Section 21.5 for details).

  • Roll your own release of FreeBSD which includes I386_CPU support in the kernels of the installation CD-ROM.

The first of these options is probably the easiest of all, but you will need a lot of disk space on a 386-class machine which may be difficult to find.

ident          GENERIC

This is the identification of the kernel. You should change this to whatever you named your kernel, i.e. MYKERNEL if you have followed the instructions of the previous examples. The value you put in the ident string will print when you boot up the kernel, so it is useful to give the new kernel a different name if you want to keep it separate from your usual kernel (i.e. you want to build an experimental kernel).

maxusers          n

The maxusers option sets the size of a number of important system tables. This number is supposed to be roughly equal to the number of simultaneous users you expect to have on your machine.

Starting with FreeBSD 4.5, the system will auto-tune this setting for you if you explicitly set it to 0[8]. In FreeBSD 5.X, maxusers will default to 0 if not specified. If you are using an version of FreeBSD earlier than 4.5, or you want to manage it yourself you will want to set maxusers to at least 4, especially if you are using the X Window System or compiling software. The reason is that the most important table set by maxusers is the maximum number of processes, which is set to 20 + 16 * maxusers, so if you set maxusers to 1, then you can only have 36 simultaneous processes, including the 18 or so that the system starts up at boot time, and the 15 or so you will probably create when you start the X Window System. Even a simple task like reading a manual page will start up nine processes to filter, decompress, and view it. Setting maxusers to 64 will allow you to have up to 1044 simultaneous processes, which should be enough for nearly all uses. If, however, you see the dreaded proc table full error when trying to start another program, or are running a server with a large number of simultaneous users (like ftp.FreeBSD.org), you can always increase the number and rebuild.

Note: maxusers does not limit the number of users which can log into your machine. It simply sets various table sizes to reasonable values considering the maximum number of users you will likely have on your system and how many processes each of them will be running. One keyword which does limit the number of simultaneous remote logins and X terminal windows is pseudo-device pty 16.

# Floating point support - do not disable.
device          npx0     at nexus? port IO_NPX irq 13

npx0 is the interface to the floating point math unit in FreeBSD, which is either the hardware co-processor or the software math emulator. This is not optional.

# Pseudo devices - the number indicates how many units to allocate.
pseudo-device   loop          # Network loopback

This is the generic loopback device for TCP/IP. If you telnet or FTP to localhost (a.k.a., 127.0.0.1) it will come back at you through this pseudo-device. This is mandatory.

Everything that follows is more or less optional. See the notes underneath or next to each option for more information.

#To statically compile in device wiring instead of /boot/device.hints
#hints          "GENERIC.hints"         #Default places to look for devices.

In FreeBSD 5.X and newer versions the device.hints(5) is used to configure options of the device drivers. The default location that loader(8) will check at boot time is /boot/device.hints. Using the hints option you can compile these hints statically into your kernel. Then there is no need to create a device.hints file in /boot.

#makeoptions     DEBUG=-g          #Build kernel with gdb(1) debug symbols

The normal build process of the FreeBSD does not include debugging information when building the kernel and strips most symbols after the resulting kernel is linked, to save some space at the install location. If you are going to do tests of kernels in the -CURRENT branch or develop changes of your own for the FreeBSD kernel, you might want to uncomment this line. It will enable the use of the -g option which enables debugging information when passed to gcc(1). The same can be accomplished by the config(8) -g option, if you are using the ``traditional'' way for building your kernels (See the Section 9.3 for more informations.).

options          MATH_EMULATE      #Support for x87 emulation

This line allows the kernel to simulate a math co-processor if your computer does not have one (386 or 486SX). If you have a 486DX, or a 386 or 486SX (with a separate 387 or 487 chip), or higher (Pentium, Pentium II, etc.), you can comment this line out.

Note: The normal math co-processor emulation routines that come with FreeBSD are not very accurate. If you do not have a math co-processor, and you need the best accuracy, it is recommended that you change this option to GPL_MATH_EMULATE to use the GNU math support, which is not included by default for licensing reasons.

In FreeBSD 5.X, math emulation is disabled by default, as older CPUs that do not have native floating point math support are far less common, and in many cases not supported by the GENERIC kernel without other additional options.

options          INET          #InterNETworking

Networking support. Leave this in, even if you do not plan to be connected to a network. Most programs require at least loopback networking (i.e., making network connections within your PC), so this is essentially mandatory.

options          INET6          #IPv6 communications protocols

This enables the IPv6 communication protocols.

options          FFS          #Berkeley Fast Filesystem
options          FFS_ROOT     #FFS usable as root device [keep this!]

This is the basic hard drive Filesystem. Leave it in if you boot from the hard disk.

Note: In FreeBSD 5.X, FFS_ROOT is no longer required.

options          UFS_ACL      #Support for access control lists

This option, present only in FreeBSD 5.X, enables kernel support for access control lists. This relies on the use of extended attributes and UFS2, and the feature is described in detail in the Section 10.13. ACLs are enabled by default, and should not be disabled in the kernel if they have been used previously on a file system, as this will remove the access control lists changing the way files are protected in unpredictable ways.

options          UFS_DIRHASH  #Improve performance on big directories

This option includes functionality to speed up disk operations on large directories, at the expense of using additional memory. You would normally keep this for a large server, or interactive workstation, and remove it if you are using FreeBSD on a smaller system where memory is at a premium and disk access speed is less important, such as a firewall.

options          SOFTUPDATES  #Enable FFS Soft Updates support

This option enables Soft Updates in the kernel, this will help speed up write access on the disks. Even when this functionality is provided by the kernel, it must be turned on for specific disks. Review the output from mount(8) to see if Soft Updates is enabled for your system disks. If you do not see the soft-updates option then you will need to activate it using the tunefs(8) (for existing filesystems) or newfs(8) (for new filesystems) commands.

options          MFS          #Memory Filesystem
options          MD_ROOT      #MD is a potential root device

This is the memory-mapped Filesystem. This is basically a RAM disk for fast storage of temporary files, useful if you have a lot of swap space that you want to take advantage of. A perfect place to mount an MFS partition is on the /tmp directory, since many programs store temporary data here. To mount an MFS RAM disk on /tmp, add the following line to /etc/fstab:

/dev/ad1s2b    /tmp mfs rw 0 0

Now you simply need to either reboot, or run the command mount /tmp.

Note: In FreeBSD 5.X, md(4)-backed UFS file systems are used for memory file systems rather than MFS. Information on configuring memory-backed file systems may be found in the manual pages for mdconfig(8) and mdmfs(8), and in Section 12.10. As a result, the MFS option is no longer supported.

options          NFS          #Network Filesystem
options          NFS_ROOT     #NFS usable as root device, NFS required

The network Filesystem. Unless you plan to mount partitions from a UNIX file server over TCP/IP, you can comment these out.

options          MSDOSFS      #MSDOS Filesystem

The MS-DOS Filesystem. Unless you plan to mount a DOS formatted hard drive partition at boot time, you can safely comment this out. It will be automatically loaded the first time you mount a DOS partition, as described above. Also, the excellent mtools software (in the ports collection) allows you to access DOS floppies without having to mount and unmount them (and does not require MSDOSFS at all).

options          CD9660       #ISO 9660 Filesystem
options          CD9660_ROOT  #CD-ROM usable as root, CD9660 required

The ISO 9660 Filesystem for CDROMs. Comment it out if you do not have a CDROM drive or only mount data CDs occasionally (since it will be dynamically loaded the first time you mount a data CD). Audio CDs do not need this Filesystem.

options          PROCFS       #Process filesystem

The process filesystem. This is a ``pretend'' filesystem mounted on /proc which allows programs like ps(1) to give you more information on what processes are running. In FreeBSD 5.X, use of PROCFS is not required under most circumstances, as most debugging and monitoring tools have been adapted to run without PROCFS. In addition, 5.X-CURRENT kernels making use of PROCFS must now also include support for PSEUDOFS:

options          PSEUDOFS     #Pseudo-filesystem framework

PSEUDOFS is not available in FreeBSD 4.X. Unlike in FreeBSD 4.X, new installations of FreeBSD 5.X will not mount the process file system by default.

options          COMPAT_43    #Compatible with BSD 4.3 [KEEP THIS!]

Compatibility with 4.3BSD. Leave this in; some programs will act strangely if you comment this out.

options          COMPAT_FREEBSD4     #Compatible with FreeBSD4

This option is required on FreeBSD 5.X i386 and Alpha systems to support applications compiled on older versions of FreeBSD that use older system call interfaces. It is recommended that this option be used on all i386 and Alpha systems that may run older applications; platforms that gained support only in 5.X, such as ia64 and Sparc64®, do not require this option.

options          SCSI_DELAY=15000    #Delay (in ms) before probing SCSI

This causes the kernel to pause for 15 seconds before probing each SCSI device in your system. If you only have IDE hard drives, you can ignore this, otherwise you will probably want to lower this number, perhaps to 5 seconds, to speed up booting. Of course, if you do this, and FreeBSD has trouble recognizing your SCSI devices, you will have to raise it back up.

options          UCONSOLE            #Allow users to grab the console

Allow users to grab the console, which is useful for X users. For example, you can create a console xterm by typing xterm -C, which will display any write(1), talk(1), and any other messages you receive, as well as any console messages sent by the kernel.

Note: In FreeBSD 5.X, UCONSOLE is no longer required.

options          USERCONFIG          #boot -c editor

This option allows you to boot the configuration editor from the boot menu.

options          VISUAL_USERCONFIG   #visual boot -c editor

This option allows you to boot the visual configuration editor from the boot menu.

Note: From FreeBSD versions 5.0 and later, the USERCONFIG options has been deprecated in favor of the new device.hints(5) method. For more information on device.hints(5) please visit Section 7.5.

options          KTRACE              #ktrace(1) support

This enables kernel process tracing, which is useful in debugging.

options          SYSVSHM             #SYSV-style shared memory

This option provides for System V shared memory. The most common use of this is the XSHM extension in X, which many graphics-intensive programs will automatically take advantage of for extra speed. If you use X, you will definitely want to include this.

options          SYSVSEM             #SYSV-style semaphores

Support for System V semaphores. Less commonly used but only adds a few hundred bytes to the kernel.

options          SYSVMSG             #SYSV-style message queues

Support for System V messages. Again, only adds a few hundred bytes to the kernel.

Note: The ipcs(1) command will list any processes using each of these System V facilities.

options    P1003_1B        #Posix P1003_1B real-time extensions
options     _KPOSIX_PRIORITY_SCHEDULING

Real-time extensions added in the 1993 POSIX®. Certain applications in the ports collection use these (such as StarOffice).

Note: In FreeBSD 5.X, all of this functionality is now provided by the _KPOSIX_PRIORITY_SCHEDULING option, and P1003_1B is no longer required.

options        ICMP_BANDLIM        #Rate limit bad replies

This option enables ICMP error response bandwidth limiting. You typically want this option as it will help protect the machine from denial of service packet attacks.

Note: In FreeBSD 5.X, this feature is enabled by default and the ICMP_BANDLIM option is not required.

# To make an SMP kernel, the next two are needed
#options        SMP                     # Symmetric MultiProcessor Kernel
#options        APIC_IO                 # Symmetric (APIC) I/O

The above are both required for SMP support.

device          isa

All PCs supported by FreeBSD have one of these. If you have an IBM PS/2 (Micro Channel Architecture), FreeBSD provides some limited support at this time. For more information about the MCA support, see /usr/src/sys/i386/conf/LINT.

device          eisa

Include this if you have an EISA motherboard. This enables auto-detection and configuration support for all devices on the EISA bus.

device          pci

Include this if you have a PCI motherboard. This enables auto-detection of PCI cards and gatewaying from the PCI to ISA bus.

device          agp

Include this if you have an AGP card in the system. This will enable support for AGP, and AGP GART for boards which have these features.

# Floppy drives
device          fdc0        at isa? port IO_FD1 irq 6 drq 2
device          fd0         at fdc0 drive 0
device          fd1         at fdc0 drive 1

This is the floppy drive controller. fd0 is the A: floppy drive, and fd1 is the B: drive.

device          ata

This driver supports all ATA and ATAPI devices. You only need one device ata line for the kernel to detect all PCI ATA/ATAPI devices on modern machines.

device          atadisk                 # ATA disk drives

This is needed along with device ata for ATA disk drives.


device          atapicd                 # ATAPI CDROM drives

This is needed along with device ata for ATAPI CDROM drives.

device          atapifd                 # ATAPI floppy drives

This is needed along with device ata for ATAPI floppy drives.

device          atapist                 # ATAPI tape drives

This is needed along with device ata for ATAPI tape drives.

options         ATA_STATIC_ID           #Static device numbering

This makes the controller number static (like the old driver) or else the device numbers are dynamically allocated.

# ATA and ATAPI devices
device          ata0        at isa? port IO_WD1 irq 14
device          ata1        at isa? port IO_WD2 irq 15

Use the above for older, non-PCI systems.

# SCSI Controllers
device          ahb        # EISA AHA1742 family
device          ahc        # AHA2940 and onboard AIC7xxx devices
device          amd        # AMD 53C974 (Teckram DC-390(T))
device          dpt        # DPT Smartcache - See LINT for options!
device          isp        # Qlogic family
device          ncr        # NCR/Symbios Logic
device          sym        # NCR/Symbios Logic (newer chipsets)

device          adv0       at isa?
device          adw
device          bt0        at isa?
device          aha0       at isa?
device          aic0       at isa?

SCSI controllers. Comment out any you do not have in your system. If you have an IDE only system, you can remove these altogether.

# SCSI peripherals
device          scbus      # SCSI bus (required)
device          da         # Direct Access (disks)
device          sa         # Sequential Access (tape etc)
device          cd         # CD
device          pass       # Passthrough device (direct SCSI
access)

SCSI peripherals. Again, comment out any you do not have, or if you have only IDE hardware, you can remove them completely.

# RAID controllers
device          ida        # Compaq Smart RAID
device          amr        # AMI MegaRAID
device          mlx        # Mylex DAC960 family

Supported RAID controllers. If you do not have any of these, you can comment them out or remove them.

# atkbdc0 controls both the keyboard and the PS/2 mouse
device          atkbdc0    at isa? port IO_KBD

The keyboard controller (atkbdc) provides I/O services for the AT keyboard and PS/2 style pointing devices. This controller is required by the keyboard driver (atkbd) and the PS/2 pointing device driver (psm).

device          atkbd0     at atkbdc? irq 1

The atkbd driver, together with atkbdc controller, provides access to the AT 84 keyboard or the AT enhanced keyboard which is connected to the AT keyboard controller.

device          psm0       at atkbdc? irq 12

Use this device if your mouse plugs into the PS/2 mouse port.

device          vga0        at isa?

The video card driver.

# splash screen/screen saver
pseudo-device          splash

Splash screen at start up! Screen savers require this too.

# syscons is the default console driver, resembling an SCO console
device          sc0          at isa?

sc0 is the default console driver, which resembles a SCO console. Since most full-screen programs access the console through a terminal database library like termcap, it should not matter whether you use this or vt0, the VT220 compatible console driver. When you log in, set your TERM variable to scoansi if full-screen programs have trouble running under this console.

# Enable this and PCVT_FREEBSD for pcvt vt220 compatible console driver
#device          vt0     at isa?
#options         XSERVER          # support for X server on a vt console
#options         FAT_CURSOR       # start with block cursor
# If you have a ThinkPAD, uncomment this along with the rest of the PCVT lines
#options         PCVT_SCANSET=2   # IBM keyboards are non-std

This is a VT220-compatible console driver, backward compatible to VT100/102. It works well on some laptops which have hardware incompatibilities with sc0. Also set your TERM variable to vt100 or vt220 when you log in. This driver might also prove useful when connecting to a large number of different machines over the network, where termcap or terminfo entries for the sc0 device are often not available -- vt100 should be available on virtually any platform.

# Power management support (see LINT for more options)
device          apm0     at nexus? disable flags 0x20  # Advanced Power Management

Advanced Power Management support. Useful for laptops.

# PCCARD (PCMCIA) support
device          card
device          pcic0    at isa? irq 10 port 0x3e0 iomem 0xd0000
device          pcic1    at isa? irq 11 port 0x3e2 iomem 0xd4000 disable

PCMCIA support. You want this if you are using a laptop.

# Serial (COM) ports
device          sio0     at isa? port IO_COM1 flags 0x10 irq 4
device          sio1     at isa? port IO_COM2 irq 3
device          sio2     at isa? disable port IO_COM3 irq 5
device          sio3     at isa? disable port IO_COM4 irq 9

These are the four serial ports referred to as COM1 through COM4 in the MS-DOS/Windows world.

Note: If you have an internal modem on COM4 and a serial port at COM2, you will have to change the IRQ of the modem to 2 (for obscure technical reasons, IRQ2 = IRQ 9) in order to access it from FreeBSD. If you have a multiport serial card, check the manual page for sio(4) for more information on the proper values for these lines. Some video cards (notably those based on S3 chips) use IO addresses in the form of 0x*2e8, and since many cheap serial cards do not fully decode the 16-bit IO address space, they clash with these cards making the COM4 port practically unavailable.

Each serial port is required to have a unique IRQ (unless you are using one of the multiport cards where shared interrupts are supported), so the default IRQs for COM3 and COM4 cannot be used.

# Parallel port
device          ppc0    at isa? irq 7

This is the ISA-bus parallel port interface.

device          ppbus      # Parallel port bus (required)

Provides support for the parallel port bus.

device          lpt        # Printer

Support for parallel port printers.

Note: All three of the above are required to enable parallel printer support.

device          plip       # TCP/IP over parallel

This is the driver for the parallel network interface.

device          ppi        # Parallel port interface device

The general-purpose I/O (``geek port'') + IEEE1284 I/O.

#device         vpo        # Requires scbus and da

This is for an Iomega Zip drive. It requires scbus and da support. Best performance is achieved with ports in EPP 1.9 mode.

# PCI Ethernet NICs.
device          de         # DEC/Intel DC21x4x (``Tulip'')
device          fxp        # Intel EtherExpress PRO/100B (82557, 82558)
device          tx         # SMC 9432TX (83c170 ``EPIC'')
device          vx         # 3Com 3c590, 3c595 (``Vortex'')
device          wx         # Intel Gigabit Ethernet Card (``Wiseman'')

Various PCI network card drivers. Comment out or remove any of these not present in your system.

# PCI Ethernet NICs that use the common MII bus controller code.
device          miibus     # MII bus support

MII bus support is required for some PCI 10/100 Ethernet NICs, namely those which use MII-compliant transceivers or implement transceiver control interfaces that operate like an MII. Adding device miibus to the kernel config pulls in support for the generic miibus API and all of the PHY drivers, including a generic one for PHYs that are not specifically handled by an individual driver.

device          dc         # DEC/Intel 21143 and various workalikes
device          rl         # RealTek 8129/8139
device          sf         # Adaptec AIC-6915 (``Starfire'')
device          sis        # Silicon Integrated Systems SiS 900/SiS 7016
device          ste        # Sundance ST201 (D-Link DFE-550TX)
device          tl         # Texas Instruments ThunderLAN
device          vr         # VIA Rhine, Rhine II
device          wb         # Winbond W89C840F
device          xl         # 3Com 3c90x (``Boomerang'', ``Cyclone'')

Drivers that use the MII bus controller code.

# ISA Ethernet NICs.
device          ed0    at isa? port 0x280 irq 10 iomem 0xd8000
device          ex
device          ep
# WaveLAN/IEEE 802.11 wireless NICs. Note: the WaveLAN/IEEE really
# exists only as a PCMCIA device, so there is no ISA attachment needed
# and resources will always be dynamically assigned by the pccard code.
device          wi
# Aironet 4500/4800 802.11 wireless NICs. Note: the declaration below will
# work for PCMCIA and PCI cards, as well as ISA cards set to ISA PnP
# mode (the factory default). If you set the switches on your ISA
# card for a manually chosen I/O address and IRQ, you must specify
# those parameters here.
device          an
# The probe order of these is presently determined by i386/isa/isa_compat.c.
device          ie0    at isa? port 0x300 irq 10 iomem 0xd0000
device          fe0    at isa? port 0x300
device          le0    at isa? port 0x300 irq 5 iomem 0xd0000
device          lnc0   at isa? port 0x280 irq 10 drq 0
device          cs0    at isa? port 0x300
device          sn0    at isa? port 0x300 irq 10
# requires PCCARD (PCMCIA) support to be activated
#device         xe0    at isa?

ISA Ethernet drivers. See /usr/src/sys/i386/conf/LINT for which cards are supported by which driver.

pseudo-device   ether         # Ethernet support

ether is only needed if you have an Ethernet card. It includes generic Ethernet protocol code.

pseudo-device   sl      1     # Kernel SLIP

sl is for SLIP support. This has been almost entirely supplanted by PPP, which is easier to set up, better suited for modem-to-modem connection, and more powerful. The number after sl specifies how many simultaneous SLIP sessions to support.

pseudo-device   ppp     1     # Kernel PPP

This is for kernel PPP support for dial-up connections. There is also a version of PPP implemented as a userland application that uses tun and offers more flexibility and features such as demand dialing. The number after ppp specifies how many simultaneous PPP connections to support.

pseudo-device   tun           # Packet tunnel.

This is used by the userland PPP software. A number after tun specifies the number of simultaneous PPP sessions to support. See the PPP section of this book for more information.


pseudo-device   pty           # Pseudo-ttys (telnet etc)

This is a ``pseudo-terminal'' or simulated login port. It is used by incoming telnet and rlogin sessions, xterm, and some other applications such as Emacs. A number after pty indicates the number of ptys to create. If you need more than the default of 16 simultaneous xterm windows and/or remote logins, be sure to increase this number accordingly, up to a maximum of 256.

pseudo-device   md            # Memory ``disks''

Memory disk pseudo-devices.

pseudo-device   gif

or

pseudo-device   gif     4     # IPv6 and IPv4 tunneling

This implements IPv6 over IPv4 tunneling, IPv4 over IPv6 tunneling, IPv4 over IPv4 tunneling, and IPv6 over IPv6 tunneling. Beginning with FreeBSD 4.4 the gif device is ``auto-cloning'', and you should use the first example (without the number after gif). Earlier versions of FreeBSD require the number.

pseudo-device   faith   1     # IPv6-to-IPv4 relaying (translation)

This pseudo-device captures packets that are sent to it and diverts them to the IPv4/IPv6 translation daemon.

# The `bpf' pseudo-device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
pseudo-device   bpf           # Berkeley packet filter

This is the Berkeley Packet Filter. This pseudo-device allows network interfaces to be placed in promiscuous mode, capturing every packet on a broadcast network (e.g., an Ethernet). These packets can be captured to disk and or examined with the tcpdump(1) program.

Note: The bpf pseudo-device is also used by dhclient(8) to obtain the IP address of the default router (gateway) and so on. If you use DHCP, leave this uncommented.

