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Date:      Mon, 05 Apr 1999 20:58:29 -0500
From:      David Kelly <dkelly@hiwaay.net>
To:        "Paul D. Schmidt" <pds@enteract.com>
Cc:        pds@uberhacker.org, freebsd-questions@FreeBSD.ORG
Subject:   Re: time synchronization 
Message-ID:  <199904060158.UAA05872@nospam.hiwaay.net>
In-Reply-To: Message from "Paul D. Schmidt" <pds@enteract.com>  of "Mon, 05 Apr 1999 20:09:00 CDT." <Pine.BSF.4.05.9904052007440.17195-100000@uberhacker.org> 

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"Paul D. Schmidt" writes:
> Are there any programs for periodic time syncs?  AFAIK, ntpdate or
> whatever only runs once at boot....and since you don't have to reboot
> FreeBSD machines often....:)

You can run ntpdate as often as you like. Run it from cron if you wish.

Otherwise there is timed(8) which is a quick and easy way for your local
machines to keep themselves synced to each other. SGI Irix systems ship
with xntpd from the factory. Believe SGI donated the timed code to BSD. 

If you wish to sync Irix machines its easiest to use xntpd on the
FreeBSD system to get a good reference off the net, and use "timeslave"
on the Irix systems to sync off the FreeBSD system. For timeslave to
work the FreeBSD system needs either the daytime or time service (I
forget) enabled in /etc/inetd.conf. Am guessing is the TCP version of 
"time". You can test it quickly from Irix with the "timedc" command. 
Once in timedc, "c FreeBSD" where FreeBSD is the name of your FreeBSD 
system, should quickly respond with the difference in clock times. If 
it takes 30 seconds to get an answer then the wrong thing is enabled in 
inetd.conf.

Timed won't go thru a router.

xntpd(8) is the "continuous" version of ntpdate(8). You might have
noticed the man pages for xntpd and ntpdate refer to each other under
SEE ALSO. Xntpd works to calibrate your clock to minimize
synchronization traffic. See http://www.eecis.udel.edu/~ntp/ for more
details.

In /usr/ports/net/ntp you could find ntp-4.0.91, which is the latest and
greatest definitive network time stuff. Recently FreeBSD 3.1 and
-current saw a commit of kernel changes to optimally implement the
advanced concepts being promoted my the ntp architects.

As for my needs, xntpd is Good Enough(tm). Xntpd runs funky on many of 
the SGI systems I've tried it on, but quite solid on FreeBSD. So I 
timeslave my SGI systems off my FreeBSD system.


--
David Kelly N4HHE, dkelly@nospam.hiwaay.net
=====================================================================
The human mind ordinarily operates at only ten percent of its
capacity -- the rest is overhead for the operating system.




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