[ntp:questions] ntpd: time reset problem
kostecke at ntp.org
Fri Sep 11 16:10:36 UTC 2009
On 2009-09-11, Frank Elsner <Elsner at tubIT.TU-Berlin.DE> wrote:
> strange happening yesterday. See this logfile lines:
Is this a VM?
> Sep 10 20:45:52 seymour ntpd: synchronized to 184.108.40.206, stratum 1
> Sep 10 20:58:07 seymour ntpd: synchronized to 220.127.116.11, stratum 1
> Sep 10 21:21:02 seymour dovecot: dovecot: Fatal: Time just moved backwards by 434 seconds. [ ... ]
That's 7.25 minutes. Note that the last message from ntpd was ~23
minutes prior to the message from dovecot.
> Sep 10 21:26:36 seymour ntpd: no servers reachable
> Sep 10 21:42:56 seymour ntpd: synchronized to 18.104.22.168, stratum 1
> Sep 10 21:50:55 seymour ntpd: time reset +434.824810 s
This is where ntpd realized the the time was off.
> Sep 10 21:54:09 seymour ntpd: synchronized to 22.214.171.124, stratum 2
> Sep 10 21:55:07 seymour ntpd: synchronized to 126.96.36.199, stratum 1
> What happened to the clock between 20:58:07 and 21:42:56?
I'd be more concerned about what happened between the ntpd log entry at
Sep 10 20:58:07 and the dovecot error message at Sep 10 21:21:02. That's
the period where something pushed the clock back by ~7.25 minutes.
> I guess ntpd should never set the time the hard way.
It only did so because the clock was pushed so far off in such a short
> The software is ntp-4.2.4p2-1.fc6. Yes, I know it's old.
It's a little old. But not ancient.
Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/
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