# USB support
#device         uhci          # UHCI PCI->USB interface
#device         ohci          # OHCI PCI->USB interface
#device         usb           # USB Bus (required)
#device         ugen          # Generic
#device         uhid          # ``Human Interface Devices''
#device         ukbd          # Keyboard
#device         ulpt          # Printer
#device         umass         # Disks/Mass storage - Requires scbus and da
#device         ums           # Mouse
# USB Ethernet, requires mii
#device         aue           # ADMtek USB ethernet
#device         cue           # CATC USB ethernet
#device         kue           # Kawasaki LSI USB ethernet

Support for various USB devices.

For more information and additional devices supported by FreeBSD, see /usr/src/sys/i386/conf/LINT.


9.4.1 Large Memory Configurations (PAE)

Large memory configuration machines require access to more than the 4 gigabyte limit on User+Kernel Virtual Address (KVA) space. Due to this limitation, Intel added support for 36-bit physical address space access in the Pentium Pro and later line of CPUs.

The Physical Address Extension (PAE) capability of the Intel Pentium Pro and later CPUs allows memory configurations of up to 64 gigabytes. FreeBSD provides support for this capability via the PAE kernel configuration option, available in the 4.X series of FreeBSD beginning with 4.9-RELEASE and in the 5.X series of FreeBSD beginning with 5.1-RELEASE. Due to the limitations of the Intel memory architecture, no distinction is made for memory above or below 4 gigabytes. Memory allocated above 4 gigabytes is simply added to the pool of available memory.

To enable PAE support in the kernel, simply add the following line to your kernel configuration file:

options            PAE

Note: The PAE support in FreeBSD is only available for Intel IA-32 processors. It should also be noted, that the PAE support in FreeBSD has not received wide testing, and should be considered beta quality compared to other stable features of FreeBSD.

PAE support in FreeBSD has a few limitations:

  • A process is not able to access more than 4 gigabytes of VM space.

  • KLD modules cannot be loaded into a PAE enabled kernel, due to the differences in the build framework of a module and the kernel.

  • Device drivers that do not use the bus_dma(9) interface will cause data corruption in a PAE enabled kernel and are not recommended for use. For this reason, the PAE kernel configuration file is provided in FreeBSD 5.X, which excludes all drivers not known to work in a PAE enabled kernel.

  • Some system tunables determine memory resource usage by the amount of available physical memory. Such tunables can unnecessarily over-allocate due to the large memory nature of a PAE system. One such example is the kern.maxvnodes sysctl, which controls the maximum number of vnodes allowed in the kernel. It is advised to adjust this and other such tunables to a reasonable value.

  • It might be necessary to increase the kernel virtual address (KVA) space or to reduce the amount of specific kernel resource that is heavily used (see above) in order to avoid KVA exhaustion. The KVA_PAGES kernel option can be used for increasing the KVA space.

For performance and stability concerns, it is advised to consult the tuning(7) manual page. The pae(4) manual page contains up-to-date information on FreeBSD's PAE support.


9.5 Making Device Nodes

Note: If you are running FreeBSD 5.0 or later you can safely skip this section. These versions use devfs(5) to allocate device nodes transparently for the user.

Almost every device in the kernel has a corresponding ``node'' entry in the /dev directory. These nodes look like regular files, but are actually special entries into the kernel which programs use to access the device. The shell script /dev/MAKEDEV, which is executed when you first install the operating system, creates nearly all of the device nodes supported. However, it does not create all of them, so when you add support for a new device, it pays to make sure that the appropriate entries are in this directory, and if not, add them. Here is a simple example:

Suppose you add the IDE CD-ROM support to the kernel. The line to add is:

device acd0

This means that you should look for some entries that start with acd0 in the /dev directory, possibly followed by a letter, such as c, or preceded by the letter r, which means a ``raw'' device. It turns out that those files are not there, so you must change to the /dev directory and type:

# sh MAKEDEV acd0

When this script finishes, you will find that there are now acd0c and racd0c entries in /dev so you know that it executed correctly.

For sound cards, the following command creates the appropriate entries:

# sh MAKEDEV snd0

Note: When creating device nodes for devices such as sound cards, if other people have access to your machine, it may be desirable to protect the devices from outside access by adding them to the /etc/fbtab file. See fbtab(5) for more information.

Follow this simple procedure for any other non-GENERIC devices which do not have entries.

Note: All SCSI controllers use the same set of /dev entries, so you do not need to create these. Also, network cards and SLIP/PPP pseudo-devices do not have entries in /dev at all, so you do not have to worry about these either.


9.6 If Something Goes Wrong

There are five categories of trouble that can occur when building a custom kernel. They are:

config fails:

If the config(8) command fails when you give it your kernel description, you have probably made a simple error somewhere. Fortunately, config(8) will print the line number that it had trouble with, so you can quickly skip to it with vi. For example, if you see:

config: line 17: syntax error

You can skip to the problem in vi by typing 17G in command mode. Make sure the keyword is typed correctly, by comparing it to the GENERIC kernel or another reference.

make fails:

If the make command fails, it usually signals an error in your kernel description, but not severe enough for config(8) to catch it. Again, look over your configuration, and if you still cannot resolve the problem, send mail to the FreeBSD general questions mailing list with your kernel configuration, and it should be diagnosed very quickly.

Installing the new kernel fails:

If the kernel compiled fine, but failed to install (the make install or make installkernel command failed), the first thing to check is if your system is running at securelevel 1 or higher (see init(8)). The kernel installation tries to remove the immutable flag from your kernel and set the immutable flag on the new one. Since securelevel 1 or higher prevents unsetting the immutable flag for any files on the system, the kernel installation needs to be performed at securelevel 0 or lower.

The kernel does not boot:

If your new kernel does not boot, or fails to recognize your devices, do not panic! Fortunately, FreeBSD has an excellent mechanism for recovering from incompatible kernels. Simply choose the kernel you want to boot from at the FreeBSD boot loader. You can access this when the system counts down from 10. Hit any key except for the Enter key, type unload and then type boot kernel.old, or the filename of any other kernel that will boot properly. When reconfiguring a kernel, it is always a good idea to keep a kernel that is known to work on hand.

After booting with a good kernel you can check over your configuration file and try to build it again. One helpful resource is the /var/log/messages file which records, among other things, all of the kernel messages from every successful boot. Also, the dmesg(8) command will print the kernel messages from the current boot.

Note: If you are having trouble building a kernel, make sure to keep a GENERIC, or some other kernel that is known to work on hand as a different name that will not get erased on the next build. You cannot rely on kernel.old because when installing a new kernel, kernel.old is overwritten with the last installed kernel which may be non-functional. Also, as soon as possible, move the working kernel to the proper kernel location or commands such as ps(1) will not work properly. The proper command to ``unlock'' the kernel file that make installs (in order to move another kernel back permanently) is:

# chflags noschg /kernel

If you find you cannot do this, you are probably running at a securelevel(8) greater than zero. Edit kern_securelevel in /etc/rc.conf and set it to -1, then reboot. You can change it back to its previous setting when you are happy with your new kernel.

And, if you want to ``lock'' your new kernel into place, or any file for that matter, so that it cannot be moved or tampered with:

# chflags schg /kernel

In FreeBSD 5.X, kernels are not installed with the system immutable flag, so this is unlikely to be the source of the problem you are experiencing.

The kernel works, but ps(1) does not work any more:

If you have installed a different version of the kernel from the one that the system utilities have been built with, for example, a 4.X kernel on a 3.X system, many system-status commands like ps(1) and vmstat(8) will not work any more. You must recompile the libkvm library as well as these utilities. This is one reason it is not normally a good idea to use a different version of the kernel from the rest of the operating system.


Chapter 10 Security

Much of this chapter has been taken from the security(7) manual page by Matthew Dillon.

10.1 Synopsis

This chapter will provide a basic introduction to system security concepts, some general good rules of thumb, and some advanced topics under FreeBSD. A lot of the topics covered here can be applied to system and Internet security in general as well. The Internet is no longer a ``friendly'' place in which everyone wants to be your kind neighbor. Securing your system is imperative to protect your data, intellectual property, time, and much more from the hands of hackers and the like.

FreeBSD provides an array of utilities and mechanisms to ensure the integrity and security of your system and network.

After reading this chapter, you will know:

  • Basic system security concepts, in respect to FreeBSD.

  • About the various crypt mechanisms available in FreeBSD, such as DES and MD5.

  • How to set up one-time password authentication.

  • How to set up KerberosIV on FreeBSD releases prior to 5.0.

  • How to set up Kerberos5 on post FreeBSD 5.0 releases.

  • How to create firewalls using IPFW.

  • How to configure IPsec and create a VPN between FreeBSD/Windows machines.

  • How to configure and use OpenSSH, FreeBSD's SSH implementation.

  • How to configure and load access control extension modules using the TrustedBSD MAC Framework.

  • What file system ACLs are and how to use them.

  • How to utililize the FreeBSD security advisories publications.

Before reading this chapter, you should:

  • Understand basic FreeBSD and Internet concepts.


10.2 Introduction

Security is a function that begins and ends with the system administrator. While all BSD UNIX multi-user systems have some inherent security, the job of building and maintaining additional security mechanisms to keep those users ``honest'' is probably one of the single largest undertakings of the sysadmin. Machines are only as secure as you make them, and security concerns are ever competing with the human necessity for convenience. UNIX systems, in general, are capable of running a huge number of simultaneous processes and many of these processes operate as servers - meaning that external entities can connect and talk to them. As yesterday's mini-computers and mainframes become today's desktops, and as computers become networked and internetworked, security becomes an even bigger issue.

Security is best implemented through a layered ``onion'' approach. In a nutshell, what you want to do is to create as many layers of security as are convenient and then carefully monitor the system for intrusions. You do not want to overbuild your security or you will interfere with the detection side, and detection is one of the single most important aspects of any security mechanism. For example, it makes little sense to set the schg flags (see chflags(1)) on every system binary because while this may temporarily protect the binaries, it prevents an attacker who has broken in from making an easily detectable change that may result in your security mechanisms not detecting the attacker at all.

System security also pertains to dealing with various forms of attack, including attacks that attempt to crash, or otherwise make a system unusable, but do not attempt to compromise the root account (``break root''). Security concerns can be split up into several categories:

  1. Denial of service attacks.

  2. User account compromises.

  3. Root compromise through accessible servers.

  4. Root compromise via user accounts.

  5. Backdoor creation.

A denial of service attack is an action that deprives the machine of needed resources. Typically, DoS attacks are brute-force mechanisms that attempt to crash or otherwise make a machine unusable by overwhelming its servers or network stack. Some DoS attacks try to take advantage of bugs in the networking stack to crash a machine with a single packet. The latter can only be fixed by applying a bug fix to the kernel. Attacks on servers can often be fixed by properly specifying options to limit the load the servers incur on the system under adverse conditions. Brute-force network attacks are harder to deal with. A spoofed-packet attack, for example, is nearly impossible to stop, short of cutting your system off from the Internet. It may not be able to take your machine down, but it can saturate your Internet connection.

A user account compromise is even more common than a DoS attack. Many sysadmins still run standard telnetd, rlogind, rshd, and ftpd servers on their machines. These servers, by default, do not operate over encrypted connections. The result is that if you have any moderate-sized user base, one or more of your users logging into your system from a remote location (which is the most common and convenient way to login to a system) will have his or her password sniffed. The attentive system admin will analyze his remote access logs looking for suspicious source addresses even for successful logins.

One must always assume that once an attacker has access to a user account, the attacker can break root. However, the reality is that in a well secured and maintained system, access to a user account does not necessarily give the attacker access to root. The distinction is important because without access to root the attacker cannot generally hide his tracks and may, at best, be able to do nothing more than mess with the user's files, or crash the machine. User account compromises are very common because users tend not to take the precautions that sysadmins take.

System administrators must keep in mind that there are potentially many ways to break root on a machine. The attacker may know the root password, the attacker may find a bug in a root-run server and be able to break root over a network connection to that server, or the attacker may know of a bug in a suid-root program that allows the attacker to break root once he has broken into a user's account. If an attacker has found a way to break root on a machine, the attacker may not have a need to install a backdoor. Many of the root holes found and closed to date involve a considerable amount of work by the attacker to cleanup after himself, so most attackers install backdoors. A backdoor provides the attacker with a way to easily regain root access to the system, but it also gives the smart system administrator a convenient way to detect the intrusion. Making it impossible for an attacker to install a backdoor may actually be detrimental to your security, because it will not close off the hole the attacker found to break in the first place.

Security remedies should always be implemented with a multi-layered ``onion peel'' approach and can be categorized as follows:

  1. Securing root and staff accounts.

  2. Securing root - root-run servers and suid/sgid binaries.

  3. Securing user accounts.

  4. Securing the password file.

  5. Securing the kernel core, raw devices, and filesystems.

  6. Quick detection of inappropriate changes made to the system.

  7. Paranoia.

The next section of this chapter will cover the above bullet items in greater depth.


10.3 Securing FreeBSD

Command vs. Protocol: Throughout this document, we will use bold text to refer to a command or application. This is used for instances such as ssh, since it is a protocol as well as command.

The sections that follow will cover the methods of securing your FreeBSD system that were mentioned in the last section of this chapter.


10.3.1 Securing the root Account and Staff Accounts

First off, do not bother securing staff accounts if you have not secured the root account. Most systems have a password assigned to the root account. The first thing you do is assume that the password is always compromised. This does not mean that you should remove the password. The password is almost always necessary for console access to the machine. What it does mean is that you should not make it possible to use the password outside of the console or possibly even with the su(1) command. For example, make sure that your pty's are specified as being insecure in the /etc/ttys file so that direct root logins via telnet or rlogin are disallowed. If using other login services such as sshd, make sure that direct root logins are disabled there as well. You can do this by editing your /etc/ssh/sshd_config file, and making sure that PermitRootLogin is set to NO. Consider every access method - services such as FTP often fall through the cracks. Direct root logins should only be allowed via the system console.

Of course, as a sysadmin you have to be able to get to root, so we open up a few holes. But we make sure these holes require additional password verification to operate. One way to make root accessible is to add appropriate staff accounts to the wheel group (in /etc/group). The staff members placed in the wheel group are allowed to su to root. You should never give staff members native wheel access by putting them in the wheel group in their password entry. Staff accounts should be placed in a staff group, and then added to the wheel group via the /etc/group file. Only those staff members who actually need to have root access should be placed in the wheel group. It is also possible, when using an authentication method such as Kerberos, to use Kerberos' .k5login file in the root account to allow a ksu(1) to root without having to place anyone at all in the wheel group. This may be the better solution since the wheel mechanism still allows an intruder to break root if the intruder has gotten hold of your password file and can break into a staff account. While having the wheel mechanism is better than having nothing at all, it is not necessarily the safest option.

An indirect way to secure staff accounts, and ultimately root access is to use an alternative login access method and do what is known as ``starring'' out the encrypted password for the staff accounts. Using the vipw(8) command, one can replace each instance of an encrypted password with a single ``*'' character. This command will update the /etc/master.passwd file and user/password database to disable password-authenticated logins.

A staff account entry such as:

foobar:R9DT/Fa1/LV9U:1000:1000::0:0:Foo Bar:/home/foobar:/usr/local/bin/tcsh

Should be changed to this:

foobar:*:1000:1000::0:0:Foo Bar:/home/foobar:/usr/local/bin/tcsh

This change will prevent normal logins from occurring, since the encrypted password will never match ``*''. With this done, staff members must use another mechanism to authenticate themselves such as kerberos(1) or ssh(1) using a public/private key pair. When using something like Kerberos, one generally must secure the machines which run the Kerberos servers and your desktop workstation. When using a public/private key pair with ssh, one must generally secure the machine used to login from (typically one's workstation). An additional layer of protection can be added to the key pair by password protecting the key pair when creating it with ssh-keygen(1). Being able to ``star'' out the passwords for staff accounts also guarantees that staff members can only login through secure access methods that you have set up. This forces all staff members to use secure, encrypted connections for all of their sessions, which closes an important hole used by many intruders: sniffing the network from an unrelated, less secure machine.

The more indirect security mechanisms also assume that you are logging in from a more restrictive server to a less restrictive server. For example, if your main box is running all sorts of servers, your workstation should not be running any. In order for your workstation to be reasonably secure you should run as few servers as possible, up to and including no servers at all, and you should run a password-protected screen blanker. Of course, given physical access to a workstation an attacker can break any sort of security you put on it. This is definitely a problem that you should consider, but you should also consider the fact that the vast majority of break-ins occur remotely, over a network, from people who do not have physical access to your workstation or servers.

Using something like Kerberos also gives you the ability to disable or change the password for a staff account in one place, and have it immediately effect all the machines on which the staff member may have an account. If a staff member's account gets compromised, the ability to instantly change his password on all machines should not be underrated. With discrete passwords, changing a password on N machines can be a mess. You can also impose re-passwording restrictions with Kerberos: not only can a Kerberos ticket be made to timeout after a while, but the Kerberos system can require that the user choose a new password after a certain period of time (say, once a month).


10.3.2 Securing Root-run Servers and SUID/SGID Binaries

The prudent sysadmin only runs the servers he needs to, no more, no less. Be aware that third party servers are often the most bug-prone. For example, running an old version of imapd or popper is like giving a universal root ticket out to the entire world. Never run a server that you have not checked out carefully. Many servers do not need to be run as root. For example, the ntalk, comsat, and finger daemons can be run in special user sandboxes. A sandbox is not perfect, unless you go through a large amount of trouble, but the onion approach to security still stands: If someone is able to break in through a server running in a sandbox, they still have to break out of the sandbox. The more layers the attacker must break through, the lower the likelihood of his success. Root holes have historically been found in virtually every server ever run as root, including basic system servers. If you are running a machine through which people only login via sshd and never login via telnetd or rshd or rlogind, then turn off those services!

FreeBSD now defaults to running ntalkd, comsat, and finger in a sandbox. Another program which may be a candidate for running in a sandbox is named(8). /etc/defaults/rc.conf includes the arguments necessary to run named in a sandbox in a commented-out form. Depending on whether you are installing a new system or upgrading an existing system, the special user accounts used by these sandboxes may not be installed. The prudent sysadmin would research and implement sandboxes for servers whenever possible.

There are a number of other servers that typically do not run in sandboxes: sendmail, popper, imapd, ftpd, and others. There are alternatives to some of these, but installing them may require more work than you are willing to perform (the convenience factor strikes again). You may have to run these servers as root and rely on other mechanisms to detect break-ins that might occur through them.

The other big potential root holes in a system are the suid-root and sgid binaries installed on the system. Most of these binaries, such as rlogin, reside in /bin, /sbin, /usr/bin, or /usr/sbin. While nothing is 100% safe, the system-default suid and sgid binaries can be considered reasonably safe. Still, root holes are occasionally found in these binaries. A root hole was found in Xlib in 1998 that made xterm (which is typically suid) vulnerable. It is better to be safe than sorry and the prudent sysadmin will restrict suid binaries, that only staff should run, to a special group that only staff can access, and get rid of (chmod 000) any suid binaries that nobody uses. A server with no display generally does not need an xterm binary. Sgid binaries can be almost as dangerous. If an intruder can break an sgid-kmem binary, the intruder might be able to read /dev/kmem and thus read the encrypted password file, potentially compromising any passworded account. Alternatively an intruder who breaks group kmem can monitor keystrokes sent through pty's, including pty's used by users who login through secure methods. An intruder that breaks the tty group can write to almost any user's tty. If a user is running a terminal program or emulator with a keyboard-simulation feature, the intruder can potentially generate a data stream that causes the user's terminal to echo a command, which is then run as that user.


10.3.3 Securing User Accounts

User accounts are usually the most difficult to secure. While you can impose Draconian access restrictions on your staff and ``star'' out their passwords, you may not be able to do so with any general user accounts you might have. If you do have sufficient control, then you may win out and be able to secure the user accounts properly. If not, you simply have to be more vigilant in your monitoring of those accounts. Use of ssh and Kerberos for user accounts is more problematic, due to the extra administration and technical support required, but still a very good solution compared to a crypted password file.


10.3.4 Securing the Password File

The only sure fire way is to * out as many passwords as you can and use ssh or Kerberos for access to those accounts. Even though the encrypted password file (/etc/spwd.db) can only be read by root, it may be possible for an intruder to obtain read access to that file even if the attacker cannot obtain root-write access.

Your security scripts should always check for and report changes to the password file (see the Checking file integrity section below).


10.3.5 Securing the Kernel Core, Raw Devices, and Filesystems

If an attacker breaks root he can do just about anything, but there are certain conveniences. For example, most modern kernels have a packet sniffing device driver built in. Under FreeBSD it is called the bpf device. An intruder will commonly attempt to run a packet sniffer on a compromised machine. You do not need to give the intruder the capability and most systems do not have the need for the bpf device compiled in.

But even if you turn off the bpf device, you still have /dev/mem and /dev/kmem to worry about. For that matter, the intruder can still write to raw disk devices. Also, there is another kernel feature called the module loader, kldload(8). An enterprising intruder can use a KLD module to install his own bpf device, or other sniffing device, on a running kernel. To avoid these problems you have to run the kernel at a higher secure level, at least securelevel 1. The securelevel can be set with a sysctl on the kern.securelevel variable. Once you have set the securelevel to 1, write access to raw devices will be denied and special chflags flags, such as schg, will be enforced. You must also ensure that the schg flag is set on critical startup binaries, directories, and script files - everything that gets run up to the point where the securelevel is set. This might be overdoing it, and upgrading the system is much more difficult when you operate at a higher secure level. You may compromise and run the system at a higher secure level but not set the schg flag for every system file and directory under the sun. Another possibility is to simply mount / and /usr read-only. It should be noted that being too Draconian in what you attempt to protect may prevent the all-important detection of an intrusion.


10.3.6 Checking File Integrity: Binaries, Configuration Files, Etc.

When it comes right down to it, you can only protect your core system configuration and control files so much before the convenience factor rears its ugly head. For example, using chflags to set the schg bit on most of the files in / and /usr is probably counterproductive, because while it may protect the files, it also closes a detection window. The last layer of your security onion is perhaps the most important - detection. The rest of your security is pretty much useless (or, worse, presents you with a false sense of safety) if you cannot detect potential incursions. Half the job of the onion is to slow down the attacker, rather than stop him, in order to give the detection side of the equation a chance to catch him in the act.

The best way to detect an incursion is to look for modified, missing, or unexpected files. The best way to look for modified files is from another (often centralized) limited-access system. Writing your security scripts on the extra-secure limited-access system makes them mostly invisible to potential attackers, and this is important. In order to take maximum advantage you generally have to give the limited-access box significant access to the other machines in the business, usually either by doing a read-only NFS export of the other machines to the limited-access box, or by setting up ssh key-pairs to allow the limited-access box to ssh to the other machines. Except for its network traffic, NFS is the least visible method - allowing you to monitor the filesystems on each client box virtually undetected. If your limited-access server is connected to the client boxes through a switch, the NFS method is often the better choice. If your limited-access server is connected to the client boxes through a hub, or through several layers of routing, the NFS method may be too insecure (network-wise) and using ssh may be the better choice even with the audit-trail tracks that ssh lays.

