From owner-freebsd-doc Mon Oct 1 6:50:23 2001 Delivered-To: freebsd-doc@freebsd.org Received: from bazooka.trit.org (bazooka.trit.org [63.198.170.138]) by hub.freebsd.org (Postfix) with ESMTP id 59E5E37B410; Mon, 1 Oct 2001 06:43:48 -0700 (PDT) Received: by bazooka.trit.org (Postfix, from userid 1000) id EF4D93E01; Mon, 1 Oct 2001 06:43:47 -0700 (PDT) Received: from bazooka (localhost [127.0.0.1]) by bazooka.trit.org (Postfix) with ESMTP id E3A2C3C130; Mon, 1 Oct 2001 06:43:47 -0700 (PDT) To: Tom Hukins Cc: setantae , "Bruce A. Mah" , Wouter Van Hemel , doc@freebsd.org Subject: Re: Please review: NTP section for Handbook In-Reply-To: <20011001140336.A29053@eborcom.com>; from tom@FreeBSD.org on "Mon, 1 Oct 2001 14:03:36 +0100" Date: Mon, 01 Oct 2001 06:43:42 -0700 From: Dima Dorfman Message-Id: <20011001134347.EF4D93E01@bazooka.trit.org> Sender: owner-freebsd-doc@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Tom Hukins wrote: > Thanks for the comments - the feedback I received has been really > helpful. > > I've updated the document at > http://people.FreeBSD.org/~tom/tmp/ntp.sgml to incorporate all the > suggestions I received. Attached is a patch that fixes some more minor problems. Most of the changes are mechanical, such as &man.ntp.8; -> &man.ntpd.8; and other such typos. The only non-mechanical change is about the driftfile. Your explanation was a ways off; it does not countain "information about previous responses from the NTP servers you are using". In fact, I think ntpd can compute the drift without an external time source. Thanks for the great work! --- ntp.sgml~ Mon Oct 1 13:10:51 2001 +++ ntp.sgml Mon Oct 1 13:38:10 2001 @@ -1,3 +1,4 @@ + @@ -29,7 +30,7 @@ ntpd FreeBSD ships with the &man.ntpd.8; NTP server which can be used to query other NTP servers to set the clock on your - machine. + machine, and/or provide time service to others. @@ -64,15 +65,17 @@ machine boots up, you can use &man.ntpdate.8;. This may be appropriate for some desktop machines which are frequently rebooted and only require infrequent synchronization, but - most machines should run &man.ntp.8;. + most machines should run &man.ntpd.8;. + + Using &man.ntpdate.8; at boot time is also a good idea for machines that run &man.ntp.8;. &man.ntp.8; changes the clock gradually, whereas &man.ntpdate.8; sets the clock, no matter how great the difference between a machine's current clock setting and the correct time. To enable &man.ntpdate.8; at boot time, add ntpdate_enable="YES" to /etc/rc.conf. You will also need to specify all servers you wish to synchronize with and any - flags to be passed to &man.nptdate.8; in + flags to be passed to &man.ntpdate.8; in ntpdate_flags. @@ -82,7 +85,8 @@ NTP is configured by the /etc/ntp.conf file in the format - described in &man.ntp.conf.5; as follows: + described in &man.ntp.conf.5;. The simplest form looks + like this: server ntp.isp.example.com prefer server timeserver.foobardomain.org @@ -90,6 +94,12 @@ driftfile /var/db/ntp.drift + + The server option specifies which servers are to be used, with one server listed on each line. If a server is specified with the prefer @@ -99,11 +109,12 @@ server because it is on the same network as your machine or more reliable. - The driftfile option specifies which - file is used to store information about previous responses - from the NTP servers you are using. This file contains - internal information for NTP. It should not be modified by - any other process. + The driftfile option specifies which file + is used to store the system clock's frequency offset. + &man.ntpd.8; uses this to automatically compensate for the + clock's natural drift, allowing it to maintain a reasonably + correct setting even if it is cut off from all external time + sources for a period of time. @@ -130,7 +141,7 @@ /etc/ntp.conf can contain multiple restrict options. For more details, see - the Access Control Support of + the Access Control Support subsection of &man.ntp.conf.5;. @@ -181,7 +192,6 @@ preventing NTP from from functioning since replies never reach your machine. - @@ -190,6 +200,5 @@ Documentation for the NTP server can be found in /usr/share/doc/ntp/ in HTML format. - To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message