[ntp:questions] NTP sync problem. "no server reachable"

Martin Burnicki martin.burnicki at meinberg.de
Fri Mar 6 09:19:09 UTC 2009


Kiran,

kiran shirol wrote:
> Hi NTP experts,
> 
> I am facing a issue in getting the NTP to sync with the server configured.
> 
> Description:
> I have a box which has 2 interfaces. One interface for the connectivity
> with the local-lan. The other
> interface is connected directly to a linux box.
> 
> IP address details :
> NTP server in the network -- 171.69.21.23
> NTP server directly connected -- 10.1.1.1
> 
> When I configure 10.1.1.1 as my NTP server, within a few seconds I am able
> to see the sync.
> When I configure the additional server 171.69.21.23, it goes out of sync.
> But I am able to see
> the packet exchange happening.
> 
> Now if i remove 10.1.1.1 from the list, I get 171.69.21.23 into sync &
> vice-versa.
> 
> When I have configured both the servers, I see "no server reachable"
> message in the debugs.
> 
> Can someone please tell me what is going on here ?
> 
> My system is a regular Linux machine. I am running a older NTP version
> 4.2.0a.

Can you send us the output of "ntpq -p" after both servers have been
configured and the NTP daemon has been running for a couple of minutes?

Possibly both upstream servers distribute times which are too different, so
your NTP daemon does not know which one has the "right" time.

This is why you should configure 3 or even more servers, see:
http://support.ntp.org/bin/view/Support/SelectingOffsiteNTPServers#Section_5.3.3.


Martin
-- 
Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont
Germany




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