Once you give a limited-access box, at least read access to the client systems it is supposed to monitor, you must write scripts to do the actual monitoring. Given an NFS mount, you can write scripts out of simple system utilities such as find(1) and md5(1). It is best to physically md5 the client-box files at least once a day, and to test control files such as those found in /etc and /usr/local/etc even more often. When mismatches are found, relative to the base md5 information the limited-access machine knows is valid, it should scream at a sysadmin to go check it out. A good security script will also check for inappropriate suid binaries and for new or deleted files on system partitions such as / and /usr.

When using ssh rather than NFS, writing the security script is much more difficult. You essentially have to scp the scripts to the client box in order to run them, making them visible, and for safety you also need to scp the binaries (such as find) that those scripts use. The ssh client on the client box may already be compromised. All in all, using ssh may be necessary when running over insecure links, but it is also a lot harder to deal with.

A good security script will also check for changes to user and staff members access configuration files: .rhosts, .shosts, .ssh/authorized_keys and so forth... files that might fall outside the purview of the MD5 check.

If you have a huge amount of user disk space, it may take too long to run through every file on those partitions. In this case, setting mount flags to disallow suid binaries and devices on those partitions is a good idea. The nodev and nosuid options (see mount(8)) are what you want to look into. You should probably scan them anyway, at least once a week, since the object of this layer is to detect a break-in whether or not the break-in is effective.

Process accounting (see accton(8)) is a relatively low-overhead feature of the operating system which might help as a post-break-in evaluation mechanism. It is especially useful in tracking down how an intruder has actually broken into a system, assuming the file is still intact after the break-in occurs.

Finally, security scripts should process the log files, and the logs themselves should be generated in as secure a manner as possible - remote syslog can be very useful. An intruder tries to cover his tracks, and log files are critical to the sysadmin trying to track down the time and method of the initial break-in. One way to keep a permanent record of the log files is to run the system console to a serial port and collect the information on a continuing basis through a secure machine monitoring the consoles.


10.3.7 Paranoia

A little paranoia never hurts. As a rule, a sysadmin can add any number of security features, as long as they do not effect convenience, and can add security features that do effect convenience with some added thought. Even more importantly, a security administrator should mix it up a bit - if you use recommendations such as those given by this document verbatim, you give away your methodologies to the prospective attacker who also has access to this document.


10.3.8 Denial of Service Attacks

This section covers Denial of Service attacks. A DoS attack is typically a packet attack. While there is not much you can do about modern spoofed packet attacks that saturate your network, you can generally limit the damage by ensuring that the attacks cannot take down your servers.

  1. Limiting server forks.

  2. Limiting springboard attacks (ICMP response attacks, ping broadcast, etc.).

  3. Kernel Route Cache.

A common DoS attack is against a forking server that attempts to cause the server to eat processes, file descriptors, and memory, until the machine dies. inetd (see inetd(8)) has several options to limit this sort of attack. It should be noted that while it is possible to prevent a machine from going down, it is not generally possible to prevent a service from being disrupted by the attack. Read the inetd manual page carefully and pay specific attention to the -c, -C, and -R options. Note that spoofed-IP attacks will circumvent the -C option to inetd, so typically a combination of options must be used. Some standalone servers have self-fork-limitation parameters.

Sendmail has its -OMaxDaemonChildren option, which tends to work much better than trying to use sendmail's load limiting options due to the load lag. You should specify a MaxDaemonChildren parameter, when you start sendmail, high enough to handle your expected load, but not so high that the computer cannot handle that number of sendmails without falling on its face. It is also prudent to run sendmail in queued mode (-ODeliveryMode=queued) and to run the daemon (sendmail -bd) separate from the queue-runs (sendmail -q15m). If you still want real-time delivery you can run the queue at a much lower interval, such as -q1m, but be sure to specify a reasonable MaxDaemonChildren option for that sendmail to prevent cascade failures.

Syslogd can be attacked directly and it is strongly recommended that you use the -s option whenever possible, and the -a option otherwise.

You should also be fairly careful with connect-back services such as tcpwrapper's reverse-identd, which can be attacked directly. You generally do not want to use the reverse-ident feature of tcpwrappers for this reason.

It is a very good idea to protect internal services from external access by firewalling them off at your border routers. The idea here is to prevent saturation attacks from outside your LAN, not so much to protect internal services from network-based root compromise. Always configure an exclusive firewall, i.e., ``firewall everything except ports A, B, C, D, and M-Z''. This way you can firewall off all of your low ports except for certain specific services such as named (if you are primary for a zone), ntalkd, sendmail, and other Internet-accessible services. If you try to configure the firewall the other way - as an inclusive or permissive firewall, there is a good chance that you will forget to ``close'' a couple of services, or that you will add a new internal service and forget to update the firewall. You can still open up the high-numbered port range on the firewall, to allow permissive-like operation, without compromising your low ports. Also take note that FreeBSD allows you to control the range of port numbers used for dynamic binding, via the various net.inet.ip.portrange sysctl's (sysctl -a | fgrep portrange), which can also ease the complexity of your firewall's configuration. For example, you might use a normal first/last range of 4000 to 5000, and a hiport range of 49152 to 65535, then block off everything under 4000 in your firewall (except for certain specific Internet-accessible ports, of course).

Another common DoS attack is called a springboard attack - to attack a server in a manner that causes the server to generate responses which overloads the server, the local network, or some other machine. The most common attack of this nature is the ICMP ping broadcast attack. The attacker spoofs ping packets sent to your LAN's broadcast address with the source IP address set to the actual machine they wish to attack. If your border routers are not configured to stomp on ping's to broadcast addresses, your LAN winds up generating sufficient responses to the spoofed source address to saturate the victim, especially when the attacker uses the same trick on several dozen broadcast addresses over several dozen different networks at once. Broadcast attacks of over a hundred and twenty megabits have been measured. A second common springboard attack is against the ICMP error reporting system. By constructing packets that generate ICMP error responses, an attacker can saturate a server's incoming network and cause the server to saturate its outgoing network with ICMP responses. This type of attack can also crash the server by running it out of mbuf's, especially if the server cannot drain the ICMP responses it generates fast enough. The FreeBSD kernel has a new kernel compile option called ICMP_BANDLIM which limits the effectiveness of these sorts of attacks. The last major class of springboard attacks is related to certain internal inetd services such as the udp echo service. An attacker simply spoofs a UDP packet with the source address being server A's echo port, and the destination address being server B's echo port, where server A and B are both on your LAN. The two servers then bounce this one packet back and forth between each other. The attacker can overload both servers and their LANs simply by injecting a few packets in this manner. Similar problems exist with the internal chargen port. A competent sysadmin will turn off all of these inetd-internal test services.

Spoofed packet attacks may also be used to overload the kernel route cache. Refer to the net.inet.ip.rtexpire, rtminexpire, and rtmaxcache sysctl parameters. A spoofed packet attack that uses a random source IP will cause the kernel to generate a temporary cached route in the route table, viewable with netstat -rna | fgrep W3. These routes typically timeout in 1600 seconds or so. If the kernel detects that the cached route table has gotten too big it will dynamically reduce the rtexpire but will never decrease it to less than rtminexpire. There are two problems:

  1. The kernel does not react quickly enough when a lightly loaded server is suddenly attacked.

  2. The rtminexpire is not low enough for the kernel to survive a sustained attack.

If your servers are connected to the Internet via a T3 or better, it may be prudent to manually override both rtexpire and rtminexpire via sysctl(8). Never set either parameter to zero (unless you want to crash the machine). Setting both parameters to 2 seconds should be sufficient to protect the route table from attack.


10.3.9 Access Issues with Kerberos and SSH

There are a few issues with both Kerberos and ssh that need to be addressed if you intend to use them. Kerberos V is an excellent authentication protocol, but there are bugs in the kerberized telnet and rlogin applications that make them unsuitable for dealing with binary streams. Also, by default Kerberos does not encrypt a session unless you use the -x option. ssh encrypts everything by default.

ssh works quite well in every respect except that it forwards encryption keys by default. What this means is that if you have a secure workstation holding keys that give you access to the rest of the system, and you ssh to an insecure machine, your keys are usable. The actual keys themselves are not exposed, but ssh installs a forwarding port for the duration of your login, and if an attacker has broken root on the insecure machine he can utilize that port to use your keys to gain access to any other machine that your keys unlock.

We recommend that you use ssh in combination with Kerberos whenever possible for staff logins. ssh can be compiled with Kerberos support. This reduces your reliance on potentially exposable ssh keys while at the same time protecting passwords via Kerberos. ssh keys should only be used for automated tasks from secure machines (something that Kerberos is unsuited to do). We also recommend that you either turn off key-forwarding in the ssh configuration, or that you make use of the from=IP/DOMAIN option that ssh allows in its authorized_keys file to make the key only usable to entities logging in from specific machines.


10.4 DES, MD5, and Crypt

Parts rewritten and updated by Bill Swingle.

Every user on a UNIX system has a password associated with their account. It seems obvious that these passwords need to be known only to the user and the actual operating system. In order to keep these passwords secret, they are encrypted with what is known as a ``one-way hash'', that is, they can only be easily encrypted but not decrypted. In other words, what we told you a moment ago was obvious is not even true: the operating system itself does not really know the password. It only knows the encrypted form of the password. The only way to get the ``plain-text'' password is by a brute force search of the space of possible passwords.

Unfortunately the only secure way to encrypt passwords when UNIX came into being was based on DES, the Data Encryption Standard. This was not such a problem for users resident in the US, but since the source code for DES could not be exported outside the US, FreeBSD had to find a way to both comply with US law and retain compatibility with all the other UNIX variants that still used DES.

The solution was to divide up the encryption libraries so that US users could install the DES libraries and use DES but international users still had an encryption method that could be exported abroad. This is how FreeBSD came to use MD5 as its default encryption method. MD5 is believed to be more secure than DES, so installing DES is offered primarily for compatibility reasons.


10.4.1 Recognizing Your Crypt Mechanism

Before FreeBSD 4.4 libcrypt.a was a symbolic link pointing to the library which was used for encryption. FreeBSD 4.4 changed libcrypt.a to provide a configurable password authentication hash library. Currently the library supports DES, MD5 and Blowfish hash functions. By default FreeBSD uses MD5 to encrypt passwords.

It is pretty easy to identify which encryption method FreeBSD is set up to use. Examining the encrypted passwords in the /etc/master.passwd file is one way. Passwords encrypted with the MD5 hash are longer than those encrypted with the DES hash and also begin with the characters $1$. Passwords starting with $2$ are encrypted with the Blowfish hash function. DES password strings do not have any particular identifying characteristics, but they are shorter than MD5 passwords, and are coded in a 64-character alphabet which does not include the $ character, so a relatively short string which does not begin with a dollar sign is very likely a DES password.

The password format used for new passwords is controlled by the passwd_format login capability in /etc/login.conf, which takes values of des, md5 or blf. See the login.conf(5) manual page for more information about login capabilities.


10.5 One-time Passwords

S/Key is a one-time password scheme based on a one-way hash function. FreeBSD uses the MD4 hash for compatibility but other systems have used MD5 and DES-MAC. S/Key has been part of the FreeBSD base system since version 1.1.5 and is also used on a growing number of other operating systems. S/Key is a registered trademark of Bell Communications Research, Inc.

From version 5.0 of FreeBSD, S/Key has been replaced with the functionally equivalent OPIE (One-time Passwords In Everything). OPIE uses the MD5 hash by default.

There are three different sorts of passwords which we will discuss below. The first is your usual UNIX style or Kerberos password; we will call this a ``UNIX password''. The second sort is the one-time password which is generated by the S/Key key program or the OPIE opiekey(1) program and accepted by the keyinit or opiepasswd(1) programs and the login prompt; we will call this a ``one-time password''. The final sort of password is the secret password which you give to the key/opiekey programs (and sometimes the keyinit/opiepasswd programs) which it uses to generate one-time passwords; we will call it a ``secret password'' or just unqualified ``password''.

The secret password does not have anything to do with your UNIX password; they can be the same but this is not recommended. S/Key and OPIE secret passwords are not limited to 8 characters like old UNIX passwords[9], they can be as long as you like. Passwords of six or seven word long phrases are fairly common. For the most part, the S/Key or OPIE system operates completely independently of the UNIX password system.

Besides the password, there are two other pieces of data that are important to S/Key and OPIE. One is what is known as the ``seed'' or ``key'', consisting of two letters and five digits. The other is what is called the ``iteration count'', a number between 1 and 100. S/Key creates the one-time password by concatenating the seed and the secret password, then applying the MD4/MD5 hash as many times as specified by the iteration count and turning the result into six short English words. These six English words are your one-time password. The authentication system (primarily PAM) keeps track of the last one-time password used, and the user is authenticated if the hash of the user-provided password is equal to the previous password. Because a one-way hash is used it is impossible to generate future one-time passwords if a successfully used password is captured; the iteration count is decremented after each successful login to keep the user and the login program in sync. When the iteration count gets down to 1, S/Key and OPIE must be reinitialized.

There are three programs involved in each system which we will discuss below. The key and opiekey programs accept an iteration count, a seed, and a secret password, and generate a one-time password or a consecutive list of one-time passwords. The keyinit and opiepasswd programs are used to initialize S/Key and OPIE respectively, and to change passwords, iteration counts, or seeds; they take either a secret passphrase, or an iteration count, seed, and one-time password. The keyinfo and opieinfo programs examine the relevant credentials files (/etc/skeykeys or /etc/opiekeys) and print out the invoking user's current iteration count and seed.

There are four different sorts of operations we will cover. The first is using keyinit or opiepasswd over a secure connection to set up one-time-passwords for the first time, or to change your password or seed. The second operation is using keyinit or opiepasswd over an insecure connection, in conjunction with key or opiekey over a secure connection, to do the same. The third is using key/opiekey to log in over an insecure connection. The fourth is using key or opiekey to generate a number of keys which can be written down or printed out to carry with you when going to some location without secure connections to anywhere.


10.5.1 Secure Connection Initialization

To initialize S/Key for the first time, change your password, or change your seed while logged in over a secure connection (e.g., on the console of a machine or via ssh), use the keyinit command without any parameters while logged in as yourself:

% keyinit
Adding unfurl:
Reminder - Only use this method if you are directly connected.
If you are using telnet or rlogin exit with no password and use keyinit -s.
Enter secret password: 
Again secret password: 

ID unfurl s/key is 99 to17757
DEFY CLUB PRO NASH LACE SOFT

For OPIE, opiepasswd is used instead:

% opiepasswd -c
[grimreaper] ~ $ opiepasswd -f -c
Adding unfurl:
Only use this method from the console; NEVER from remote. If you are using
telnet, xterm, or a dial-in, type ^C now or exit with no password.
Then run opiepasswd without the -c parameter.
Using MD5 to compute responses.
Enter new secret pass phrase:
Again new secret pass phrase:
ID unfurl OTP key is 499 to4268
MOS MALL GOAT ARM AVID COED

At the Enter new secret pass phrase: or Enter secret password: prompts, you should enter a password or phrase. Remember, this is not the password that you will use to login with, this is used to generate your one-time login keys. The ``ID'' line gives the parameters of your particular instance: your login name, the iteration count, and seed. When logging in the system will remember these parameters and present them back to you so you do not have to remember them. The last line gives the particular one-time password which corresponds to those parameters and your secret password; if you were to re-login immediately, this one-time password is the one you would use.


10.5.2 Insecure Connection Initialization

To initialize or change your secret password over an insecure connection, you will need to already have a secure connection to some place where you can run key or opiekey; this might be in the form of a desk accessory on a Macintosh, or a shell prompt on a machine you trust. You will also need to make up an iteration count (100 is probably a good value), and you may make up your own seed or use a randomly-generated one. Over on the insecure connection (to the machine you are initializing), use the keyinit -s command:

% keyinit -s
Updating unfurl:
Old key: to17758
Reminder you need the 6 English words from the key command.
Enter sequence count from 1 to 9999: 100
Enter new key [default to17759]: 
s/key 100 to 17759
s/key access password:
s/key access password:CURE MIKE BANE HIM RACY GORE

For OPIE, you need to use opiepasswd:

% opiepasswd

Updating unfurl:
You need the response from an OTP generator.
Old secret pass phrase:
        otp-md5 498 to4268 ext
        Response: GAME GAG WELT OUT DOWN CHAT
New secret pass phrase:
        otp-md5 499 to4269
        Response: LINE PAP MILK NELL BUOY TROY

ID mark OTP key is 499 gr4269
LINE PAP MILK NELL BUOY TROY

To accept the default seed (which the keyinit program confusingly calls a key), press Return. Then before entering an access password, move over to your secure connection or S/Key desk accessory, and give it the same parameters:

% key 100 to17759
Reminder - Do not use this program while logged in via telnet or rlogin.
Enter secret password: <secret password>
CURE MIKE BANE HIM RACY GORE

Or for OPIE:

% opiekey 498 to4268
Using the MD5 algorithm to compute response.
Reminder: Don't use opiekey from telnet or dial-in sessions.
Enter secret pass phrase:
GAME GAG WELT OUT DOWN CHAT

Now switch back over to the insecure connection, and copy the one-time password generated over to the relevant program.


10.5.3 Generating a Single One-time Password

Once you have initialized S/Key or OPIE, when you login you will be presented with a prompt like this:

% telnet example.com
Trying 10.0.0.1...
Connected to example.com
Escape character is '^]'.

FreeBSD/i386 (example.com) (ttypa)

login: <username>
s/key 97 fw13894
Password:

Or for OPIE:

% telnet example.com
Trying 10.0.0.1...
Connected to example.com
Escape character is '^]'.

FreeBSD/i386 (example.com) (ttypa)

login: <username>
otp-md5 498 gr4269 ext
Password:

As a side note, the S/Key and OPIE prompts have a useful feature (not shown here): if you press Return at the password prompt, the prompter will turn echo on, so you can see what you are typing. This can be extremely useful if you are attempting to type in a password by hand, such as from a printout.

At this point you need to generate your one-time password to answer this login prompt. This must be done on a trusted system that you can run key or opiekey on. (There are versions of these for DOS, Windows and Mac OS as well.) They need both the iteration count and the seed as command line options. You can cut-and-paste these right from the login prompt on the machine that you are logging in to.

On the trusted system:

% key 97 fw13894
Reminder - Do not use this program while logged in via telnet or rlogin.
Enter secret password: 
WELD LIP ACTS ENDS ME HAAG

For OPIE:

% opiekey 498 to4268
Using the MD5 algorithm to compute response.
Reminder: Don't use opiekey from telnet or dial-in sessions.
Enter secret pass phrase:
GAME GAG WELT OUT DOWN CHAT

Now that you have your one-time password you can continue logging in:

login: <username>
s/key 97 fw13894
Password: <return to enable echo>
s/key 97 fw13894
Password [echo on]: WELD LIP ACTS ENDS ME HAAG
Last login: Tue Mar 21 11:56:41 from 10.0.0.2 ...

10.5.4 Generating Multiple One-time Passwords

Sometimes you have to go places where you do not have access to a trusted machine or secure connection. In this case, it is possible to use the key and opiekey commands to generate a number of one-time passwords beforehand to be printed out and taken with you. For example:

% key -n 5 30 zz99999
Reminder - Do not use this program while logged in via telnet or rlogin.
Enter secret password: <secret password>
26: SODA RUDE LEA LIND BUDD SILT 
27: JILT SPY DUTY GLOW COWL ROT  
28: THEM OW COLA RUNT BONG SCOT  
29: COT MASH BARR BRIM NAN FLAG  
30: CAN KNEE CAST NAME FOLK BILK

Or for OPIE:

% opiekey -n 5 30 zz99999
Using the MD5 algorithm to compute response.
Reminder: Don't use opiekey from telnet or dial-in sessions.
Enter secret pass phrase: <secret password>
26: JOAN BORE FOSS DES NAY QUIT
27: LATE BIAS SLAY FOLK MUCH TRIG
28: SALT TIN ANTI LOON NEAL USE
29: RIO ODIN GO BYE FURY TIC
30: GREW JIVE SAN GIRD BOIL PHI

The -n 5 requests five keys in sequence, the 30 specifies what the last iteration number should be. Note that these are printed out in reverse order of eventual use. If you are really paranoid, you might want to write the results down by hand; otherwise you can cut-and-paste into lpr. Note that each line shows both the iteration count and the one-time password; you may still find it handy to scratch off passwords as you use them.


10.5.5 Restricting Use of UNIX® Passwords

S/Key can place restrictions on the use of UNIX passwords based on the host name, user name, terminal port, or IP address of a login session. These restrictions can be found in the configuration file /etc/skey.access. The skey.access(5) manual page has more information on the complete format of the file and also details some security cautions to be aware of before depending on this file for security.

If there is no /etc/skey.access file (this is the default on FreeBSD 4.X systems), then all users will be allowed to use UNIX passwords. If the file exists, however, then all users will be required to use S/Key unless explicitly permitted to do otherwise by configuration statements in the skey.access file. In all cases, UNIX passwords are permitted on the console.

Here is a sample skey.access configuration file which illustrates the three most common sorts of configuration statements:

permit internet 192.168.0.0 255.255.0.0
permit user fnord
permit port ttyd0

The first line (permit internet) allows users whose IP source address (which is vulnerable to spoofing) matches the specified value and mask, to use UNIX passwords. This should not be considered a security mechanism, but rather, a means to remind authorized users that they are using an insecure network and need to use S/Key for authentication.

The second line (permit user) allows the specified username, in this case fnord, to use UNIX passwords at any time. Generally speaking, this should only be used for people who are either unable to use the key program, like those with dumb terminals, or those who are uneducable.

The third line (permit port) allows all users logging in on the specified terminal line to use UNIX passwords; this would be used for dial-ups.

OPIE can restrict the use of UNIX passwords based on the IP address of a login session just like S/Key does. The relevant file is /etc/opieaccess, which is present by default on FreeBSD 5.0 and newer systems. Please check opieaccess(5) for more information on this file and which security considerations you should be aware of when using it.

Here is a sample opieaccess file:

permit 192.168.0.0 255.255.0.0

This line allows users whose IP source address (which is vulnerable to spoofing) matches the specified value and mask, to use UNIX passwords at any time.

If no rules in opieaccess are matched, the default is to deny non-OPIE logins.


10.6 KerberosIV

Contributed by Mark Murray. Based on a contribution by Mark Dapoz.

Kerberos is a network add-on system/protocol that allows users to authenticate themselves through the services of a secure server. Services such as remote login, remote copy, secure inter-system file copying and other high-risk tasks are made considerably safer and more controllable.

The following instructions can be used as a guide on how to set up Kerberos as distributed for FreeBSD. However, you should refer to the relevant manual pages for a complete description.


10.6.1 Installing KerberosIV

Kerberos is an optional component of FreeBSD. The easiest way to install this software is by selecting the krb4 or krb5 distribution in sysinstall during the initial installation of FreeBSD. This will install the ``eBones'' (KerberosIV) or ``Heimdal'' (Kerberos5) implementation of Kerberos. These implementations are included because they are developed outside the USA/Canada and were thus available to system owners outside those countries during the era of restrictive export controls on cryptographic code from the USA.

