[time] problems with your ntp service
Sun Feb 10 12:21:26 UTC 2008
Udo van den Heuvel wrote:
> I got one of them emails even though the machine is running OK;
> I did not change anything about ntp, the box has been up for 71 days and
> yet the graph at pool.ntp.org shows an offset going downhill.
> Also the network config has not been changed. There is slight traffic
> shaping, as has been there for ages on my side of the connection, just
> to prevent issues like these.
> What is the most likely cause?
In my experience (at least for my own system) the offset graph is
showing the network latency towards the monitoring server, rather than
the quality of my clock.
I see no irregularities over the past days, but in the past the offset
sometimes was quite high.
I keep a couple of external reference clocks in addition to my two local
clocks (GPS and DCF), so I can monitor my own ntp's view on the offset
and compare it to what the monitoring server thinks.
When your own "ntpq -p" does not show an offset and there is one at
www.pool.ntp.org, it must be somewhere in the network.
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