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Date:      Sat, 25 Jun 2005 22:11:52 -0400
From:      "fbsd_user" <fbsd_user@a1poweruser.com>
To:        "Andy Sutcliffe" <andy.sutcliffe@gmail.com>, <freebsd-questions@freebsd.org>
Subject:   RE: IPNAT / IPF / rdr issue
Message-ID:  <MIEPLLIBMLEEABPDBIEGGEKDHHAA.fbsd_user@a1poweruser.com>
In-Reply-To: <9d124e1c0506251800635f8cf7@mail.gmail.com>

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Your using the public ip address of your gateway box from the
private LAN.
In this mode NAT and thus your rdr rule is never evoked. Your
request never exits your private network. The gateway system knows
himself by that public ip address.
What you should be doing is using the www.domainname.com so the
request has to go to your ISP DNS server to get your public ip
address, then it will enter on the external interface and be
nated/rdr to correct location.
There is nothing wrong with your ipfilter configuration, your just
using the wrong URL.

-----Original Message-----
From: owner-freebsd-questions@freebsd.org
[mailto:owner-freebsd-questions@freebsd.org]On Behalf Of Andy
Sutcliffe
Sent: Saturday, June 25, 2005 9:01 PM
To: freebsd-questions@freebsd.org
Subject: IPNAT / IPF / rdr issue


I am having problems accessing internal resources (such as a web
server) from other internal clients when going from internal
client ->
public address -> internal resource.  For example, when I attempt to
reach 'mydomain.com' from client machine X, the connection is
refused
(I am of course, able to reach the web server through the internal
IP), however, I am able to access the web server via that URL from
an
external network.  I have 'mydomain.com' pointed towards the
external
IP of my gateway which in turn relays it to the internal web server.
I have included the pertinent contents of /etc/ipnat.rules as well
as
my /etc/ipf.conf file.  I am at a loss at this point...can anyone
point me in the right direction ?

Thanks in advance,
  - andy ( andy dot sutcliffe at gmail dot com)

Gateway:
  OS:FreeBSD 5.4
  Firewall: IPFilter
  Port Forwarding: IPNAT
  External eth: dc0
  Internal eth: ed0 (10.0.0.0)

Web Server
  OS: FreeBSD 5.4
 WWW: Apache 2.0

Client Machine(s)
  OS: Windows XP, FreeBSD, Linux

I have the following in /etc/ipnat.rules:

# innernet
map dc0 10.0.0.0/16 -> 0.0.0.0/32 portmap tcp/udp 40000:65000
map dc0 10.0.0.0/16 -> 0.0.0.0/32

# www
rdr dc0 0.0.0.0/0 port 80 -> 10.0.0.3 port 80

I have the following in /etc/ipf.conf:
#################################################################
# No restrictions on Inside LAN Interface for private network
# Not needed unless you have LAN
#################################################################

pass out quick on ed0 all
pass in quick on ed0 all

#################################################################
# No restrictions on Loopback Interface
#################################################################
pass in quick on lo0 all
pass out quick on lo0 all

#################################################################
# Interface facing Public Internet (Outbound Section)
# Interrogate session start requests originating from behind the
# firewall on the private network
# or from this gateway server destine for the public Internet.
#################################################################

# Allow out access to my ISP's Domain name server.
# xxx must be the IP address of your ISP's DNS.
# Dup these lines if your ISP has more than one DNS server
# Get the IP addresses from /etc/resolv.conf file
pass out quick on dc0 proto tcp from any to 67.43.192.6 port = 53
flags S keep state
pass out quick on dc0 proto udp from any to 67.43.192.6 port = 53
keep state
pass out quick on dc0 proto tcp from any to 137.118.1.33 port = 53
flags S keep state
pass out quick on dc0 proto udp from any to 137.118.1.33 port = 53
keep state

# Allow out access to my ISP's DHCP server for cable or DSL
networks.
# This rule is not needed for 'user ppp' type connection to the
# public Internet, so you can delete this whole group.
# Use the following rule and check log for IP address.
# Then put IP address in commented out rule & delete first rule
pass out quick on dc0 proto udp from any to 67.43.192.6 port = 67
keep state


# Allow out non-secure standard www function
pass out quick on dc0 proto tcp from any to any port = 80 flags S
keep state
pass out quick on dc0 proto tcp from any to any port = 81 flags S
keep state

# Allow out secure www function https over TLS SSL
pass out quick on dc0 proto tcp from any to any port = 443 flags S
keep state

# Allow out send & get email function
pass out quick on dc0 proto tcp from any to any port = 110 flags S
keep state
pass out quick on dc0 proto tcp from any to any port = 25 flags S
keep state