Alternatively, the MIT implementation of Kerberos is available from the ports collection as security/krb5.


10.6.2 Creating the Initial Database

This is done on the Kerberos server only. First make sure that you do not have any old Kerberos databases around. You should change to the directory /etc/kerberosIV and check that only the following files are present:

# cd /etc/kerberosIV
# ls
README      krb.conf        krb.realms

If any additional files (such as principal.* or master_key) exist, then use the kdb_destroy command to destroy the old Kerberos database, or if Kerberos is not running, simply delete the extra files.

You should now edit the krb.conf and krb.realms files to define your Kerberos realm. In this case the realm will be EXAMPLE.COM and the server is grunt.example.com. We edit or create the krb.conf file:

# cat krb.conf
EXAMPLE.COM
EXAMPLE.COM grunt.example.com admin server
CS.BERKELEY.EDU okeeffe.berkeley.edu
ATHENA.MIT.EDU kerberos.mit.edu
ATHENA.MIT.EDU kerberos-1.mit.edu
ATHENA.MIT.EDU kerberos-2.mit.edu
ATHENA.MIT.EDU kerberos-3.mit.edu
LCS.MIT.EDU kerberos.lcs.mit.edu
TELECOM.MIT.EDU bitsy.mit.edu
ARC.NASA.GOV trident.arc.nasa.gov

In this case, the other realms do not need to be there. They are here as an example of how a machine may be made aware of multiple realms. You may wish to not include them for simplicity.

The first line names the realm in which this system works. The other lines contain realm/host entries. The first item on a line is a realm, and the second is a host in that realm that is acting as a ``key distribution center''. The words admin server following a host's name means that host also provides an administrative database server. For further explanation of these terms, please consult the Kerberos manual pages.

Now we have to add grunt.example.com to the EXAMPLE.COM realm and also add an entry to put all hosts in the .example.com domain in the EXAMPLE.COM realm. The krb.realms file would be updated as follows:

# cat krb.realms
grunt.example.com EXAMPLE.COM
.example.com EXAMPLE.COM
.berkeley.edu CS.BERKELEY.EDU
.MIT.EDU ATHENA.MIT.EDU
.mit.edu ATHENA.MIT.EDU

Again, the other realms do not need to be there. They are here as an example of how a machine may be made aware of multiple realms. You may wish to remove them to simplify things.

The first line puts the specific system into the named realm. The rest of the lines show how to default systems of a particular subdomain to a named realm.

Now we are ready to create the database. This only needs to run on the Kerberos server (or Key Distribution Center). Issue the kdb_init command to do this:

# kdb_init
Realm name [default  ATHENA.MIT.EDU ]: EXAMPLE.COM
You will be prompted for the database Master Password.
It is important that you NOT FORGET this password.
        
Enter Kerberos master key:

Now we have to save the key so that servers on the local machine can pick it up. Use the kstash command to do this:

# kstash
          
Enter Kerberos master key:

Current Kerberos master key version is 1.

Master key entered. BEWARE!

This saves the encrypted master password in /etc/kerberosIV/master_key.


10.6.3 Making It All Run

Two principals need to be added to the database for each system that will be secured with Kerberos. Their names are kpasswd and rcmd. These two principals are made for each system, with the instance being the name of the individual system.

These daemons, kpasswd and rcmd allow other systems to change Kerberos passwords and run commands like rcp(1), rlogin(1) and rsh(1).

Now let us add these entries:

# kdb_edit
Opening database...

Enter Kerberos master key:

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
Previous or default values are in [brackets] ,
enter return to leave the same, or new value.

Principal name: passwd
Instance: grunt

<Not found>, Create [y] ? y

Principal: passwd, Instance: grunt, kdc_key_ver: 1
New Password:                    <---- enter RANDOM here
Verifying password

New Password: <---- enter RANDOM here

Random password [y] ? y

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ?
Max ticket lifetime (*5 minutes) [ 255 ] ?
Attributes [ 0 ] ?
Edit O.K.
Principal name: rcmd
Instance: grunt

<Not found>, Create [y] ?

Principal: rcmd, Instance: grunt, kdc_key_ver: 1
New Password:       <---- enter RANDOM here
Verifying password

New Password:           <---- enter RANDOM here

Random password [y] ?

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ?
Max ticket lifetime (*5 minutes) [ 255 ] ?
Attributes [ 0 ] ?
Edit O.K.
Principal name:         <---- null entry here will cause an exit

10.6.4 Creating the Server File

We now have to extract all the instances which define the services on each machine. For this we use the ext_srvtab command. This will create a file which must be copied or moved by secure means to each Kerberos client's /etc/kerberosIV directory. This file must be present on each server and client, and is crucial to the operation of Kerberos.

# ext_srvtab grunt
Enter Kerberos master key:
        
Current Kerberos master key version is 1.

Master key entered. BEWARE!
Generating 'grunt-new-srvtab'....

Now, this command only generates a temporary file which must be renamed to srvtab so that all the servers can pick it up. Use the mv(1) command to move it into place on the original system:

# mv grunt-new-srvtab srvtab

If the file is for a client system, and the network is not deemed safe, then copy the client-new-srvtab to removable media and transport it by secure physical means. Be sure to rename it to srvtab in the client's /etc/kerberosIV directory, and make sure it is mode 600:

# mv grumble-new-srvtab srvtab
# chmod 600 srvtab

10.6.5 Populating the Database

We now have to add some user entries into the database. First let us create an entry for the user jane. Use the kdb_edit command to do this:

# kdb_edit
Opening database...

Enter Kerberos master key:

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
Previous or default values are in [brackets] ,
enter return to leave the same, or new value.

Principal name: jane
Instance:

<Not found>, Create [y] ? y

Principal: jane, Instance: , kdc_key_ver: 1
New Password:                <---- enter a secure password here
Verifying password

New Password:                <---- re-enter the password here
Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ?
Max ticket lifetime (*5 minutes) [ 255 ] ?
Attributes [ 0 ] ?
Edit O.K.
Principal name:          <---- null entry here will cause an exit

10.6.6 Testing It All Out

First we have to start the Kerberos daemons. Note that if you have correctly edited your /etc/rc.conf then this will happen automatically when you reboot. This is only necessary on the Kerberos server. Kerberos clients will automatically get what they need from the /etc/kerberosIV directory.

# kerberos &
Kerberos server starting
Sleep forever on error
Log file is /var/log/kerberos.log
Current Kerberos master key version is 1.

Master key entered. BEWARE!

Current Kerberos master key version is 1
Local realm: EXAMPLE.COM
# kadmind -n &
KADM Server KADM0.0A initializing
Please do not use 'kill -9' to kill this job, use a
regular kill instead

Current Kerberos master key version is 1.

Master key entered.  BEWARE!

Now we can try using the kinit command to get a ticket for the ID jane that we created above:

% kinit jane
MIT Project Athena (grunt.example.com)
Kerberos Initialization for "jane"
Password:

Try listing the tokens using klist to see if we really have them:

% klist
Ticket file:    /tmp/tkt245
Principal:      jane@EXAMPLE.COM

  Issued           Expires          Principal
Apr 30 11:23:22  Apr 30 19:23:22  krbtgt.EXAMPLE.COM@EXAMPLE.COM

Now try changing the password using passwd(1) to check if the kpasswd daemon can get authorization to the Kerberos database:

% passwd
realm EXAMPLE.COM
Old password for jane:
New Password for jane:
Verifying password
New Password for jane:
Password changed.

10.6.7 Adding su Privileges

Kerberos allows us to give each user who needs root privileges their own separate su(1) password. We could now add an ID which is authorized to su(1) to root. This is controlled by having an instance of root associated with a principal. Using kdb_edit we can create the entry jane.root in the Kerberos database:

# kdb_edit
Opening database...

Enter Kerberos master key:

Current Kerberos master key version is 1.

Master key entered.  BEWARE!
Previous or default values are in [brackets] ,
enter return to leave the same, or new value.

Principal name: jane
Instance: root

<Not found>, Create [y] ? y

Principal: jane, Instance: root, kdc_key_ver: 1
New Password:                    <---- enter a SECURE password here
Verifying password

New Password:            <---- re-enter the password here

Principal's new key version = 1
Expiration date (enter yyyy-mm-dd) [ 2000-01-01 ] ?
Max ticket lifetime (*5 minutes) [ 255 ] ? 12 <--- Keep this short!
Attributes [ 0 ] ?
Edit O.K.
Principal name:                <---- null entry here will cause an exit

Now try getting tokens for it to make sure it works:

# kinit jane.root
MIT Project Athena (grunt.example.com)
Kerberos Initialization for "jane.root"
Password:

Now we need to add the user to root's .klogin file:

# cat /root/.klogin
jane.root@EXAMPLE.COM

Now try doing the su(1):

% su
Password:

and take a look at what tokens we have:

# klist
Ticket file:    /tmp/tkt_root_245
Principal:      jane.root@EXAMPLE.COM

  Issued           Expires          Principal
May  2 20:43:12  May  3 04:43:12  krbtgt.EXAMPLE.COM@EXAMPLE.COM

10.6.8 Using Other Commands

In an earlier example, we created a principal called jane with an instance root. This was based on a user with the same name as the principal, and this is a Kerberos default; that a <principal>.<instance> of the form <username>.root will allow that <username> to su(1) to root if the necessary entries are in the .klogin file in root's home directory:

# cat /root/.klogin
jane.root@EXAMPLE.COM

Likewise, if a user has in their own home directory lines of the form:

% cat ~/.klogin
jane@EXAMPLE.COM
jack@EXAMPLE.COM

This allows anyone in the EXAMPLE.COM realm who has authenticated themselves as jane or jack (via kinit, see above) to access to jane's account or files on this system (grunt) via rlogin(1), rsh(1) or rcp(1).

For example, jane now logs into another system using Kerberos:

% kinit
MIT Project Athena (grunt.example.com)
Password:
% rlogin grunt
Last login: Mon May  1 21:14:47 from grumble
Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994
        The Regents of the University of California.   All rights reserved.

FreeBSD BUILT-19950429 (GR386) #0: Sat Apr 29 17:50:09 SAT 1995

Or jack logs into jane's account on the same machine (jane having set up the .klogin file as above, and the person in charge of Kerberos having set up principal jack with a null instance):

% kinit
% rlogin grunt -l jane
MIT Project Athena (grunt.example.com)
Password:
Last login: Mon May  1 21:16:55 from grumble
Copyright (c) 1980, 1983, 1986, 1988, 1990, 1991, 1993, 1994
        The Regents of the University of California.   All rights reserved.
FreeBSD BUILT-19950429 (GR386) #0: Sat Apr 29 17:50:09 SAT 1995

10.7 Kerberos5

Contributed by Tillman Hodgson. Based on a contribution by Mark Murray.

Every FreeBSD release beyond FreeBSD-5.1 includes support only for Kerberos5. Hence Kerberos5 is the only version included, and its configuration is similar in many aspects to that of KerberosIV. The following information only applies to Kerberos5 in post FreeBSD-5.0 releases. Users who wish to use the KerberosIV package may install the security/krb4 port.

Kerberos is a network add-on system/protocol that allows users to authenticate themselves through the services of a secure server. Services such as remote login, remote copy, secure inter-system file copying and other high-risk tasks are made considerably safer and more controllable.

Kerberos can be described as an identity-verifying proxy system. It can also be described as a trusted third-party authentication system. Kerberos provides only one function -- the secure authentication of users on the network. It does not provide authorization functions (what users are allowed to do) or auditing functions (what those users did). After a client and server have used Kerberos to prove their identity, they can also encrypt all of their communications to assure privacy and data integrity as they go about their business.

Therefore it is highly recommended that Kerberos be used with other security methods which provide authorization and audit services.

The following instructions can be used as a guide on how to set up Kerberos as distributed for FreeBSD. However, you should refer to the relevant manual pages for a complete description.

For purposes of demonstrating a Kerberos installation, the various namespaces will be handled as follows:

  • The DNS domain (``zone'') will be example.org.

  • The Kerberos realm will be EXAMPLE.ORG.

Note: Please use real domain names when setting up Kerberos even if you intend to run it internally. This avoids DNS problems and assures inter-operation with other Kerberos realms.


10.7.1 History

Kerberos was created by MIT as a solution to network security problems. The Kerberos protocol uses strong cryptography so that a client can prove its identity to a server (and vice versa) across an insecure network connection.

Kerberos is both the name of a network authentication protocol and an adjective to describe programs that implement the program (Kerberos telnet, for example). The current version of the protocol is version 5, described in RFC 1510.

Several free implementations of this protocol are available, covering a wide range of operating systems. The Massachusetts Institute of Technology (MIT), where Kerberos was originally developed, continues to develop their Kerberos package. It is commonly used in the US as a cryptography product, as such it has historically been affected by US export regulations. The MIT Kerberos is available as a port (security/krb5). Heimdal Kerberos is another version 5 implementation, and was explicitly developed outside of the US to avoid export regulations (and is thus often included in non-commercial UNIX variants). The Heimdal Kerberos distribution is available as a port (security/heimdal), and a minimal installation of it is included in the base FreeBSD install.

In order to reach the widest audience, these instructions assume the use of the Heimdal distribution included in FreeBSD.


10.7.2 Setting up a Heimdal KDC

The Key Distribution Center (KDC) is the centralized authentication service that Kerberos provides -- it is the computer that issues Kerberos tickets. The KDC is considered ``trusted'' by all other computers in the Kerberos realm, and thus has heightened security concerns.

Note that while running the Kerberos server requires very few computing resources, a dedicated machine acting only as a KDC is recommended for security reasons.

To begin setting up a KDC, ensure that your /etc/rc.conf file contains the correct settings to act as a KDC (you may need to adjust paths to reflect your own system):

kerberos5_server_enable="YES"
kadmind5_server_enable="YES"
kerberos_stash="YES"

Note: The kerberos_stash is only available in FreeBSD 4.X.

Next we will set up your Kerberos config file, /etc/krb5.conf:

[libdefaults]
    default_realm = EXAMPLE.ORG
[realms]
    EXAMPLE.ORG = {
        kdc = kerberos.example.org
    }
[domain_realm]
    .example.org = EXAMPLE.ORG

Note that this /etc/krb5.conf file implies that your KDC will have the fully-qualified hostname of kerberos.example.org. You will need to add a CNAME (alias) entry to your zone file to accomplish this if your KDC has a different hostname.

Note: For large networks with a properly configured BIND DNS server, the above example could be trimmed to:

[libdefaults]
      default_realm = EXAMPLE.ORG

With the following lines being appended to the example.org zonefile:

_kerberos._udp      IN  SRV     01 00 88 kerberos.example.org.
_kerberos._tcp      IN  SRV     01 00 88 kerberos.example.org.
_kpasswd._udp       IN  SRV     01 00 464 kerberos.example.org.
_kerberos-adm._tcp  IN  SRV     01 00 749 kerberos.example.org.
_kerberos           IN  TXT     EXAMPLE.ORG.

Next we will create the Kerberos database. This database contains the keys of all principals encrypted with a master password. You are not required to remember this password, it will be stored in a file (/var/heimdal/m-key). To create the master key, run kstash and enter a password.

Once the master key has been created, you can initialize the database using the kadmin program with the -l option (standing for ``local''). This option instructs kadmin to modify the database files directly rather than going through the kadmind network service. This handles the chicken-and-egg problem of trying to connect to the database before it is created. Once you have the kadmin prompt, use the init command to create your realms initial database.

Lastly, while still in kadmin, create your first principal using the add command. Stick to the defaults options for the principal for now, you can always change them later with the modify command. Note that you can use the ? command at any prompt to see the available options.

A sample database creation session is shown below:

# kstash
      Master key: xxxxxxxx
      Verifying password - Master key: xxxxxxxx

      # kadmin -l
      kadmin> init EXAMPLE.ORG
      Realm max ticket life [unlimited]:
      kadmin> add tillman
      Max ticket life [unlimited]:
      Max renewable life [unlimited]:
      Attributes []:
      Password: xxxxxxxx
      Verifying password - Password: xxxxxxxx

Now it is time to start up the KDC services. Run /etc/rc.d/kerberos start and /etc/rc.d/kadmind start to bring up the services. Note that you won't have any kerberized daemons running at this point but you should be able to confirm the that the KDC is functioning by obtaining and listing a ticket for the principal (user) that you just created from the command-line of the KDC itself:

%k5init tillman
      tillman@EXAMPLE.ORG's Password:

      %k5list
      Credentials cache: FILE:/tmp/krb5cc_500
      Principal: tillman@EXAMPLE.ORG

              Issued           Expires          Principal
              Aug 27 15:37:58  Aug 28 01:37:58  krbtgt/EXAMPLE.ORG@EXAMPLE.ORG
              Aug 27 15:37:58  Aug 28 01:37:58  krbtgt/EXAMPLE.ORG@EXAMPLE.ORG

      v4-ticket file: /tmp/tkt500
      k5list: No ticket file (tf_util)

10.7.3 Kerberos enabling a server with Heimdal services

First, we need a copy of the Kerberos configuration file, /etc/krb5.conf. To do so, simply copy it over to the client computer from the KDC in a secure fashion (using network utilities, such as scp(1), or physically via a floppy disk).

Next you need a /etc/krb5.keytab file. This is the major difference between a server providing Kerberos enabled daemons and a workstation -- the server must have a keytab file. This file contains the servers host key, which allows it and the KDC to verify each others identity. It must be transmitted to the server in a secure fashion, as the security of the server can be broken if the key is made public. This explicitly means that transferring it via a clear text channel, such as FTP, is a very bad idea.

Typically, you transfer to the keytab to the server using the kadmin program. This is handy because you also need to create the host principal (the KDC end of the krb5.keytab) using kadmin.

Note that you must have already obtained a ticket and that this ticket must be allowed to use the kadmin interface in the kadmind.acl. See the section titled ``Remote administration'' in the Heimdal info pages (info heimdal) for details on designing access control lists. If you do not want to enable remote kadmin access, you can simply securely connect to the KDC (via local console, ssh(1) or Kerberos telnet(1)) and perform administration locally using kadmin -l.

After installing the /etc/krb5.conf file, you can use kadmin from the Kerberos server. The add --random-key command will let you add the servers host principal, and the ext command will allow you to extract the servers host principal to its own keytab. For example:

# kadmin
    kadmin> add --random-key host/myserver.EXAMPLE.ORG
    Max ticket life [unlimited]:
    Max renewable life [unlimited]:
    Attributes []:
    kadmin> ext host/myserver.EXAMPLE.ORG
    kadmin> exit

Note that the ext command (short for ``extract'') stores the extracted key in /etc/krb5.keytab by default.

If you do not have kadmind running on the KDC (possibly for security reasons) and thus do not have access to kadmin remotely, you can add the host principal (host/myserver.EXAMPLE.ORG) directly on the KDC and then extract it to a temporary file (to avoid over-writing the /etc/krb5.keytab on the KDC) using something like this:

# kadmin
    kadmin> ext --keytab=/tmp/example.keytab host/myserver.example.org
    kadmin> exit

You can then securely copy the keytab to the server computer (using scp or a floppy, for example). Be sure to specify a non-default keytab name to avoid over-writing the keytab on the KDC.

At this point your server can communicate with the KDC (due to its krb5.conf file) and it can prove its own identity (due to the krb5.keytab file). It is now ready for you to enable some Kerberos services. For this example we will enable the telnet service by putting a line like this into your /etc/inetd.conf and then restarting the inetd(8) service with /etc/rc.d/inetd restart:

telnet    stream  tcp     nowait  root    /usr/libexec/telnetd  telnetd -a user

The critical bit is that the -a (for authentication) type is set to user. Consult the telnetd(8) manual page for more details.


10.7.4 Kerberos enabling a client with Heimdal

Setting up a client computer is almost trivially easy. As far as Kerberos configuration goes, you only need the Kerberos configuration file, located at /etc/krb5.conf. Simply securely copy it over to the client computer from the KDC.

Test your client computer by attempting to use kinit, klist, and kdestroy from the client to obtain, show, and then delete a ticket for the principal you created above. You should also be able to use Kerberos applications to connect to Kerberos enabled servers, though if that does not work and obtaining a ticket does the problem is likely with the server and not with the client or the KDC.

When testing an application like telnet, try using a packet sniffer (such as tcpdump(1)) to confirm that your password is not sent in the clear. Try using telnet with the -x option, which encrypts the entire data stream (similar to ssh).

The core Kerberos client applications (traditionally named kinit, klist, kdestroy, and kpasswd) are installed in the base FreeBSD install. Note that FreeBSD versions prior to 5.0 renamed them to k5init, k5list, k5destroy, k5passwd, and k5stash (though it is typically only used once).

Various non-core Kerberos client applications are also installed by default. This is where the ``minimal'' nature of the base Heimdal installation is felt: telnet is the only Kerberos enabled service.

The Heimdal port adds some of the missing client applications: Kerberos enabled versions of ftp, rsh, rcp, rlogin, and a few other less common programs. The MIT port also contains a full suite of Kerberos client applications.


10.7.5 User configuration files: .k5login and .k5users

Users within a realm typically have their Kerberos principal (such as tillman@EXAMPLE.ORG) mapped to a local user account (such as a local account named tillman). Client applications such as telnet usually do not require a user name or a principal.

Occasionally, however, you want to grant access to a local user account to someone who does not have a matching Kerberos principal. For example, tillman@EXAMPLE.ORG may need access to the local user account webdevelopers. Other principals may also need access to that local account.

The .k5login and .k5users files, placed in a users home directory, can be used similar to a powerful combination of .hosts and .rhosts, solving this problem. For example, if a .k5login with the following contents:

tillman@example.org
    jdoe@example.org

Were to be placed into the home directory of the local user webdevelopers then both principals listed would have access to that account without requiring a shared password.

Reading the man pages for these commands is recommended. Note that the ksu man page covers .k5users.


10.7.6 Kerberos Tips, Tricks, and Troubleshooting

  • When using either the Heimdal or MIT Kerberos ports ensure that your PATH environment variable lists the Kerberos versions of the client applications before the system versions.

  • Is your time in sync? Are you sure? If the time is not in sync (typically within five minutes) authentication will fail.

  • MIT and Heimdal inter-operate nicely. Except for kadmin, the protocol for which is not standardized.

  • If you change your hostname, you also need to change your host/ principal and update your keytab. This also applies to special keytab entries like the www/ principal used for Apache's www/mod_auth_kerb.

  • All hosts in your realm must be resolvable (both forwards and reverse) in DNS (or /etc/hosts as a minimum). CNAMEs will work, but the A and PTR records must be correct and in place. The error message isn't very intuitive: ``Kerberos5 refuses authentication because Read req failed: Key table entry not found''.

  • Some operating systems that may being acting as clients to your KDC do not set the permissions for ksu to be setuid root. This means that ksu does not work, which is a good security idea but annoying. This is not a KDC error.

