[ntp:questions] Large offset and lots of time resets

Chris Albertson albertson.chris at gmail.com
Wed Feb 23 21:43:28 UTC 2011


I've noticed that "reach" goes down not only in the case of a bad
network connection but also if the data seems unreasonable by whatever
criteria.    That might explain why the polls keep working.  I'm
having the same exact problem currently with a GPS receiver that is
not setup correctly.

One thing I'd do is add at least two more "server" lines in your
ntp.conf file.  Along with the "0" pool server add lines for 1 and 2
at least.  Then NTP can use it's clock selection algorithm

What kind of network connection is this?


On Wed, Feb 23, 2011 at 12:26 PM, Maarten Deen <zqrra at kf4nyy.ay> wrote:
> A while now I'm having some problems with my ntp setup.
>
> I have simple comfig file:
> $ cat /etc/ntp.conf
> # /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help
>
> driftfile /var/lib/ntp/ntp.drift
> logfile /var/log/ntp.log
>
> server 0.nl.pool.ntp.org
>
> but the offset is usually around 2000 and the jitter hovers around 700:
> $ ntpq -np
>     remote           refid      st t when poll reach   delay   offset
> jitter
> =========================================================================
> =====
> *217.67.231.25   193.67.79.202    2 u   43   64  377   23.005  2073.00
> 719.806
>
> In ntp.log I continuously see lines like this:
> 23 Feb 19:09:51 ntpd[27664]: time reset +2.393091 s
> 23 Feb 19:21:52 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 19:25:10 ntpd[27664]: time reset +2.307869 s
> 23 Feb 19:35:17 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 19:40:40 ntpd[27664]: time reset +2.338134 s
> 23 Feb 19:51:24 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 19:55:43 ntpd[27664]: time reset +2.269268 s
> 23 Feb 20:01:27 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 20:11:09 ntpd[27664]: time reset +2.328620 s
> 23 Feb 20:20:17 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 20:26:50 ntpd[27664]: time reset +2.362413 s
> 23 Feb 20:34:17 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 20:42:53 ntpd[27664]: time reset +2.421296 s
> 23 Feb 20:52:05 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 20:58:31 ntpd[27664]: time reset +2.356457 s
> 23 Feb 21:04:48 ntpd[27664]: synchronized to 217.67.231.25, stratum 2
> 23 Feb 21:14:26 ntpd[27664]: time reset +2.400477 s
>
> This goes on and on and on. And regularly ntp stops having connection,
> reach goes to 1 and builds up again. Never that it is a poll that's been
> missed, it is always back to 1 as if ntpd has started itself up again.
>
> I'm using ntp 4.2.4p4 on a Ubuntu box. Linux kernel 2.6.24.
>
> What's wrong in this setup?
>
> Regards,
> Maarten
>
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>



-- 
=====
Chris Albertson
Redondo Beach, California



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