# Allow out Time
pass out quick on dc0 proto tcp from any to any port = 37 flags S
keep state

# Allow out nntp news
pass out quick on dc0 proto tcp from any to any port = 119 flags S
keep state

# Allow out gateway & LAN users non-secure FTP ( both passive &
active modes)
# This function uses the IPNAT built in FTP proxy function coded in
# the nat rules file to make this single rule function correctly.
# If you want to use the pkg_add command to install application
packages
# on your gateway system you need this rule.
pass out quick on dc0 proto tcp from any to any port = 21 flags S
keep state

# Allow out secure FTP, Telnet, and SCP
# This function is using SSH (secure shell)
pass out quick on dc0 proto tcp from any to any port = 22 flags S
keep state

# Allow out non-secure Telnet
pass out quick on dc0 proto tcp from any to any port = 23 flags S
keep state

# Allow out FBSD CVSUP function
pass out quick on dc0 proto tcp from any to any port = 5999 flags S
keep state

# Allow out ping to public Internet
pass out quick on dc0 proto icmp from any to any icmp-type 8 keep
state

# Allow out whois for LAN PC to public Internet
pass out quick on dc0 proto tcp from any to any port = 43 flags S
keep state

# Block and log only the first occurrence of everything
# else that's trying to get out.
# This rule enforces the block all by default logic.
block out log first quick on dc0 all

#################################################################
# Interface facing Public Internet (Inbound Section)
# Interrogate packets originating from the public Internet
# destine for this gateway server or the private network.
#################################################################

# Block all inbound traffic from non-routable or reserved address
spaces
block in quick on dc0 from 192.168.0.0/16 to any    #RFC 1918
private IP
block in quick on dc0 from 172.16.0.0/12 to any     #RFC 1918
private IP
# block in quick on dc0 from 10.0.0.0/8 to any        #RFC 1918
private IP
block in quick on dc0 from 127.0.0.0/8 to any       #loopback
block in quick on dc0 from 0.0.0.0/8 to any         #loopback
block in quick on dc0 from 169.254.0.0/16 to any    #DHCP
auto-config
block in quick on dc0 from 192.0.2.0/24 to any      #reserved for
docs
block in quick on dc0 from 204.152.64.0/23 to any   #Sun cluster
interconnect
block in quick on dc0 from 224.0.0.0/3 to any       #Class D & E
multicast

##### Block a bunch of different nasty things. ############
# That I do not want to see in the log

# Block frags
block in quick on dc0 all with frags

# Block short tcp packets
block in quick on dc0 proto tcp all with short

# block source routed packets
block in quick on dc0 all with opt lsrr
block in quick on dc0 all with opt ssrr

# Block nmap OS fingerprint attempts
# Log first occurrence of these so I can get their IP address
block in log first quick on dc0 proto tcp from any to any flags FUP

# Block anything with special options
block in quick on dc0 all with ipopts

# Block public pings
block in quick on dc0 proto icmp all icmp-type 8

# Block ident
block in quick on dc0 proto tcp from any to any port = 113

# Block all Netbios service. 137=name, 138=datagram, 139=session
# Netbios is MS/Windows sharing services.
# Block MS/Windows hosts2 name server requests 81
block in log first quick on dc0 proto tcp/udp from any to any port =
137
block in log first quick on dc0 proto tcp/udp from any to any port =
138
block in log first quick on dc0 proto tcp/udp from any to any port =
139
block in log first quick on dc0 proto tcp/udp from any to any port =
81

# Allow traffic in from ISP's DHCP server. This rule must contain
# the IP address of your ISP's DHCP server as it's the only
# authorized source to send this packet type. Only necessary for
# cable or DSL configurations. This rule is not needed for
# 'user ppp' type connection to the public Internet.
# This is the same IP address you captured and
# used in the outbound section.
pass in quick on dc0 proto udp from 67.43.192.6 to any port = 68
keep state

# Allow in standard www function because I have apache server
pass in quick on dc0 proto tcp from any to any port = 80 flags S
keep state
pass in quick on dc0 proto tcp from any to any port = 81 flags S
keep state

# Allow in secure FTP, Telnet, and SCP from public Internet
# This function is using SSH (secure shell)
pass in quick on dc0 proto tcp from any to any port = 22 flags S
keep state

# Allow in non-scure FTP access to file server (bombadil)
pass in quick on dc0 proto ftp from any to 10.0.0.2 port = 21 flags
S keep state
pass in quick on dc0 proto ftp from any to 10.0.0.2 port = 20 flags
S keep state
pass out quick on dc0 proto ftp from 10.0.0.2 to any port = 20 flags
S
keep state

# Block and log only first occurrence of all remaining traffic
# coming into the firewall. The logging of only the first
# occurrence stops a .denial of service. attack targeted
# at filling up your log file space.
# This rule enforces the block all by default logic.
block in log first quick on dc0 all
################### End of rules file
#####################################
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