  • With MIT Kerberos, if you want to allow a principal to have a ticket life longer than the default ten hours, you must use modify_principal in kadmin to change the maxlife of both the principal in question and the krbtgt principal. Then the principal can use the -l option with kinit to request a ticket with a longer lifetime.

  • Note: If you run a packet sniffer on your KDC to add in troubleshooting and then run kinit from a workstation, you will notice that your TGT is sent immediately upon running kinit -- even before you type your password! The explanation is that the Kerberos server freely transmits a TGT (Ticket Granting Ticket) to any unauthorized request; however, every TGT is encrypted in a key derived from the user's password. Therefore, when a user types their password it is not being sent to the KDC, it is being used to decrypt the TGT that kinit already obtained. If the decryption process results in a valid ticket with a valid time stamp, the user has valid Kerberos credentials. These credentials include a session key for establishing secure communications with the Kerberos server in the future, as well as the actual ticket-granting ticket, which is actually encrypted with the Kerberos server's own key. This second layer of encryption is unknown to the user, but it is what allows the Kerberos server to verify the authenticity of each TGT.

  • You have to keep the time in sync between all the computers in your realm. NTP is perfect for this. For more information on NTP, see Section 19.12.

  • If you want to use long ticket lifetimes (a week, for example) and you are using OpenSSH to connect to the machine where your ticket is stored, make sure that Kerberos TicketCleanup is set to no in your sshd_config or else your tickets will be deleted when you log out.

  • Remember that host principals can have a longer ticket lifetime as well. If your user principal has a lifetime of a week but the host you are connecting to has a lifetime of nine hours, you will have an expired host principal in your cache and the ticket cache will not work as expected.

  • When setting up a krb5.dict file to prevent specific bad passwords from being used (the manual page for kadmind covers this briefly), remember that it only applies to principals that have a password policy assigned to them. The krb5.dict files format is simple: one string per line. Creating a symbolic link to /usr/share/dict/words might be useful.


10.7.7 Differences with the MIT port

The major difference between the MIT and Heimdal installs relates to the kadmin program which has a different (but equivalent) set of commands and uses a different protocol. This has a large implications if your KDC is MIT as you will not be able to use the Heimdal kadmin program to administer your KDC remotely (or vice versa, for that matter).

The client applications may also take slightly different command line options to accomplish the same tasks. Following the instructions on the MIT Kerberos web site (http://web.mit.edu/Kerberos/www/) is recommended. Be careful of path issues: the MIT port installs into /usr/local/ by default, and the ``normal'' system applications may be run instead of MIT if your PATH environment variable lists the system directories first.

Note: With the MIT security/krb5 port that is provided by FreeBSD, be sure to read the /usr/local/share/doc/krb5/README.FreeBSD file installed by the port if you want to understand why logins via telnetd and klogind behave somewhat oddly. Most importantly, correcting the ``incorrect permissions on cache file'' behavior requires that the login.krb5 binary be used for authentication so that it can properly change ownership for the forwarded credentials.


10.7.8 Mitigating limitations found in Kerberos


10.7.8.1 Kerberos is an all-or-nothing approach

Every service enabled on the network must be modified to work with Kerberos (or be otherwise secured against network attacks) or else the users credentials could be stolen and re-used. An example of this would be Kerberos enabling all remote shells (via rsh and telnet, for example) but not converting the POP3 mail server which sends passwords in plaintext.


10.7.8.2 Kerberos is intended for single-user workstations

In a multi-user environment, Kerberos is less secure. This is because it stores the tickets in the /tmp directory, which is readable by all users. If a user is sharing a computer with several other people simultaneously (i.e. multi-user), it is possible that the user's tickets can be stolen (copied) by another user.

This can be overcome with the -c filename command-line option or (preferably) the KRB5CCNAME environment variable, but this is rarely done. In principal, storing the ticket in the users home directory and using simple file permissions can mitigate this problem.


10.7.8.3 The KDC is a single point of failure

By design, the KDC must be as secure as the master password database is contained on it. The KDC should have absolutely no other services running on it and should be physically secured. The danger is high because Kerberos stores all passwords encrypted with the same key (the ``master'' key), which in turn is stored as a file on the KDC.

As a side note, a compromised master key is not quite as bad as one might normally fear. The master key is only used to encrypt the Kerberos database and as a seed for the random number generator. As long as access to your KDC is secure, an attacker cannot do much with the master key.

Additionally, if the KDC is unavailable (perhaps due to a denial of service attack or network problems) the network services are unusable as authentication can not be performed, a recipe for a denial-of-service attack. This can alleviated with multiple KDCs (a single master and one or more slaves) and with careful implementation of secondary or fall-back authentication (PAM is excellent for this).


10.7.8.4 Kerberos Shortcomings

Kerberos allows users, hosts and services to authenticate between themselves. It does not have a mechanism to authenticate the KDC to the users, hosts or services. This means that a trojanned kinit (for example) could record all user names and passwords. Something like security/tripwire or other file system integrity checking tools can alleviate this.


10.8 Firewalls

Contributed by Gary Palmer and Alex Nash.

Firewalls are an area of increasing interest for people who are connected to the Internet, and are even finding applications on private networks to provide enhanced security. This section will hopefully explain what firewalls are, how to use them, and how to use the facilities provided in the FreeBSD kernel to implement them.

Note: People often think that having a firewall between your internal network and the ``Big Bad Internet'' will solve all your security problems. It may help, but a poorly set up firewall system is more of a security risk than not having one at all. A firewall can add another layer of security to your systems, but it cannot stop a really determined cracker from penetrating your internal network. If you let internal security lapse because you believe your firewall to be impenetrable, you have just made the crackers job that much easier.


10.8.1 What Is a Firewall?

There are currently two distinct types of firewalls in common use on the Internet today. The first type is more properly called a packet filtering router. This type of firewall utilizes a multi-homed machine and a set of rules to determine whether to forward or block individual packets. A multi-homed machine is simply a device with multiple network interfaces. The second type, known as a proxy server, relies on daemons to provide authentication and to forward packets, possibly on a multi-homed machine which has kernel packet forwarding disabled.

Sometimes sites combine the two types of firewalls, so that only a certain machine (known as a bastion host) is allowed to send packets through a packet filtering router onto an internal network. Proxy services are run on the bastion host, which are generally more secure than normal authentication mechanisms.

FreeBSD comes with a kernel packet filter (known as IPFW), which is what the rest of this section will concentrate on. Proxy servers can be built on FreeBSD from third party software, but there is such a variety of proxy servers available that it would be impossible to cover them in this section.


10.8.1.1 Packet Filtering Routers

A router is a machine which forwards packets between two or more networks. A packet filtering router is programmed to compare each packet to a list of rules before deciding if it should be forwarded or not. Most modern IP routing software includes packet filtering functionality that defaults to forwarding all packets. To enable the filters, you need to define a set of rules.

To decide whether a packet should be passed on, the firewall looks through its set of rules for a rule which matches the contents of the packet's headers. Once a match is found, the rule action is obeyed. The rule action could be to drop the packet, to forward the packet, or even to send an ICMP message back to the originator. Only the first match counts, as the rules are searched in order. Hence, the list of rules can be referred to as a ``rule chain''.

The packet-matching criteria varies depending on the software used, but typically you can specify rules which depend on the source IP address of the packet, the destination IP address, the source port number, the destination port number (for protocols which support ports), or even the packet type (UDP, TCP, ICMP, etc).


10.8.1.2 Proxy Servers

Proxy servers are machines which have had the normal system daemons (telnetd, ftpd, etc) replaced with special servers. These servers are called proxy servers, as they normally only allow onward connections to be made. This enables you to run (for example) a proxy telnet server on your firewall host, and people can telnet in to your firewall from the outside, go through some authentication mechanism, and then gain access to the internal network (alternatively, proxy servers can be used for signals coming from the internal network and heading out).

Proxy servers are normally more secure than normal servers, and often have a wider variety of authentication mechanisms available, including ``one-shot'' password systems so that even if someone manages to discover what password you used, they will not be able to use it to gain access to your systems as the password expires immediately after the first use. As they do not actually give users access to the host machine, it becomes a lot more difficult for someone to install backdoors around your security system.

Proxy servers often have ways of restricting access further, so that only certain hosts can gain access to the servers. Most will also allow the administrator to specify which users can talk to which destination machines. Again, what facilities are available depends largely on what proxy software you choose.


10.8.2 What Does IPFW Allow Me to Do?

IPFW, the software supplied with FreeBSD, is a packet filtering and accounting system which resides in the kernel, and has a user-land control utility, ipfw(8). Together, they allow you to define and query the rules used by the kernel in its routing decisions.

There are two related parts to IPFW. The firewall section performs packet filtering. There is also an IP accounting section which tracks usage of the router, based on rules similar to those used in the firewall section. This allows the administrator to monitor how much traffic the router is getting from a certain machine, or how much WWW traffic it is forwarding, for example.

As a result of the way that IPFW is designed, you can use IPFW on non-router machines to perform packet filtering on incoming and outgoing connections. This is a special case of the more general use of IPFW, and the same commands and techniques should be used in this situation.


10.8.3 Enabling IPFW on FreeBSD

As the main part of the IPFW system lives in the kernel, you will need to add one or more options to your kernel configuration file, depending on what facilities you want, and recompile your kernel. See "Reconfiguring your Kernel" (Chapter 9) for more details on how to recompile your kernel.

Warning: IPFW defaults to a policy of deny ip from any to any. If you do not add other rules during startup to allow access, you will lock yourself out of the server upon rebooting into a firewall-enabled kernel. We suggest that you set firewall_type=open in your /etc/rc.conf file when first enabling this feature, then refining the firewall rules in /etc/rc.firewall after you have tested that the new kernel feature works properly. To be on the safe side, you may wish to consider performing the initial firewall configuration from the local console rather than via ssh. Another option is to build a kernel using both the IPFIREWALL and IPFIREWALL_DEFAULT_TO_ACCEPT options. This will change the default rule of IPFW to allow ip from any to any and avoid the possibility of a lockout.

There are currently four kernel configuration options relevant to IPFW:

options IPFIREWALL

Compiles into the kernel the code for packet filtering.

options IPFIREWALL_VERBOSE

Enables code to allow logging of packets through syslogd(8). Without this option, even if you specify that packets should be logged in the filter rules, nothing will happen.

options IPFIREWALL_VERBOSE_LIMIT=10

Limits the number of packets logged through syslogd(8) on a per entry basis. You may wish to use this option in hostile environments in which you want to log firewall activity, but do not want to be open to a denial of service attack via syslog flooding.

When a chain entry reaches the packet limit specified, logging is turned off for that particular entry. To resume logging, you will need to reset the associated counter using the ipfw(8) utility:

# ipfw zero 4500

Where 4500 is the chain entry you wish to continue logging.

options IPFIREWALL_DEFAULT_TO_ACCEPT

This changes the default rule action from ``deny'' to ``allow''. This avoids the possibility of locking yourself out if you happen to boot a kernel with IPFIREWALL support but have not configured your firewall yet. It is also very useful if you often use ipfw(8) as a filter for specific problems as they arise. Use with care though, as this opens up the firewall and changes the way it works.

Note: Previous versions of FreeBSD contained an IPFIREWALL_ACCT option. This is now obsolete as the firewall code automatically includes accounting facilities.


10.8.4 Configuring IPFW

The configuration of the IPFW software is done through the ipfw(8) utility. The syntax for this command looks quite complicated, but it is relatively simple once you understand its structure.

There are currently four different command categories used by the utility: addition/deletion, listing, flushing, and clearing. Addition/deletion is used to build the rules that control how packets are accepted, rejected, and logged. Listing is used to examine the contents of your rule set (otherwise known as the chain) and packet counters (accounting). Flushing is used to remove all entries from the chain. Clearing is used to zero out one or more accounting entries.


10.8.4.1 Altering the IPFW Rules

The syntax for this form of the command is:

ipfw [-N] command [index] action [log] protocol addresses [options]



There is one valid flag when using this form of the command:

-N

Resolve addresses and service names in output.

The command given can be shortened to the shortest unique form. The valid commands are:

add

Add an entry to the firewall/accounting rule list

delete

Delete an entry from the firewall/accounting rule list

Previous versions of IPFW used separate firewall and accounting entries. The present version provides packet accounting with each firewall entry.

If an index value is supplied, it is used to place the entry at a specific point in the chain. Otherwise, the entry is placed at the end of the chain at an index 100 greater than the last chain entry (this does not include the default policy, rule 65535, deny).

The log option causes matching rules to be output to the system console if the kernel was compiled with IPFIREWALL_VERBOSE.

Valid actions are:

reject

Drop the packet, and send an ICMP host or port unreachable (as appropriate) packet to the source.

allow

Pass the packet on as normal. (aliases: pass, permit, and accept)

deny

Drop the packet. The source is not notified via an ICMP message (thus it appears that the packet never arrived at the destination).

count

Update packet counters but do not allow/deny the packet based on this rule. The search continues with the next chain entry.

Each action will be recognized by the shortest unambiguous prefix.

The protocols which can be specified are:

all

Matches any IP packet

icmp

Matches ICMP packets

tcp

Matches TCP packets

udp

Matches UDP packets

The address specification is:

from address/mask [port] to address/mask [port] [via interface]

You can only specify port in conjunction with protocols which support ports (UDP and TCP).

The via is optional and may specify the IP address or domain name of a local IP interface, or an interface name (e.g. ed0) to match only packets coming through this interface. Interface unit numbers can be specified with an optional wildcard. For example, ppp* would match all kernel PPP interfaces.

The syntax used to specify an address/mask is:

address
or
address/mask-bits
or
address:mask-pattern


A valid hostname may be specified in place of the IP address. mask-bits is a decimal number representing how many bits in the address mask should be set. e.g. specifying 192.216.222.1/24 will create a mask which will allow any address in a class C subnet (in this case, 192.216.222) to be matched. mask-pattern is an IP address which will be logically AND'ed with the address given. The keyword any may be used to specify ``any IP address''.

The port numbers to be blocked are specified as:

port [,port [,port [...]]]

to specify either a single port or a list of ports, or

port-port

to specify a range of ports. You may also combine a single range with a list, but the range must always be specified first.

The options available are:

frag

Matches if the packet is not the first fragment of the datagram.

in

Matches if the packet is on the way in.

out

Matches if the packet is on the way out.

ipoptions spec

Matches if the IP header contains the comma separated list of options specified in spec. The supported IP options are: ssrr (strict source route), lsrr (loose source route), rr (record packet route), and ts (time stamp). The absence of a particular option may be specified with a leading !.

established

Matches if the packet is part of an already established TCP connection (i.e. it has the RST or ACK bits set). You can optimize the performance of the firewall by placing established rules early in the chain.

setup

Matches if the packet is an attempt to establish a TCP connection (the SYN bit is set but the ACK bit is not).

tcpflags flags

Matches if the TCP header contains the comma separated list of flags. The supported flags are fin, syn, rst, psh, ack, and urg. The absence of a particular flag may be indicated by a leading !.

icmptypes types

Matches if the ICMP type is present in the list types. The list may be specified as any combination of ranges and/or individual types separated by commas. Commonly used ICMP types are: 0 echo reply (ping reply), 3 destination unreachable, 5 redirect, 8 echo request (ping request), and 11 time exceeded (used to indicate TTL expiration as with traceroute(8)).


10.8.4.2 Listing the IPFW Rules

The syntax for this form of the command is:

ipfw [-a] [-c] [-d] [-e] [-t] [-N] [-S] list



There are seven valid flags when using this form of the command:

-a

While listing, show counter values. This option is the only way to see accounting counters.

-c

List rules in compact form.

-d

Show dynamic rules in addition to static rules.

-e

If -d was specified, also show expired dynamic rules.

-t

Display the last match times for each chain entry. The time listing is incompatible with the input syntax used by the ipfw(8) utility.

-N

Attempt to resolve given addresses and service names.

-S

Show the set each rule belongs to. If this flag is not specified, disabled rules will not be listed.


10.8.4.3 Flushing the IPFW Rules

The syntax for flushing the chain is:

ipfw flush



This causes all entries in the firewall chain to be removed except the fixed default policy enforced by the kernel (index 65535). Use caution when flushing rules; the default deny policy will leave your system cut off from the network until allow entries are added to the chain.


10.8.4.4 Clearing the IPFW Packet Counters

The syntax for clearing one or more packet counters is:

ipfw zero [index]



When used without an index argument, all packet counters are cleared. If an index is supplied, the clearing operation only affects a specific chain entry.


10.8.5 Example Commands for ipfw

This command will deny all packets from the host evil.crackers.org to the telnet port of the host nice.people.org:

# ipfw add deny tcp from evil.crackers.org to nice.people.org 23

The next example denies and logs any TCP traffic from the entire crackers.org network (a class C) to the nice.people.org machine (any port).

# ipfw add deny log tcp from evil.crackers.org/24 to nice.people.org

If you do not want people sending X sessions to your internal network (a subnet of a class C), the following command will do the necessary filtering:

# ipfw add deny tcp from any to my.org/28 6000 setup

To see the accounting records:

# ipfw -a list
or in the short form
# ipfw -a l


You can also see the last time a chain entry was matched with:

# ipfw -at l

10.8.6 Building a Packet Filtering Firewall

Note: The following suggestions are just that: suggestions. The requirements of each firewall are different and we cannot tell you how to build a firewall to meet your particular requirements.

When initially setting up your firewall, unless you have a test bench setup where you can configure your firewall host in a controlled environment, it is strongly recommend you use the logging version of the commands and enable logging in the kernel. This will allow you to quickly identify problem areas and cure them without too much disruption. Even after the initial setup phase is complete, I recommend using the logging for `deny' as it allows tracing of possible attacks and also modification of the firewall rules if your requirements alter.

Note: If you use the logging versions of the accept command, be aware that it can generate large amounts of log data. One log entry will be generated for every packet that passes through the firewall, so large FTP/http transfers, etc, will really slow the system down. It also increases the latencies on those packets as it requires more work to be done by the kernel before the packet can be passed on. syslogd will also start using up a lot more processor time as it logs all the extra data to disk, and it could quite easily fill the partition /var/log is located on.

You should enable your firewall from /etc/rc.conf.local or /etc/rc.conf. The associated manual page explains which knobs to fiddle and lists some preset firewall configurations. If you do not use a preset configuration, ipfw list will output the current ruleset into a file that you can pass to rc.conf. If you do not use /etc/rc.conf.local or /etc/rc.conf to enable your firewall, it is important to make sure your firewall is enabled before any IP interfaces are configured.

The next problem is what your firewall should actually do! This is largely dependent on what access to your network you want to allow from the outside, and how much access to the outside world you want to allow from the inside. Some general rules are:

  • Block all incoming access to ports below 1024 for TCP. This is where most of the security sensitive services are, like finger, SMTP (mail) and telnet.

  • Block all incoming UDP traffic. There are very few useful services that travel over UDP, and what useful traffic there is, is normally a security threat (e.g. Suns RPC and NFS protocols). This has its disadvantages also, since UDP is a connectionless protocol, denying incoming UDP traffic also blocks the replies to outgoing UDP traffic. This can cause a problem for people (on the inside) using external archie (prospero) servers. If you want to allow access to archie, you will have to allow packets coming from ports 191 and 1525 to any internal UDP port through the firewall. ntp is another service you may consider allowing through, which comes from port 123.

  • Block traffic to port 6000 from the outside. Port 6000 is the port used for access to X11 servers, and can be a security threat (especially if people are in the habit of doing xhost + on their workstations). X11 can actually use a range of ports starting at 6000, the upper limit being how many X displays you can run on the machine. The upper limit as defined by RFC 1700 (Assigned Numbers) is 6063.

  • Check what ports any internal servers use (e.g. SQL servers, etc). It is probably a good idea to block those as well, as they normally fall outside the 1-1024 range specified above.

Another checklist for firewall configuration is available from CERT at http://www.cert.org/tech_tips/packet_filtering.html

As stated above, these are only guidelines. You will have to decide what filter rules you want to use on your firewall yourself. We cannot accept ANY responsibility if someone breaks into your network, even if you follow the advice given above.


10.8.7 IPFW Overhead and Optimization

Many people want to know how much overhead IPFW adds to a system. The answer to this depends mostly on your rule set and processor speed. For most applications dealing with Ethernet and small rule sets, the answer is ``negligible''. For those of you that need actual measurements to satisfy your curiosity, read on.

The following measurements were made using 2.2.5-STABLE on a 486-66. (While IPFW has changed slightly in later releases of FreeBSD, it still performs with similar speed.) IPFW was modified to measure the time spent within the ip_fw_chk routine, displaying the results to the console every 1000 packets.

Two rule sets, each with 1000 rules, were tested. The first set was designed to demonstrate a worst case scenario by repeating the rule:

# ipfw add deny tcp from any to any 55555

This demonstrates a worst case scenario by causing most of IPFW's packet check routine to be executed before finally deciding that the packet does not match the rule (by virtue of the port number). Following the 999th iteration of this rule was an allow ip from any to any.

The second set of rules were designed to abort the rule check quickly:

# ipfw add deny ip from 1.2.3.4 to 1.2.3.4

The non-matching source IP address for the above rule causes these rules to be skipped very quickly. As before, the 1000th rule was an allow ip from any to any.

The per-packet processing overhead in the former case was approximately 2.703 ms/packet, or roughly 2.7 microseconds per rule. Thus the theoretical packet processing limit with these rules is around 370 packets per second. Assuming 10 Mbps Ethernet and a ~1500 byte packet size, we would only be able to achieve 55.5% bandwidth utilization.

For the latter case each packet was processed in approximately 1.172 ms, or roughly 1.2 microseconds per rule. The theoretical packet processing limit here would be about 853 packets per second, which could consume 10 Mbps Ethernet bandwidth.

The excessive number of rules tested and the nature of those rules do not provide a real-world scenario -- they were used only to generate the timing information presented here. Here are a few things to keep in mind when building an efficient rule set:

  • Place an established rule early on to handle the majority of TCP traffic. Do not put any allow tcp statements before this rule.

  • Place heavily triggered rules earlier in the rule set than those rarely used (without changing the permissiveness of the firewall, of course). You can see which rules are used most often by examining the packet counting statistics with ipfw -a l.


10.9 OpenSSL

As of FreeBSD 4.0, the OpenSSL toolkit is a part of the base system. OpenSSL provides a general-purpose cryptography library, as well as the Secure Sockets Layer v2/v3 (SSLv2/SSLv3) and Transport Layer Security v1 (TLSv1) network security protocols.

However, one of the algorithms (specifically IDEA) included in OpenSSL is protected by patents in the USA and elsewhere, and is not available for unrestricted use. IDEA is included in the OpenSSL sources in FreeBSD, but it is not built by default. If you wish to use it, and you comply with the license terms, enable the MAKE_IDEA switch in /etc/make.conf and rebuild your sources using make world.

Today, the RSA algorithm is free for use in USA and other countries. In the past it was protected by a patent.


10.9.1 Source Code Installations

OpenSSL is part of the src-crypto and src-secure CVSup collections. See the Obtaining FreeBSD section for more information about obtaining and updating FreeBSD source code.


