[ntp:questions] ntpd: time reset problem

Steve Kostecke 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[9104]: synchronized to 192.53.103.108, stratum 1
> Sep 10 20:58:07 seymour ntpd[9104]: synchronized to 134.34.3.18, 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[9104]: no servers reachable
> Sep 10 21:42:56 seymour ntpd[9104]: synchronized to 192.53.103.104, stratum 1
> Sep 10 21:50:55 seymour ntpd[9104]: time reset +434.824810 s

This is where ntpd realized the the time was off.

> Sep 10 21:54:09 seymour ntpd[9104]: synchronized to 130.149.7.71, stratum 2
> Sep 10 21:55:07 seymour ntpd[9104]: synchronized to 129.69.1.153, 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
time.

> 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/




More information about the questions mailing list