[ntp:questions] Ntp not syncing after powerfail of server

M. Giertzsch mgiertzsch at mobotix.com
Thu May 19 16:14:24 UTC 2011

Am 19.05.2011 17:52, schrieb M. Giertzsch:
> Am 19.05.2011 16:01, schrieb Heiko Gerstung:
>> Hi,
>> Am 18.05.2011 11:57, schrieb M. Giertzsch:
>>> Hello together,
>>> I want to synchronise a local network and there is no uplink to the
>>> outside world.
>>> So I have one dedicated ntp server and all other devices are client
>>> of this server.
>>> Now if there is a powerfail, there is no guarantee that the server
>>> has finished the boot
>>> before the clients have. In this case the time will not be synced.
>>> Is anybody aware of options taking account to this? Does anyone know
>>> threads
>>> or howtos for further reading? Am I doing a mistake or do I have my
>>> clients missconfigured?
>> Maybe I am missing something, but if you use ntpd on the client
>> machines, they will poll the server in intervals. So even if
>> they do not get a response the first time they ask, they should
>> receive the time on the second try (and all consecutive calls).
>> We have no chance to tell you whether you have misconfigured your
>> clients, because we do not know
>> - what OS your clients are running on
>> - what kind of NTP software you are using (ntpd version X or
>> something else?) on the clients and on the server
>> - how your current configuration looks like (ntp.conf?)
>> I could imagine that your clients probably use ntpdate or a similar
>> software to query the time once during startup, but that
>> is just me guessing your setup. If that would be the case, all you
>> could probably do is inserting a sleep before the ntpdate
>> call or some other ugly workaround like this.
>> Regards,
>>   Heiko
>> _______________________________________________
>> questions mailing list
>> questions at lists.ntp.org
>> http://lists.ntp.org/listinfo/questions
> Hello Heiko,
> thanks for your help. You are totally right, I have forgotton to give
> you all these informations required.
> The NTP software in use is ntpd 4.2.0a on both client and server.
> Well, I can't tell you exactly the OS in use,
> but it's a linux like OS running on an embedded arm device.
> The NTP configuration looks like follows:
> restrict default notrap nomodify nopeer noquery
> restrict
> driftfile /var/status/ntp.drift
> pidfile /var/run/ntpd.pid
> server 0.de.pool.ntp.org iburst
> server 1.de.pool.ntp.org iburst
> server 2.de.pool.ntp.org iburst
> server
> fudge stratum 13
ups, this is wrong of course....
this config was taken from a wrong client.

restrict default notrap nomodify nopeer noquery
driftfile /var/status/ntp.drift
pidfile /var/run/ntpd.pid
server iburst
fudge stratum 13

And regarding the linux: It's kernel

> May it be that iburst is the problem? Client gives up because of too
> many non-responses, or will iburst
> ignore these and send another bunch a little later?
> If you need any more information please ask me.
> Thank you in anticipation.

Best regards,
    M. Giertzsch

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