10.10 VPN over IPsec

Written by Nik Clayton.

Creating a VPN between two networks, separated by the Internet, using FreeBSD gateways.


10.10.1 Understanding IPsec

Written by Hiten M. Pandya.

This section will guide you through the process of setting up IPsec, and to use it in an environment which consists of FreeBSD and Microsoft Windows 2000/XP machines, to make them communicate securely. In order to set up IPsec, it is necessary that you are familiar with the concepts of building a custom kernel (see Chapter 9).

IPsec is a protocol which sits on top of the Internet Protocol (IP) layer. It allows two or more hosts to communicate in a secure manner (hence the name). The FreeBSD IPsec ``network stack'' is based on the KAME implementation, which has support for both protocol families, IPv4 and IPv6.

Note: FreeBSD 5.X contains a ``hardware accelerated'' IPsec stack, known as ``Fast IPsec'', that was obtained from OpenBSD. It employs cryptographic hardware (whenever possible) via the crypto(4) subsystem to optimize the performance of IPsec. This subsystem is new, and does not support all the features that are available in the KAME version of IPsec. However, in order to enable hardware-accelerated IPsec, the following kernel option has to be added to your kernel configuration file:

options      FAST_IPSEC  # new IPsec (cannot define w/ IPSEC)
       

Note, that it is not currently possible to use the ``Fast IPsec'' subsystem in lue with the KAME implementation of IPsec. Consult the fast_ipsec(4) manual page for more information.

IPsec consists of two sub-protocols:

  • Encapsulated Security Payload (ESP), protects the IP packet data from third party interference, by encrypting the contents using symmetric cryptography algorithms (like Blowfish, 3DES).

  • Authentication Header (AH), protects the IP packet header from third party interference and spoofing, by computing a cryptographic checksum and hashing the IP packet header fields with a secure hashing function. This is then followed by an additional header that contains the hash, to allow the information in the packet to be authenticated.

ESP and AH can either be used together or separately, depending on the environment.

IPsec can either be used to directly encrypt the traffic between two hosts (known as Transport Mode); or to build ``virtual tunnels'' between two subnets, which could be used for secure communication between two corporate networks (known as Tunnel Mode). The latter is more commonly known as a Virtual Private Network (VPN). The ipsec(4) manual page should be consulted for detailed information on the IPsec subsystem in FreeBSD.

To add IPsec support to your kernel, add the following options to your kernel configuration file:

options   IPSEC        #IP security
options   IPSEC_ESP    #IP security (crypto; define w/ IPSEC)
     

If IPsec debugging support is desired, the following kernel option should also be added:

options   IPSEC_DEBUG  #debug for IP security
     

10.10.2 The Problem

There's no standard for what constitutes a VPN. VPNs can be implemented using a number of different technologies, each of which have their own strengths and weaknesses. This article presents a number of scenarios, and strategies for implementing a VPN for each scenario.


10.10.3 Scenario #1: Two networks, connected to the Internet, to behave as one

This is the scenario that caused me to first investigating VPNs. The premise is as follows:

  • You have at least two sites

  • Both sites are using IP internally

  • Both sites are connected to the Internet, through a gateway that is running FreeBSD.

  • The gateway on each network has at least one public IP address.

  • The internal addresses of the two networks can be public or private IP addresses, it doesn't matter. You can be running NAT on the gateway machine if necessary.

  • The internal IP addresses of the two networks do not collide. While I expect it is theoretically possible to use a combination of VPN technology and NAT to get this to work, I expect it to be a configuration nightmare.

If you find that you are trying to connect two networks, both of which, internally, use the same private IP address range (e.g., both of them use 192.168.1.x), then one of the networks will have to be renumbered.

The network topology might look something like this:

Notice the two public IP addresses. I'll use the letters to refer to them in the rest of this article. Anywhere you see those letters in this article, replace them with your own public IP addresses. Note also that that internally, the two gateway machines have .1 IP addresses, and that the two networks have different private IP address (192.168.1.x and 192.168.2.x respectively). All the machines on the private networks have been configured to use the .1 machine as their default gateway.

The intention is that, from a network point of view, each network should view the machines on the other network as though they were directly attached the same router -- albeit a slightly slow router with an occasional tendency to drop packets.

This means that (for example), machine 192.168.1.20 should be able to run

ping 192.168.2.34

and have it work, transparently. Windows machines should be able to see the machines on the other network, browse file shares, and so on, in exactly the same way that they can browse machines on the local network.

And the whole thing has to be secure. This means that traffic between the two networks has to be encrypted.

Creating a VPN between these two networks is a multi-step process. The stages are as follows:

  1. Create a ``virtual'' network link between the two networks, across the Internet. Test it, using tools like ping(8), to make sure it works.

  2. Apply security policies to ensure that traffic between the two networks is transparently encrypted and decrypted as necessary. Test this, using tools like tcpdump(1), to ensure that traffic is encrypted.

  3. Configure additional software on the FreeBSD gateways, to allow Windows machines to see one another across the VPN.


10.10.3.1 Step 1: Creating and testing a ``virtual'' network link

Suppose that you were logged in to the gateway machine on network #1 (with public IP address A.B.C.D, private IP address 192.168.1.1), and you ran ping 192.168.2.1, which is the private address of the machine with IP address W.X.Y.Z. What needs to happen in order for this to work?

  1. The gateway machine needs to know how to reach 192.168.2.1. In other words, it needs to have a route to 192.168.2.1.

  2. Private IP addresses, such as those in the 192.168.x range are not supposed to appear on the Internet at large. Instead, each packet you send to 192.168.2.1 will need to be wrapped up inside another packet. This packet will need to appear to be from A.B.C.D, and it will have to be sent to W.X.Y.Z. This process is called encapsulation.

  3. Once this packet arrives at W.X.Y.Z it will need to ``unencapsulated'', and delivered to 192.168.2.1.

You can think of this as requiring a ``tunnel'' between the two networks. The two ``tunnel mouths'' are the IP addresses A.B.C.D and W.X.Y.Z, and the tunnel must be told the addresses of the private IP addresses that will be allowed to pass through it. The tunnel is used to transfer traffic with private IP addresses across the public Internet.

This tunnel is created by using the generic interface, or gif devices on FreeBSD. As you can imagine, the gif interface on each gateway host must be configured with four IP addresses; two for the public IP addresses, and two for the private IP addresses.

Support for the gif device must be compiled in to the FreeBSD kernel on both machines. You can do this by adding the line:

pseudo-device gif

to the kernel configuration files on both machines, and then compile, install, and reboot as normal.

Configuring the tunnel is a two step process. First the tunnel must be told what the outside (or public) IP addresses are, using gifconfig(8). Then the private IP addresses must be configured using ifconfig(8).

On the gateway machine on network #1 you would run the following two commands to configure the tunnel.

gifconfig gif0 A.B.C.D W.X.Y.Z
ifconfig gif0 inet 192.168.1.1 192.168.2.1 netmask 0xffffffff
     

On the other gateway machine you run the same commands, but with the order of the IP addresses reversed.

gifconfig gif0 W.X.Y.Z A.B.C.D
ifconfig gif0 inet 192.168.2.1 192.168.1.1 netmask 0xffffffff
     

You can then run:

gifconfig gif0

to see the configuration. For example, on the network #1 gateway, you would see this:

# gifconfig gif0
gif0: flags=8011<UP,POINTTOPOINT,MULTICAST> mtu 1280
inet 192.168.1.1 --> 192.168.2.1 netmask 0xffffffff
physical address inet A.B.C.D --> W.X.Y.Z
     

As you can see, a tunnel has been created between the physical addresses A.B.C.D and W.X.Y.Z, and the traffic allowed through the tunnel is that between 192.168.1.1 and 192.168.2.1.

This will also have added an entry to the routing table on both machines, which you can examine with the command netstat -rn. This output is from the gateway host on network #1.

# netstat -rn
Routing tables
 
Internet:
Destination      Gateway       Flags    Refs    Use    Netif  Expire
...
192.168.2.1      192.168.1.1   UH        0        0    gif0
...
     

As the ``Flags'' value indicates, this is a host route, which means that each gateway knows how to reach the other gateway, but they do not know how to reach the rest of their respective networks. That problem will be fixed shortly.

It is likely that you are running a firewall on both machines. This will need to be circumvented for your VPN traffic. You might want to allow all traffic between both networks, or you might want to include firewall rules that protect both ends of the VPN from one another.

It greatly simplifies testing if you configure the firewall to allow all traffic through the VPN. You can always tighten things up later. If you are using ipfw(8) on the gateway machines then a command like

ipfw add 1 allow ip from any to any via gif0

will allow all traffic between the two end points of the VPN, without affecting your other firewall rules. Obviously you will need to run this command on both gateway hosts.

This is sufficient to allow each gateway machine to ping the other. On 192.168.1.1, you should be able to run

ping 192.168.2.1

and get a response, and you should be able to do the same thing on the other gateway machine.

However, you will not be able to reach internal machines on either network yet. This is because of the routing -- although the gateway machines know how to reach one another, they do not know how to reach the network behind each one.

To solve this problem you must add a static route on each gateway machine. The command to do this on the first gateway would be:

route add 192.168.2.0 192.168.2.1 netmask 0xffffff00
     

This says ``In order to reach the hosts on the network 192.168.2.0, send the packets to the host 192.168.2.1''. You will need to run a similar command on the other gateway, but with the 192.168.1.x addresses instead.

IP traffic from hosts on one network will now be able to reach hosts on the other network.

That has now created two thirds of a VPN between the two networks, in as much as it is ``virtual'' and it is a ``network''. It is not private yet. You can test this using ping(8) and tcpdump(1). Log in to the gateway host and run

tcpdump dst host 192.168.2.1

In another log in session on the same host run

ping 192.168.2.1

You will see output that looks something like this:

16:10:24.018080 192.168.1.1 > 192.168.2.1: icmp: echo request
16:10:24.018109 192.168.1.1 > 192.168.2.1: icmp: echo reply
16:10:25.018814 192.168.1.1 > 192.168.2.1: icmp: echo request
16:10:25.018847 192.168.1.1 > 192.168.2.1: icmp: echo reply
16:10:26.028896 192.168.1.1 > 192.168.2.1: icmp: echo request
16:10:26.029112 192.168.1.1 > 192.168.2.1: icmp: echo reply
     

As you can see, the ICMP messages are going back and forth unencrypted. If you had used the -s parameter to tcpdump(1) to grab more bytes of data from the packets you would see more information.

Obviously this is unacceptable. The next section will discuss securing the link between the two networks so that it all traffic is automatically encrypted.

Summary:

  • Configure both kernels with ``pseudo-device gif''.

  • Edit /etc/rc.conf on gateway host #1 and add the following lines (replacing IP addresses as necessary).

    gifconfig_gif0="A.B.C.D W.X.Y.Z"
    ifconfig_gif0="inet 192.168.1.1 192.168.2.1 netmask 0xffffffff"
    static_routes="vpn"
    route_vpn="192.168.2.0 192.168.2.1 netmask 0xffffff00"
             
    
  • Edit your firewall script (/etc/rc.firewall, or similar) on both hosts, and add

    ipfw add 1 allow ip from any to any via gif0
    
  • Make similar changes to /etc/rc.conf on gateway host #2, reversing the order of IP addresses.


10.10.3.2 Step 2: Securing the link

To secure the link we will be using IPsec. IPsec provides a mechanism for two hosts to agree on an encryption key, and to then use this key in order to encrypt data between the two hosts.

The are two areas of configuration to be considered here.

  1. There must be a mechanism for two hosts to agree on the encryption mechanism to use. Once two hosts have agreed on this mechanism there is said to be a ``security association'' between them.

  2. There must be a mechanism for specifying which traffic should be encrypted. Obviously, you don't want to encrypt all your outgoing traffic -- you only want to encrypt the traffic that is part of the VPN. The rules that you put in place to determine what traffic will be encrypted are called ``security policies''.

Security associations and security policies are both maintained by the kernel, and can be modified by userland programs. However, before you can do this you must configure the kernel to support IPsec and the Encapsulated Security Payload (ESP) protocol. This is done by configuring a kernel with:

options IPSEC
options IPSEC_ESP
      

and recompiling, reinstalling, and rebooting. As before you will need to do this to the kernels on both of the gateway hosts.

You have two choices when it comes to setting up security associations. You can configure them by hand between two hosts, which entails choosing the encryption algorithm, encryption keys, and so forth, or you can use daemons that implement the Internet Key Exchange protocol (IKE) to do this for you.

I recommend the latter. Apart from anything else, it is easier to set up.

Editing and displaying security policies is carried out using setkey(8). By analogy, setkey is to the kernel's security policy tables as route(8) is to the kernel's routing tables. setkey can also display the current security associations, and to continue the analogy further, is akin to netstat -r in that respect.

There are a number of choices for daemons to manage security associations with FreeBSD. This article will describe how to use one of these, racoon. racoon is in the FreeBSD ports collection, in the security/ category, and is installed in the usual way.

racoon must be run on both gateway hosts. On each host it is configured with the IP address of the other end of the VPN, and a secret key (which you choose, and must be the same on both gateways).

The two daemons then contact one another, confirm that they are who they say they are (by using the secret key that you configured). The daemons then generate a new secret key, and use this to encrypt the traffic over the VPN. They periodically change this secret, so that even if an attacker were to crack one of the keys (which is as theoretically close to unfeasible as it gets) it won't do them much good -- by the time they've cracked the key the two daemons have chosen another one.

racoon's configuration is stored in ${PREFIX}/etc/racoon. You should find a configuration file there, which should not need to be changed too much. The other component of racoon's configuration, which you will need to change, is the ``pre-shared key''.

The default racoon configuration expects to find this in the file ${PREFIX}/etc/racoon/psk.txt. It is important to note that the pre-shared key is not the key that will be used to encrypt your traffic across the VPN link, it is simply a token that allows the key management daemons to trust one another.

psk.txt contains a line for each remote site you are dealing with. In this example, where there are two sites, each psk.txt file will contain one line (because each end of the VPN is only dealing with one other end).

On gateway host #1 this line should look like this:

W.X.Y.Z            secret

That is, the public IP address of the remote end, whitespace, and a text string that provides the secret. Obviously, you shouldn't use ``secret'' as your key -- the normal rules for choosing a password apply.

On gateway host #2 the line would look like this

A.B.C.D            secret

That is, the public IP address of the remote end, and the same secret key. psk.txt must be mode 0600 (i.e., only read/write to root) before racoon will run.

You must run racoon on both gateway machines. You will also need to add some firewall rules to allow the IKE traffic, which is carried over UDP to the ISAKMP (Internet Security Association Key Management Protocol) port. Again, this should be fairly early in your firewall ruleset.

ipfw add 1 allow udp from A.B.C.D to W.X.Y.Z isakmp
ipfw add 1 allow udp from W.X.Y.Z to A.B.C.D isakmp
      

Once racoon is running you can try pinging one gateway host from the other. The connection is still not encrypted, but racoon will then set up the security associations between the two hosts -- this might take a moment, and you may see this as a short delay before the ping commands start responding.

Once the security association has been set up you can view it using setkey(8). Run

setkey -D

on either host to view the security association information.

That's one half of the problem. They other half is setting your security policies.

To create a sensible security policy, let's review what's been set up so far. This discussions hold for both ends of the link.

Each IP packet that you send out has a header that contains data about the packet. The header includes the IP addresses of both the source and destination. As we already know, private IP addresses, such as the 192.168.x.y range are not supposed to appear on the public Internet. Instead, they must first be encapsulated inside another packet. This packet must have the public source and destination IP addresses substituted for the private addresses.

So if your outgoing packet started looking like this:

Then it will be encapsulated inside another packet, looking something like this:

This encapsulation is carried out by the gif device. As you can see, the packet now has real IP addresses on the outside, and our original packet has been wrapped up as data inside the packet that will be put out on the Internet.

Obviously, we want all traffic between the VPNs to be encrypted. You might try putting this in to words, as:

``If a packet leaves from A.B.C.D, and it is destined for W.X.Y.Z, then encrypt it, using the necessary security associations.''

``If a packet arrives from W.X.Y.Z, and it is destined for A.B.C.D, then decrypt it, using the necessary security associations.''

That's close, but not quite right. If you did this, all traffic to and from W.X.Y.Z, even traffic that was not part of the VPN, would be encrypted. That's not quite what you want. The correct policy is as follows

``If a packet leaves from A.B.C.D, and that packet is encapsulating another packet, and it is destined for W.X.Y.Z, then encrypt it, using the necessary security associations.''

``If a packet arrives from W.X.Y.Z, and that packet is encapsulating another packet, and it is destined for A.B.C.D, then encrypt it, using the necessary security associations.''

A subtle change, but a necessary one.

Security policies are also set using setkey(8). setkey(8) features a configuration language for defining the policy. You can either enter configuration instructions via stdin, or you can use the -f option to specify a filename that contains configuration instructions.

The configuration on gateway host #1 (which has the public IP address A.B.C.D) to force all outbound traffic to W.X.Y.Z to be encrypted is:

spdadd A.B.C.D/32 W.X.Y.Z/32 ipencap -P out ipsec esp/tunnel/A.B.C.D-W.X.Y.Z/require;
      

Put these commands in a file (e.g., /etc/ipsec.conf) and then run

# setkey -f /etc/ipsec.conf

spdadd tells setkey(8) that we want to add a rule to the secure policy database. The rest of this line specifies which packets will match this policy. A.B.C.D/32 and W.X.Y.Z/32 are the IP addresses and netmasks that identify the network or hosts that this policy will apply to. In this case, we want it to apply to traffic between these two hosts. ipencap tells the kernel that this policy should only apply to packets that encapsulate other packets. -P out says that this policy applies to outgoing packets, and ipsec says that the packet will be secured.

The second line specifies how this packet will be encrypted. esp is the protocol that will be used, while tunnel indicates that the packet will be further encapsulated in an IPsec packet. The repeated use of A.B.C.D and W.X.Y.Z is used to select the security association to use, and the final require mandates that packets must be encrypted if they match this rule.

This rule only matches outgoing packets. You will need a similar rule to match incoming packets.

spdadd W.X.Y.Z/32 A.B.C.D/32 ipencap -P in ipsec esp/tunnel/W.X.Y.Z-A.B.C.D/require;

Note the in instead of out in this case, and the necessary reversal of the IP addresses.

The other gateway host (which has the public IP address W.X.Y.Z) will need similar rules.

spdadd W.X.Y.Z/32 A.B.C.D/32 ipencap -P out ipsec esp/tunnel/W.X.Y.Z-A.B.C.D/require;
       spdadd A.B.C.D/32 W.X.Y.Z/32 ipencap -P in ipsec esp/tunnel/A.B.C.D-W.X.Y.Z/require;

Finally, you need to add firewall rules to allow ESP and IPENCAP packets back and forth. These rules will need to be added to both hosts.

ipfw add 1 allow esp from A.B.C.D to W.X.Y.Z
ipfw add 1 allow esp from W.X.Y.Z to A.B.C.D
ipfw add 1 allow ipencap from A.B.C.D to W.X.Y.Z
ipfw add 1 allow ipencap from W.X.Y.Z to A.B.C.D
      

Because the rules are symmetric you can use the same rules on each gateway host.

Outgoing packets will now look something like this:

When they are received by the far end of the VPN they will first be decrypted (using the security associations that have been negotiated by racoon). Then they will enter the gif interface, which will unwrap the second layer, until you are left with the innermost packet, which can then travel in to the inner network.

You can check the security using the same ping(8) test from earlier. First, log in to the A.B.C.D gateway machine, and run:

tcpdump dst host 192.168.2.1

In another log in session on the same host run

ping 192.168.2.1

This time you should see output like the following:

XXX tcpdump output

Now, as you can see, tcpdump(1) shows the ESP packets. If you try and examine them with the -s option you will see (apparently) gibberish, because of the encryption.

Congratulations. You have just set up a VPN between two remote sites.

Summary

  • Configure both kernels with:

    options IPSEC
    options IPSEC_ESP
             
    
  • Install security/racoon. Edit ${PREFIX}/etc/racoon/psk.txt on both gateway hosts, adding an entry for the remote host's IP address and a secret key that they both know. Make sure this file is mode 0600.

  • Add the following lines to /etc/rc.conf on each host:

    ipsec_enable="YES"
    ipsec_file="/etc/ipsec.conf"
             
    
  • Create an /etc/ipsec.conf on each host that contains the necessary spdadd lines. On gateway host #1 this would be:

    spdadd A.B.C.D/32 W.X.Y.Z/32 ipencap -P out ipsec
      esp/tunnel/A.B.C.D-W.X.Y.Z/require;
    spdadd W.X.Y.Z/32 A.B.C.D/32 ipencap -P in ipsec
      esp/tunnel/W.X.Y.Z-A.B.C.D/require;
    

    On gateway host #2 this would be:

    spdadd W.X.Y.Z/32 A.B.C.D/32 ipencap -P out ipsec
      esp/tunnel/W.X.Y.Z-A.B.C.D/require;
    spdadd A.B.C.D/32 W.X.Y.Z/32 ipencap -P in ipsec
      esp/tunnel/A.B.C.D-W.X.Y.Z/require;
    
  • Add firewall rules to allow IKE, ESP, and IPENCAP traffic to both hosts:

    ipfw add 1 allow udp from A.B.C.D to W.X.Y.Z isakmp
    ipfw add 1 allow udp from W.X.Y.Z to A.B.C.D isakmp
    ipfw add 1 allow esp from A.B.C.D to W.X.Y.Z
    ipfw add 1 allow esp from W.X.Y.Z to A.B.C.D
    ipfw add 1 allow ipencap from A.B.C.D to W.X.Y.Z
    ipfw add 1 allow ipencap from W.X.Y.Z to A.B.C.D
             
    

The previous two steps should suffice to get the VPN up and running. Machines on each network will be able to refer to one another using IP addresses, and all traffic across the link will be automatically and securely encrypted.


10.11 OpenSSH

Contributed by Chern Lee.

OpenSSH is a set of network connectivity tools used to access remote machines securely. It can be used as a direct replacement for rlogin, rsh, rcp, and telnet. Additionally, any other TCP/IP connections can be tunneled/forwarded securely through SSH. OpenSSH encrypts all traffic to effectively eliminate eavesdropping, connection hijacking, and other network-level attacks.

OpenSSH is maintained by the OpenBSD project, and is based upon SSH v1.2.12 with all the recent bug fixes and updates. It is compatible with both SSH protocols 1 and 2. OpenSSH has been in the base system since FreeBSD 4.0.


10.11.1 Advantages of Using OpenSSH

Normally, when using telnet(1) or rlogin(1), data is sent over the network in an clear, un-encrypted form. Network sniffers anywhere in between the client and server can steal your user/password information or data transferred in your session. OpenSSH offers a variety of authentication and encryption methods to prevent this from happening.


10.11.2 Enabling sshd

Be sure to make the following addition to your rc.conf file:

sshd_enable="YES"

This will load sshd(8), the daemon program for OpenSSH, the next time your system initializes. Alternatively, you can simply run directly the sshd daemon by typing sshd on the command line.


