[ntp:questions] ntpd: time reset problem

Brian Utterback brian.utterback at sun.com
Mon Sep 14 11:48:51 UTC 2009


Hmm. It's interesting that the value is almost exactly 1/10th the 
value in the thread. But it doesn't seem to be that a single rogue 
return from gettimeofday could have caused this. The system clock does 
end up 434 seconds behind, relative to the server, so it doesn't seem 
like a transient error could cause this.

It would be interesting to know what OS the OP is running.

Todd Glassey wrote:
> Brian Utterback wrote:
>> Richard B. Gilbert wrote:
>>
>>   
> You may find this interesting.  http://lkml.org/lkml/2007/8/23/96
>>>> 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. [ ... ]
>>>> 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
>>>>       
>>
>>  
>>> Your clock got yanked around by at least one rogue server!  This sort 
>>> of thing is the reason for configuring four, five, or seven servers.
>>>
>>> It might be helpful if you post your ntp.conf file.
>>>     
>>
>> No, it wasn't yanked by a rogue server. It wasn't yanked by NTP at 
>> all. If NTP set the clock backwards, there would be a message that 
>> says so. Instead, dovecot notices, and then sometime later NTP notices 
>> and puts it back to where it is supposed to be. This isn't an NTP 
>> issue at all, it was something external to NTP that yanked the clock.
>>
>> Brian Utterback
>>
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> 

-- 
blu

It's bad civic hygiene to build technologies that could someday be
used to facilitate a police state. - Bruce Schneier
----------------------------------------------------------------------
Brian Utterback - Solaris RPE, Sun Microsystems, Inc.
Ph:877-259-7345, Em:brian.utterback-at-ess-you-enn-dot-kom



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