10.11.3 SSH Client

The ssh(1) utility works similarly to rlogin(1).

# ssh user@example.com
Host key not found from the list of known hosts.
Are you sure you want to continue connecting (yes/no)? yes
Host 'example.com' added to the list of known hosts.
user@example.com's password: *******

The login will continue just as it would have if a session was created using rlogin or telnet. SSH utilizes a key fingerprint system for verifying the authenticity of the server when the client connects. The user is prompted to enter yes only when connecting for the first time. Future attempts to login are all verified against the saved fingerprint key. The SSH client will alert you if the saved fingerprint differs from the received fingerprint on future login attempts. The fingerprints are saved in ~/.ssh/known_hosts, or ~/.ssh/known_hosts2 for SSH v2 fingerprints.

By default, OpenSSH servers are configured to accept both SSH v1 and SSH v2 connections. The client, however, can choose between the two. Version 2 is known to be more robust and secure than its predecessor.

The ssh(1) command can be forced to use either protocol by passing it the -1 or -2 argument for v1 and v2, respectively.


10.11.4 Secure Copy

The scp(1) command works similarly to rcp(1); it copies a file to or from a remote machine, except in a secure fashion.

# scp user@example.com:/COPYRIGHT COPYRIGHT
user@example.com's password: *******
COPYRIGHT            100% |*****************************|  4735       
00:00    
#

Since the fingerprint was already saved for this host in the previous example, it is verified when using scp(1) here.

The arguments passed to scp(1) are similar to cp(1), with the file or files in the first argument, and the destination in the second. Since the file is fetched over the network, through SSH, one or more of the file arguments takes on the form user@host:<path_to_remote_file>.


10.11.5 Configuration

The system-wide configuration files for both the OpenSSH daemon and client reside within the /etc/ssh directory.

ssh_config configures the client settings, while sshd_config configures the daemon.

Additionally, the sshd_program (/usr/sbin/sshd by default), and sshd_flags rc.conf options can provide more levels of configuration.


10.11.6 ssh-keygen

Instead of using passwords, ssh-keygen(1) can be used to generate RSA keys to authenticate a user:

% ssh-keygen -t rsa1
Initializing random number generator...
Generating p:  .++ (distance 66)
Generating q:  ..............................++ (distance 498)
Computing the keys...
Key generation complete.
Enter file in which to save the key (/home/user/.ssh/identity):
Enter passphrase:
Enter the same passphrase again:
Your identification has been saved in /home/user/.ssh/identity.
...

ssh-keygen(1) will create a public and private key pair for use in authentication. The private key is stored in ~/.ssh/identity, whereas the public key is stored in ~/.ssh/identity.pub. The public key must be placed in ~/.ssh/authorized_keys of the remote machine in order for the setup to work.

This will allow connection to the remote machine based upon RSA authentication instead of passwords.

Note: The -t rsa1 option will create RSA keys for use by SSH protocol version 1. If you want to use RSA keys with the SSH protocol version 2, you have to use the command ssh-keygen -t rsa.

If a passphrase is used in ssh-keygen(1), the user will be prompted for a password each time in order to use the private key.

A SSH protocol version 2 DSA key can be created for the same purpose by using the ssh-keygen -t dsa command. This will create a public/private DSA key for use in SSH protocol version 2 sessions only. The public key is stored in ~/.ssh/id_dsa.pub, while the private key is in ~/.ssh/id_dsa.

DSA public keys are also placed in ~/.ssh/authorized_keys on the remote machine.

ssh-agent(1) and ssh-add(1) are utilities used in managing multiple passworded private keys.

Warning: The various options and files can be different according to the OpenSSH version you have on your system, to avoid problems you should consult the ssh-keygen(1) manual page.


10.11.7 SSH Tunneling

OpenSSH has the ability to create a tunnel to encapsulate another protocol in an encrypted session.

The following command tells ssh(1) to create a tunnel for telnet:

% ssh -2 -N -f -L 5023:localhost:23 user@foo.example.com
%

The ssh command is used with the following options:

-2

Forces ssh to use version 2 of the protocol. (Do not use if you are working with older SSH servers)

-N

Indicates no command, or tunnel only. If omitted, ssh would initiate a normal session.

-f

Forces ssh to run in the background.

-L

Indicates a local tunnel in localport:remotehost:remoteport fashion.

user@foo.example.com

The remote SSH server.

An SSH tunnel works by creating a listen socket on localhost on the specified port. It then forwards any connection received on the local host/port via the SSH connection to the specified remote host and port.

In the example, port 5023 on localhost is being forwarded to port 23 on localhost of the remote machine. Since 23 is telnet, this would create a secure telnet session through an SSH tunnel.

This can be used to wrap any number of insecure TCP protocols such as SMTP, POP3, FTP, etc.

Example 10-1. Using SSH to Create a Secure Tunnel for SMTP

% ssh -2 -N -f -L 5025:localhost:25 user@mailserver.example.com
user@mailserver.example.com's password: *****
% telnet localhost 5025
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 mailserver.example.com ESMTP

This can be used in conjunction with an ssh-keygen(1) and additional user accounts to create a more seamless/hassle-free SSH tunneling environment. Keys can be used in place of typing a password, and the tunnels can be run as a separate user.


10.11.7.1 Practical SSH Tunneling Examples

10.11.7.1.1 Secure Access of a POP3 Server

At work, there is an SSH server that accepts connections from the outside. On the same office network resides a mail server running a POP3 server. The network, or network path between your home and office may or may not be completely trustable. Because of this, you need to check your e-mail in a secure manner. The solution is to create an SSH connection to your office's SSH server, and tunnel through to the mail server.

% ssh -2 -N -f -L 2110:mail.example.com:110 user@ssh-server.example.com
user@ssh-server.example.com's password: ******

When the tunnel is up and running, you can point your mail client to send POP3 requests to localhost port 2110. A connection here will be forwarded securely across the tunnel to mail.example.com.


10.11.7.1.2 Bypassing a Draconian Firewall

Some network administrators impose extremely draconian firewall rules, filtering not only incoming connections, but outgoing connections. You may be only given access to contact remote machines on ports 22 and 80 for SSH and web surfing.

You may wish to access another (perhaps non-work related) service, such as an Ogg Vorbis server to stream music. If this Ogg Vorbis server is streaming on some other port than 22 or 80, you will not be able to access it.

The solution is to create an SSH connection to a machine outside of your network's firewall, and use it to tunnel to the Ogg Vorbis server.

% ssh -2 -N -f -L 8888:music.example.com:8000 user@unfirewalled-system.example.org
user@unfirewalled-system.example.org's password: *******

Your streaming client can now be pointed to localhost port 8888, which will be forwarded over to music.example.com port 8000, successfully evading the firewall.


10.12 Mandatory Access Control (MAC)

Sponsored by DARPA and Network Associates Laboratories. Contributed by Robert Watson.

FreeBSD 5.0 includes a new kernel security framework, the TrustedBSD MAC Framework. The MAC Framework permits compile-time, boot-time, and run-time extension of the kernel access control policy, and can be used to load support for Mandatory Access Control (MAC), and custom security modules such as hardening modules. The MAC Framework is currently considered to be an experimental feature, and should not yet be used in production environments without careful consideration. It is anticipated that the MAC Framework will be appropriate for more widespread production use by FreeBSD 5.2.

When configured into a kernel, the MAC Framework permits security modules to augment the existing kernel access control model, restricting access to system services and objects. For example, the mac_bsdextended(4) module augments file system access control, permitting administrators to provide a firewall-like ruleset constraining access to file system objects based on user ids and group membership. Some modules require little or no configuration, such as mac_seeotheruids(4), whereas others perform ubiquitous object labeling, such as mac_biba(4) and mac_mls(4), and require extensive configuration.

To enable the MAC Framework in your system kernel, you must add the following entry to your kernel configuration:

options MAC

Security policy modules shipped with the base system may be loaded using kldload(8) or in the boot loader(8) They may also be compiled directly into the kernel using the following options, if the use of modules is not desired.

Different MAC policies may be configured in different ways; frequently, MAC policy modules export configuration parameters using the sysctl(8) MIB using the security.mac namespace. Policies relying on file system or other labels may require a configuration step that involves assigning initial labels to system objects or creating a policy configuration file. For information on how to configure and use each policy module, see its man page.

A variety of tools are available to configure the MAC Framework and labels maintained by various policies. Extensions have been made to the login and credential management mechanisms (setusercontext(3)) to support initial user labeling using login.conf(5). In addition, modifications have been made to su(1), ps(1), ls(1), and ifconfig(8) to inspect and set labels on processes, files, and interfaces. In addition, several new tools have been added to manage labels on objects, including getfmac(8), setfmac(8), and setfsmac(8) to manage labels on files, and getpmac(8) and setpmac(8).

What follows is a list of policy modules shipped with FreeBSD 5.0.


10.12.1 Biba Integrity Policy (mac_biba)

Vendor: TrustedBSD Project

Module name: mac_biba.ko

Kernel option: MAC_BIBA

The Biba Integrity Policy (mac_biba(4)) provides for hierarchical and non-hierarchical labeling of all system objects with integrity data, and the strict enforcement of an information flow policy to prevent corruption of high integrity subjects and data by low-integrity subjects. Integrity is enforced by preventing high integrity subjects (generally processes) from reading low integrity objects (often files), and preventing low integrity subjects from writing to high integrity objects. This security policy is frequently used in commercial trusted systems to provide strong protection for the Trusted Code Base (TCB). Because it provides ubiquitous labeling, the Biba integrity policy must be compiled into the kernel or loaded at boot.


10.12.2 File System Firewall Policy (mac_bsdextended)

Vendor: TrustedBSD Project

Module name: mac_bsdextended.ko

Kernel option: MAC_BSDEXTENDED

The File System Firewall Policy (mac_bsdextended(4)) provides an extension to the BSD file system permission model, permitting the administrator to define a set of firewall-like rules for limiting access to file system objects owned by other users and groups. Managed using ugidfw(8), rules may limit access to files and directories based on the uid and gids of the process attempting the access, and the owner and group of the target of the access attempt. All rules are restrictive, so they may be placed in any order. This policy requires no prior configuration or labeling, and may be appropriate in multi-user environments where mandatory limits on inter-user data exchange are required. Caution should be exercised in limiting access to files owned by the super-user or other system user ids, as many useful programs and directories are owned by these users. As with a network firewall, improper application of file system firewall rules may render the system unusable. New tools to manage the rule set may be easily written using the libugidfw(3) library.


10.12.3 Interface Silencing Policy (mac_ifoff)

Vendor: TrustedBSD Project

Module name: mac_ifoff.ko

Kernel option: MAC_IFOFF

The interface silencing policy (mac_ifoff(4)) prohibits the use of network interfaces during the boot until explicitly enabled, preventing spurious stack output stack response to incoming packets. This is appropriate for use in environments where the monitoring of packets is required, but no traffic may be generated.


10.12.4 Low-Watermark Mandatory Access Control (LOMAC) (mac_lomac)

Vendor: Network Associates Laboratories

Module name: mac_lomac.ko

Kernel option: MAC_LOMAC

Similar to the Biba Integrity Policy, the LOMAC policy (mac_lomac(4)) relies on the ubiquitous labeling of all system objects with integrity labels. Unlike Biba, LOMAC permits high integrity subjects to read from low integrity objects, but then downgrades the label on the subject to prevent future writes to high integrity objects. This policy may provide for greater compatibility, as well as require less initial configuration than Biba. However, as with Biba, it ubiquitously labels objects and must therefore be compiled into the kernel or loaded at boot.


10.12.5 Multi-Level Security Policy (MLS) (mac_mls)

Vendor: TrustedBSD Project

Module name: mac_mls.ko

Kernel option: MAC_MLS

Multi-Level Security (MLS) (mac_mls(4)) provides for hierarchical and non-hierarchical labeling of all system objects with sensitivity data, and the strict enforcement of an information flow policy to prevent the leakage of confidential data to untrusted parties. The logical conjugate of the Biba Integrity Policy, MLS is frequently shipped in commercial trusted operating systems to protect data secrecy in multi-user environments. Hierarchal labels provide support for the notion of clearances and classifications in traditional parlance; non-hierarchical labels provide support for ``need-to-know.'' As with Biba, ubiquitous labeling of objects occurs, and it must therefore be compiled into the kernel or loaded at boot. As with Biba, extensive initial configuration may be required.


10.12.6 MAC Stub Policy (mac_none)

Vendor: TrustedBSD Project

Module name: mac_none.ko

Kernel option: MAC_NONE

The None policy (mac_none(4)) provides a stub sample policy for developers, implementing all entry points, but not changing the system access control policy. Running this on a production system would not be highly beneficial.


10.12.7 Process Partition Policy (mac_partition)

Vendor: TrustedBSD Project

Module name: mac_partition.ko

Kernel option: MAC_PARTITION

The Partition policy (mac_partition(4)) provides for a simple process visibility limitation, assigning labels to processes identifying what numeric system partition they are present in. If none, all other processes are visible using standard monitoring tools; if a partition identifier is present, then only other processes in the same partition are visible. This policy may be compiled into the kernel, loaded at boot, or loaded at run-time.


10.12.8 See Other Uids Policy (mac_seeotheruids)

Vendor: TrustedBSD Project

Module name: mac_seeotheruids.ko

Kernel option: MAC_SEEOTHERUIDS

The See Other Uids policy (mac_seeotheruids(4)) implements a similar process visibility model to mac_partition, except that it relies on process credentials to control visibility of processes, rather than partition labels. This policy may be configured to exempt certain users and groups, including permitting system operators to view all processes without special privilege. This policy may be compiled into the kernel, loaded at boot, or loaded at run-time.


10.12.9 MAC Framework Test Policy (mac_test)

Vendor: TrustedBSD Project

Module name: mac_test.ko

Kernel option: MAC_TEST

The Test policy (mac_test(4)) provides a regression test environment for the MAC Framework, and will cause a fail-stop in the event that internal MAC Framework assertions about proper data labeling fail. This module can be used to detect failures to properly label system objects in the kernel implementation. This policy may be compiled into the kernel, loaded at boot, or loaded at run-time.


10.13 File System Access Control Lists

Contributed by Tom Rhodes.

In conjunction with file system enhancements like snapshots, FreeBSD 5.0 and later offers the security of File System Access Control Lists (ACLs).

Access Control Lists extend the standard UNIX permission model in a highly compatible (POSIX.1e) way. This feature permits an administrator to make use of and take advantage of a more sophisticated security model.

To enable ACL support for UFS file systems, the following:

options UFS_ACL

must be compiled into the kernel. If this option has not been compiled in, a warning message will be displayed when attempting to mount a file system supporting ACLs. This option is included in the GENERIC kernel. ACLs rely on extended attributes being enabled on the file system. Extended attributes are natively supported in the next generation UNIX file system, UFS2.

Note: A higher level of administrative overhead is required to configure extended attributes on UFS1 than on UFS2. The performance of extended attributes on UFS2 is also substantially higher. As a result, UFS2 is generally recommended in preference to UFS1 for use with access control lists.

ACLs are enabled by the mount-time administrative flag, acls, which may be added to /etc/fstab. The mount-time flag can also be automatically set in a persistent manner using tunefs(8) to modify a superblock ACLs flag in the file system header. In general, it is preferred to use the superblock flag for several reasons:

  • The mount-time ACLs flag cannot be changed by a remount (mount(8) -u), only by means of a complete umount(8) and fresh mount(8). This means that ACLs cannot be enabled on the root file system after boot. It also means that you cannot change the disposition of a file system once it is in use.

  • Setting the superblock flag will cause the file system to always be mounted with ACLs enabled even if there is not an fstab entry or if the devices re-order. This prevents accidental mounting of the file system without ACLs enabled, which can result in ACLs being improperly enforced, and hence security problems.

Note: We may change the ACLs behavior to allow the flag to be enabled without a complete fresh mount(8), but we consider it desirable to discourage accidental mounting without ACLs enabled, because you can shoot your feet quite nastily if you enable ACLs, then disable them, then re-enable them without flushing the extended attributes. In general, once you have enabled ACLs on a file system, they should not be disabled, as the resulting file protections may not be compatible with those intended by the users of the system, and re-enabling ACLs may re-attach the previous ACLs to files that have since had their permissions changed, resulting in other unpredictable behavior.

File systems with ACLs enabled will show a + (plus) sign in their permission settings when viewed. For example:

drwx------  2 robert  robert  512 Dec 27 11:54 private
drwxrwx---+ 2 robert  robert  512 Dec 23 10:57 directory1
drwxrwx---+ 2 robert  robert  512 Dec 22 10:20 directory2
drwxrwx---+ 2 robert  robert  512 Dec 27 11:57 directory3
drwxr-xr-x  2 robert  robert  512 Nov 10 11:54 public_html

Here we see that the directory1, directory2, and directory3 directories are all taking advantage of ACLs. The public_html directory is not.


10.13.1 Making Use of ACLs

The file system ACLs can be viewed by the getfacl(1) utility. For instance, to view the ACL settings on the test file, one would use the command:

% getfacl test
    #file:test
    #owner:1001
    #group:1001
    user::rw-
    group::r--
    other::r--

To change the ACL settings on this file, invoke the setfacl(1) utility. Observe:

% setfacl -k test

The -k flag will remove all of the currently defined ACLs from a file or file system. The more preferable method would be to use -b as it leaves the basic fields required for ACLs to work.

% setfacl -m u:trhodes:rwx,group:web:r--,o::--- test

In the aforementioned command, the -m option was used to modify the default ACL entries. Since there were no pre-defined entries, as they were removed by the previous command, this will restore the default options and assign the options listed. Take care to notice that if you add a user or group which does not exist on the system, an ``Invalid argument'' error will be printed to stdout.


10.14 FreeBSD Security Advisories

Contributed by Tom Rhodes.

Like many production quality operating systems, FreeBSD publishes ``Security Advisories''. These advisories are usually mailed to the security lists and noted in the Errata only after the appropriate releases have been patched. This section will work to explain what an advisory is, how to understand it, and what measures to take in order to patch a system.


10.14.1 What does an advisory look like?

The FreeBSD security advisories look similar to the one below, taken from the freebsd-security-notifications mailing list.

=============================================================================
FreeBSD-SA-XX:XX.UTIL                                     Security Advisory
                                                          The FreeBSD Project

Topic:          denial of service due to some problem(1)

Category:       core(2)
Module:         sys(3)
Announced:      2003-09-23(4)
Credits:        Person@EMAIL-ADDRESS(5)
Affects:        All releases of FreeBSD(6)
                FreeBSD 4-STABLE prior to the correction date
Corrected:      2003-09-23 16:42:59 UTC (RELENG_4, 4.9-PRERELEASE)
                2003-09-23 20:08:42 UTC (RELENG_5_1, 5.1-RELEASE-p6)
                2003-09-23 20:07:06 UTC (RELENG_5_0, 5.0-RELEASE-p15)
                2003-09-23 16:44:58 UTC (RELENG_4_8, 4.8-RELEASE-p8)
                2003-09-23 16:47:34 UTC (RELENG_4_7, 4.7-RELEASE-p18)
                2003-09-23 16:49:46 UTC (RELENG_4_6, 4.6-RELEASE-p21)
                2003-09-23 16:51:24 UTC (RELENG_4_5, 4.5-RELEASE-p33)
                2003-09-23 16:52:45 UTC (RELENG_4_4, 4.4-RELEASE-p43)
                2003-09-23 16:54:39 UTC (RELENG_4_3, 4.3-RELEASE-p39)(7)
FreeBSD only:   NO(8)

For general information regarding FreeBSD Security Advisories,
including descriptions of the fields above, security branches, and the
following sections, please visit
http://www.freebsd.org/security/.

I.   Background(9)


II.  Problem Description(10)


III. Impact(11)


IV.  Workaround(12)


V.   Solution(13)


VI.  Correction details(14)


VII. References(15)
(1)
The Topic field indicates exactly what the problem is. It is basically an introduction to the current security advisory and notes the utility with the vulnerability.
(2)
The Category refers to the affected part of the system which may be one of core, contrib, or ports. The core category means that the vulnerability affects a core component of the FreeBSD operating system. The contrib category means that the vulnerability affects software contributed to the FreeBSD Project, such as sendmail. Finally the ports category indicates that the vulnerability affects add on software available as part of the ports collection.
(3)
The Module field refers to the component location, for instance sys. In this example, we see that the module, sys, is affected; therefore, this vulnerability affects a component used within the kernel.
(4)
The Announced field reflects the date said security advisory was published, or announced to the world. This means that the security team has verified that the problem does exist and that a patch has been committed to the FreeBSD source code repository.
(5)
The Credits field gives credit to the individual or organization who noticed the vulnerability and reported it.
(6)
The Affects field explains which releases of FreeBSD are affected by this vulnerability. For the kernel, a quick look over the output from ident on the affected files will help in determining the revision. For ports, the version number is listed after the port name in /var/db/pkg. If the system does not sync with the FreeBSD CVS repository and rebuild daily, chances are that it is affected.
(7)
The Corrected field indicates the date, time, time offset, and release that was corrected.
(8)
The FreeBSD only field indicates whether this vulnerability affects just FreeBSD, or if it affects other operating systems as well.
(9)
The Background field gives information on exactly what the affected utility is. Most of the time this is why the utility exists in FreeBSD, what it is used for, and a bit of information on how the utility came to be.
(10)
The Problem Description field explains the security hole in depth. This can include information on flawed code, or even how the utility could be maliciously used to open a security hole.
(11)
The Impact field describes what type of impact the problem could have on a system. For example, this could be anything from a denial of service attack, to extra privileges available to users, or even giving the attacker superuser access.
(12)
The Workaround field offers a feasible workaround to system administrators who may be incapable of upgrading the system. This may be due to time constraints, network availability, or a slew of other reasons. Regardless, security should not be taken lightly, and an affected system should either be patched or the security hole workaround should be implemented.
(13)
The Solution field offers instructions on patching the affected system. This is a step by step tested and verified method for getting a system patched and working securely.
(14)
The Correction Details field displays the CVS branch or release name with the periods changed to underscore characters. It also shows the revision number of the affected files within each branch.
(15)
The References field usually offers sources of other information. This can included web URLs, books, mailing lists, and newsgroups.

Chapter 11 Printing

Contributed by Sean Kelly. Restructured and updated by Jim Mock.

11.1 Synopsis

FreeBSD can be used to print to a wide variety of printers, from the oldest impact printer to the latest laser printers, and everything in between, allowing you to produce high quality printed output from the applications you run.

FreeBSD can also be configured to act as a print server on a network; in this capacity FreeBSD can receive print jobs from a variety of other computers, including other FreeBSD computers, Windows and Mac OS hosts. FreeBSD will ensure that one job at a time is printed, and can keep statistics on which users and machines are doing the most printing, produce ``banner'' pages showing who's printout is who's, and more.

After reading this chapter, you will know:

  • How to configure the FreeBSD print spooler.

  • How to install print filters, to handle special print jobs differently, including converting incoming documents to print formats that your printers understand.

  • How to enable header, or banner pages on your printout.

  • How to print to printers connected to other computers.

  • How to print to printers connected directly to the network.

  • How to control printer restrictions, including limiting the size of print jobs, and preventing certain users from printing.

  • How to keep printer statistics, and account for printer usage.

  • How to troubleshoot printing problems.

Before reading this chapter, you should:

  • Know how to configure and install a new kernel (Chapter 9).


11.2 Introduction

In order to use printers with FreeBSD, you will need to set them up to work with the Berkeley line printer spooling system, also known as the LPD spooling system. It is the standard printer control system in FreeBSD. This chapter introduces the LPD spooling system, often simply called LPD, and will guide you through its configuration.

If you are already familiar with LPD or another printer spooling system, you may wish to skip to section Setting up the spooling system.

LPD controls everything about a host's printers. It is responsible for a number of things:

  • It controls access to attached printers and printers attached to other hosts on the network.

  • It enables users to submit files to be printed; these submissions are known as jobs.

  • It prevents multiple users from accessing a printer at the same time by maintaining a queue for each printer.

  • It can print header pages (also known as banner or burst pages) so users can easily find jobs they have printed in a stack of printouts.

  • It takes care of communications parameters for printers connected on serial ports.

  • It can send jobs over the network to a LPD spooler on another host.

  • It can run special filters to format jobs to be printed for various printer languages or printer capabilities.

  • It can account for printer usage.

Through a configuration file (/etc/printcap), and by providing the special filter programs, you can enable the LPD system to do all or some subset of the above for a great variety of printer hardware.


11.2.1 Why You Should Use the Spooler

If you are the sole user of your system, you may be wondering why you should bother with the spooler when you do not need access control, header pages, or printer accounting. While it is possible to enable direct access to a printer, you should use the spooler anyway since:

  • LPD prints jobs in the background; you do not have to wait for data to be copied to the printer.

  • LPD can conveniently run a job to be printed through filters to add date/time headers or convert a special file format (such as a TeX DVI file) into a format the printer will understand. You will not have to do these steps manually.

  • Many free and commercial programs that provide a print feature usually expect to talk to the spooler on your system. By setting up the spooling system, you will more easily support other software you may later add or already have.


11.3 Basic Setup

To use printers with the LPD spooling system, you will need to set up both your printer hardware and the LPD software. This document describes two levels of setup:

  • See section Simple Printer Setup to learn how to connect a printer, tell LPD how to communicate with it, and print plain text files to the printer.

  • See section Advanced Printer Setup to find out how to print a variety of special file formats, to print header pages, to print across a network, to control access to printers, and to do printer accounting.


11.3.1 Simple Printer Setup

This section tells how to configure printer hardware and the LPD software to use the printer. It teaches the basics:

  • Section Hardware Setup gives some hints on connecting the printer to a port on your computer.

  • Section Software Setup shows how to set up the LPD spooler configuration file (/etc/printcap).

If you are setting up a printer that uses a network protocol to accept data to print instead of a serial or parallel interface, see Printers With Networked Data Stream Interfaces.

Although this section is called ``Simple Printer Setup'', it is actually fairly complex. Getting the printer to work with your computer and the LPD spooler is the hardest part. The advanced options like header pages and accounting are fairly easy once you get the printer working.


11.3.1.1 Hardware Setup

This section tells about the various ways you can connect a printer to your PC. It talks about the kinds of ports and cables, and also the kernel configuration you may need to enable FreeBSD to speak to the printer.

If you have already connected your printer and have successfully printed with it under another operating system, you can probably skip to section Software Setup.


11.3.1.1.1 Ports and Cables

Nearly all printers you can get for a PC today support one or both of the following interfaces:

  • Serial interfaces use a serial port on your computer to send data to the printer. Serial interfaces are common in the computer industry and cables are readily available and also easy to construct. Serial interfaces sometimes need special cables and might require you to configure somewhat complex communications options.

  • Parallel interfaces use a parallel port on your computer to send data to the printer. Parallel interfaces are common in the PC market. Cables are readily available but more difficult to construct by hand. There are usually no communications options with parallel interfaces, making their configuration exceedingly simple.

    Parallel interfaces are sometimes known as ``Centronics'' interfaces, named after the connector type on the printer.

In general, serial interfaces are slower than parallel interfaces. Parallel interfaces usually offer just one-way communication (computer to printer) while serial gives you two-way. Newer parallel ports (EPP and ECP) and printers can communicate in both directions under FreeBSD when a IEEE1284 compliant cable is used.

Usually, the only time you need two-way communication with the printer is if the printer speaks PostScript. PostScript printers can be very verbose. In fact, PostScript jobs are actually programs sent to the printer; they need not produce paper at all and may return results directly to the computer. PostScript also uses two-way communication to tell the computer about problems, such as errors in the PostScript program or paper jams. Your users may be appreciative of such information. Furthermore, the best way to do effective accounting with a PostScript printer requires two-way communication: you ask the printer for its page count (how many pages it has printed in its lifetime), then send the user's job, then ask again for its page count. Subtract the two values and you know how much paper to charge the user.


11.3.1.1.2 Parallel Ports

To hook up a printer using a parallel interface, connect the Centronics cable between the printer and the computer. The instructions that came with the printer, the computer, or both should give you complete guidance.

Remember which parallel port you used on the computer. The first parallel port is /dev/ppc0 to FreeBSD; the second is /dev/ppc1, and so on. The printer device name uses the same scheme: /dev/lpt0 for the printer on the first parallel ports etc.


11.3.1.1.3 Serial Ports

To hook up a printer using a serial interface, connect the proper serial cable between the printer and the computer. The instructions that came with the printer, the computer, or both should give you complete guidance.

If you are unsure what the ``proper serial cable'' is, you may wish to try one of the following alternatives:

  • A modem cable connects each pin of the connector on one end of the cable straight through to its corresponding pin of the connector on the other end. This type of cable is also known as a ``DTE-to-DCE'' cable.

  • A null-modem cable connects some pins straight through, swaps others (send data to receive data, for example), and shorts some internally in each connector hood. This type of cable is also known as a ``DTE-to-DTE'' cable.

  • A serial printer cable, required for some unusual printers, is like the null-modem cable, but sends some signals to their counterparts instead of being internally shorted.

You should also set up the communications parameters for the printer, usually through front-panel controls or DIP switches on the printer. Choose the highest bps (bits per second, sometimes baud rate) rate that both your computer and the printer can support. Choose 7 or 8 data bits; none, even, or odd parity; and 1 or 2 stop bits. Also choose a flow control protocol: either none, or XON/XOFF (also known as ``in-band'' or ``software'') flow control. Remember these settings for the software configuration that follows.


11.3.1.2 Software Setup

This section describes the software setup necessary to print with the LPD spooling system in FreeBSD.

Here is an outline of the steps involved:

  1. Configure your kernel, if necessary, for the port you are using for the printer; section Kernel Configuration tells you what you need to do.

  2. Set the communications mode for the parallel port, if you are using a parallel port; section Setting the Communication Mode for the Parallel Port gives details.

  3. Test if the operating system can send data to the printer. Section Checking Printer Communications gives some suggestions on how to do this.

  4. Set up LPD for the printer by modifying the file /etc/printcap. You will find out how to do this later in this chapter.


11.3.1.2.1 Kernel Configuration

The operating system kernel is compiled to work with a specific set of devices. The serial or parallel interface for your printer is a part of that set. Therefore, it might be necessary to add support for an additional serial or parallel port if your kernel is not already configured for one.

To find out if the kernel you are currently using supports a serial interface, type:

# grep sioN /var/run/dmesg.boot

Where N is the number of the serial port, starting from zero. If you see output similar to the following:

sio2 at port 0x3e8-0x3ef irq 5 on isa
sio2: type 16550A

then the kernel supports the port.

To find out if the kernel supports a parallel interface, type:

# grep ppcN /var/run/dmesg.boot

Where N is the number of the parallel port, starting from zero. If you see output similar to the following:

ppc0: <Parallel port> at port 0x378-0x37f irq 7 on isa0
ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
ppc0: FIFO with 16/16/8 bytes threshold

then the kernel supports the port.

You might have to reconfigure your kernel in order for the operating system to recognize and use the parallel or serial port you are using for the printer.

To add support for a serial port, see the section on kernel configuration. To add support for a parallel port, see that section and the section that follows.


11.3.1.3 Adding /dev Entries for the Ports

Note: FreeBSD 5.0 includes the devfs filesystem which automatically creates device nodes as needed. If you are running a version of FreeBSD with devfs enabled then you can safely skip this section.

Even though the kernel may support communication along a serial or parallel port, you will still need a software interface through which programs running on the system can send and receive data. That is what entries in the /dev directory are for.

To add a /dev entry for a port:

  1. Become root with the su(1) command. Enter the root password when prompted.

  2. Change to the /dev directory:

    # cd /dev
    
  3. Type:

    # ./MAKEDEV port
    

    Where port is the device entry for the port you want to make. Use lpt0 for the printer on the first parallel port, lpt1 for the printer on the second port, and so on; use ttyd0 for the first serial port, ttyd1 for the second, and so on.

  4. Type:

    # ls -l port
    

    to make sure the device entry got created.


11.3.1.3.1 Setting the Communication Mode for the Parallel Port

When you are using the parallel interface, you can choose whether FreeBSD should use interrupt-driven or polled communication with the printer. The generic printer device driver (lpt(4)) on FreeBSD 4.X and 5.X uses the ppbus(4) system, which controls the port chipset with the ppc(4) driver.

  • The interrupt-driven method is the default with the GENERIC kernel. With this method, the operating system uses an IRQ line to determine when the printer is ready for data.

  • The polled method directs the operating system to repeatedly ask the printer if it is ready for more data. When it responds ready, the kernel sends more data.

The interrupt-driven method is usually somewhat faster but uses up a precious IRQ line. Some newer HP printers are claimed not to work correctly in interrupt mode, apparently due to some (not yet exactly understood) timing problem. These printers need polled mode. You should use whichever one works. Some printers will work in both modes, but are painfully slow in interrupt mode.

You can set the communications mode in two ways: by configuring the kernel or by using the lptcontrol(8) program.

To set the communications mode by configuring the kernel:

  1. Edit your kernel configuration file. Look for an ppc0 entry. If you are setting up the second parallel port, use ppc1 instead. Use ppc2 for the third port, and so on.

    • If you want interrupt-driven mode, for FreeBSD 4.X add the irq specifier:

      device ppc0 at isa? irq N
      

      Where N is the IRQ number for your computer's parallel port.

      For FreeBSD 5.X, edit the following line:

      hint.ppc.0.irq="N"
      

      in the /boot/device.hints file and replace N with the right IRQ number. The kernel configuration file must also contain the ppc(4) driver:

      device ppc
      
    • If you want polled mode, do not add the irq specifier:

      For FreeBSD 4.X, use the following line in your kernel configuration file:

      device ppc0 at isa?
      

      For FreeBSD 5.X, simply remove in your /boot/device.hints file, the following line:

      hint.ppc.0.irq="N"
      

      In some cases, this is not enough to put the port in polled mode under FreeBSD 5.X. Most of time it comes from acpi(4) driver, this latter is able to probe and attach devices, and therefore, control the access mode to the printer port. You should check your acpi(4) configuration to correct this problem.

  2. Save the file. Then configure, build, and install the kernel, then reboot. See kernel configuration for more details.

To set the communications mode with lptcontrol(8):

  1. Type:

    # lptcontrol -i -d /dev/lptN
    

    to set interrupt-driven mode for lptN.

  2. Type:

    # lptcontrol -p -d /dev/lptN
    

    to set polled-mode for lptN.

You could put these commands in your /etc/rc.local file to set the mode each time your system boots. See lptcontrol(8) for more information.


11.3.1.3.2 Checking Printer Communications

Before proceeding to configure the spooling system, you should make sure the operating system can successfully send data to your printer. It is a lot easier to debug printer communication and the spooling system separately.

To test the printer, we will send some text to it. For printers that can immediately print characters sent to them, the program lptest(1) is perfect: it generates all 96 printable ASCII characters in 96 lines.

For a PostScript (or other language-based) printer, we will need a more sophisticated test. A small PostScript program, such as the following, will suffice:

%!PS
100 100 moveto 300 300 lineto stroke
310 310 moveto /Helvetica findfont 12 scalefont setfont
(Is this thing working?) show
showpage

The above PostScript code can be placed into a file and used as shown in the examples appearing in the following sections.

Note: When this document refers to a printer language, it is assuming a language like PostScript, and not Hewlett Packard's PCL. Although PCL has great functionality, you can intermingle plain text with its escape sequences. PostScript cannot directly print plain text, and that is the kind of printer language for which we must make special accommodations.


11.3.1.3.2.1 Checking a Parallel Printer

This section tells you how to check if FreeBSD can communicate with a printer connected to a parallel port.

To test a printer on a parallel port:

  1. Become root with su(1).

  2. Send data to the printer.

    • If the printer can print plain text, then use lptest(1). Type:

      # lptest > /dev/lptN
      

      Where N is the number of the parallel port, starting from zero.

    • If the printer understands PostScript or other printer language, then send a small program to the printer. Type:

      # cat > /dev/lptN
      

      Then, line by line, type the program carefully as you cannot edit a line once you have pressed RETURN or ENTER. When you have finished entering the program, press CONTROL+D, or whatever your end of file key is.

      Alternatively, you can put the program in a file and type:

      # cat file > /dev/lptN
      

      Where file is the name of the file containing the program you want to send to the printer.

You should see something print. Do not worry if the text does not look right; we will fix such things later.


11.3.1.3.2.2 Checking a Serial Printer

This section tells you how to check if FreeBSD can communicate with a printer on a serial port.

To test a printer on a serial port:

  1. Become root with su(1).

  2. Edit the file /etc/remote. Add the following entry:

    printer:dv=/dev/port:br#bps-rate:pa=parity
    

    Where port is the device entry for the serial port (ttyd0, ttyd1, etc.), bps-rate is the bits-per-second rate at which the printer communicates, and parity is the parity required by the printer (either even, odd, none, or zero).

    Here is a sample entry for a printer connected via a serial line to the third serial port at 19200 bps with no parity:

    printer:dv=/dev/ttyd2:br#19200:pa=none
    
  3. Connect to the printer with tip(1). Type:

    # tip printer
    

    If this step does not work, edit the file /etc/remote again and try using /dev/cuaaN instead of /dev/ttydN.

  4. Send data to the printer.

    • If the printer can print plain text, then use lptest(1). Type:

      % $lptest
      
    • If the printer understands PostScript or other printer language, then send a small program to the printer. Type the program, line by line, very carefully as backspacing or other editing keys may be significant to the printer. You may also need to type a special end-of-file key for the printer so it knows it received the whole program. For PostScript printers, press CONTROL+D.

      Alternatively, you can put the program in a file and type:

      % >file
      

      Where file is the name of the file containing the program. After tip(1) sends the file, press any required end-of-file key.

You should see something print. Do not worry if the text does not look right; we will fix that later.


11.3.1.4 Enabling the Spooler: the /etc/printcap File

At this point, your printer should be hooked up, your kernel configured to communicate with it (if necessary), and you have been able to send some simple data to the printer. Now, we are ready to configure LPD to control access to your printer.

You configure LPD by editing the file /etc/printcap. The LPD spooling system reads this file each time the spooler is used, so updates to the file take immediate effect.

The format of the printcap(5) file is straightforward. Use your favorite text editor to make changes to /etc/printcap. The format is identical to other capability files like /usr/share/misc/termcap and /etc/remote. For complete information about the format, see the cgetent(3).

The simple spooler configuration consists of the following steps:

  1. Pick a name (and a few convenient aliases) for the printer, and put them in the /etc/printcap file; see the Naming the Printer section for more information on naming.

  2. Turn off header pages (which are on by default) by inserting the sh capability; see the Suppressing Header Pages section for more information.

  3. Make a spooling directory, and specify its location with the sd capability; see the Making the Spooling Directory section for more information.

  4. Set the /dev entry to use for the printer, and note it in /etc/printcap with the lp capability; see the Identifying the Printer Device for more information. Also, if the printer is on a serial port, set up the communication parameters with the ms# capability which is discussed in the Configuring Spooler Communications Parameters section.

  5. Install a plain text input filter; see the Installing the Text Filter section for details.

  6. Test the setup by printing something with the lpr(1) command. More details are available in the Trying It Out and Troubleshooting sections.

Note: Language-based printers, such as PostScript printers, cannot directly print plain text. The simple setup outlined above and described in the following sections assumes that if you are installing such a printer you will print only files that the printer can understand.

Users often expect that they can print plain text to any of the printers installed on your system. Programs that interface to LPD to do their printing usually make the same assumption. If you are installing such a printer and want to be able to print jobs in the printer language and print plain text jobs, you are strongly urged to add an additional step to the simple setup outlined above: install an automatic plain-text-to-PostScript (or other printer language) conversion program. The section entitled Accommodating Plain Text Jobs on PostScript Printers tells how to do this.


11.3.1.4.1 Naming the Printer

The first (easy) step is to pick a name for your printer It really does not matter whether you choose functional or whimsical names since you can also provide a number of aliases for the printer.

At least one of the printers specified in the /etc/printcap should have the alias lp. This is the default printer's name. If users do not have the PRINTER environment variable nor specify a printer name on the command line of any of the LPD commands, then lp will be the default printer they get to use.

Also, it is common practice to make the last alias for a printer be a full description of the printer, including make and model.

Once you have picked a name and some common aliases, put them in the /etc/printcap file. The name of the printer should start in the leftmost column. Separate each alias with a vertical bar and put a colon after the last alias.

In the following example, we start with a skeletal /etc/printcap that defines two printers (a Diablo 630 line printer and a Panasonic KX-P4455 PostScript laser printer):

#
#  /etc/printcap for host rose
#
rattan|line|diablo|lp|Diablo 630 Line Printer:

bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:

In this example, the first printer is named rattan and has as aliases line, diablo, lp, and Diablo 630 Line Printer. Since it has the alias lp, it is also the default printer. The second is named bamboo, and has as aliases ps, PS, S, panasonic, and Panasonic KX-P4455 PostScript v51.4.


11.3.1.4.2 Suppressing Header Pages

The LPD spooling system will by default print a header page for each job. The header page contains the user name who requested the job, the host from which the job came, and the name of the job, in nice large letters. Unfortunately, all this extra text gets in the way of debugging the simple printer setup, so we will suppress header pages.

To suppress header pages, add the sh capability to the entry for the printer in /etc/printcap. Here is an example /etc/printcap with sh added:

#
#  /etc/printcap for host rose - no header pages anywhere
#
rattan|line|diablo|lp|Diablo 630 Line Printer:\
        :sh:

bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\
        :sh:

Note how we used the correct format: the first line starts in the leftmost column, and subsequent lines are indented with a single TAB. Every line in an entry except the last ends in a backslash character.


11.3.1.4.3 Making the Spooling Directory

The next step in the simple spooler setup is to make a spooling directory, a directory where print jobs reside until they are printed, and where a number of other spooler support files live.

Because of the variable nature of spooling directories, it is customary to put these directories under /var/spool. It is not necessary to backup the contents of spooling directories, either. Recreating them is as simple as running mkdir(1).

It is also customary to make the directory with a name that is identical to the name of the printer, as shown below:

# mkdir /var/spool/printer-name

However, if you have a lot of printers on your network, you might want to put the spooling directories under a single directory that you reserve just for printing with LPD. We will do this for our two example printers rattan and bamboo:

# mkdir /var/spool/lpd
# mkdir /var/spool/lpd/rattan
# mkdir /var/spool/lpd/bamboo

Note: If you are concerned about the privacy of jobs that users print, you might want to protect the spooling directory so it is not publicly accessible. Spooling directories should be owned and be readable, writable, and searchable by user daemon and group daemon, and no one else. We will do this for our example printers:

# chown daemon:daemon /var/spool/lpd/rattan
# chown daemon:daemon /var/spool/lpd/bamboo
# chmod 770 /var/spool/lpd/rattan
# chmod 770 /var/spool/lpd/bamboo

Finally, you need to tell LPD about these directories using the /etc/printcap file. You specify the pathname of the spooling directory with the sd capability:

#
#  /etc/printcap for host rose - added spooling directories
#
rattan|line|diablo|lp|Diablo 630 Line Printer:\
        :sh:sd=/var/spool/lpd/rattan:

bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\
        :sh:sd=/var/spool/lpd/bamboo:

Note that the name of the printer starts in the first column but all other entries describing the printer should be indented with a tab and each line escaped with a backslash.

If you do not specify a spooling directory with sd, the spooling system will use /var/spool/lpd as a default.


11.3.1.4.4 Identifying the Printer Device

In the Adding /dev Entries for the Ports section, we identified which entry in the /dev directory FreeBSD will use to communicate with the printer. Now, we tell LPD that information. When the spooling system has a job to print, it will open the specified device on behalf of the filter program (which is responsible for passing data to the printer).

List the /dev entry pathname in the /etc/printcap file using the lp capability.

In our running example, let us assume that rattan is on the first parallel port, and bamboo is on a sixth serial port; here are the additions to /etc/printcap:

#
#  /etc/printcap for host rose - identified what devices to use
#
rattan|line|diablo|lp|Diablo 630 Line Printer:\
        :sh:sd=/var/spool/lpd/rattan:\
        :lp=/dev/lpt0:

bamboo|ps|PS|S|panasonic|Panasonic KX-P4455 PostScript v51.4:\
        :sh:sd=/var/spool/lpd/bamboo:\
        :lp=/dev/ttyd5:

If you do not specify the lp capability for a printer in your /etc/printcap file, LPD uses /dev/lp as a default. /dev/lp currently does not exist in FreeBSD.

If the printer you are installing is connected to a parallel port, skip to the section entitled, Installing the Text Filter. Otherwise, be sure to follow the instructions in the next section.


11.3.1.4.5 Configuring Spooler Communication Parameters

For printers on serial ports, LPD can set up the bps rate, parity, and other serial communication parameters on behalf of the filter program that sends data to the printer. This is advantageous since:

  • It lets you try different communication parameters by simply editing the /etc/printcap file; you do not have to recompile the filter program.

  • It enables the spooling system to use the same filter program for multiple printers which may have different serial communication settings.

The following /etc/printcap capabilities control serial communication parameters of the device listed in the lp capability:

br#bps-rate

Sets the communications speed of the device to bps-rate, where bps-rate can be 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600, 19200, 38400, 57600, or 115200 bits-per-second.

ms#stty-mode

Sets the options for the terminal device after opening the device. stty(1) explains the available options.

When LPD opens the device specified by the lp capability, it sets the characteristics of the device to those specified with the ms# capability. Of particular interest will be the parenb, parodd, cs5, cs6, cs7, cs8, cstopb, crtscts, and ixon modes, which are explained in the stty(1) manual page.

Let us add to our example printer on the sixth serial port. We will set the bps rate to 38400. For the mode, we will set no parity with -parenb, 8-bit characters with cs8, no modem control with clocal and hardware flow control with crtscts: