[ntp:questions] NTP driving me nuts!

Danny Mayer mayer at ntp.isc.org
Sun Dec 31 21:35:54 UTC 2006


JCA wrote:
>> >     192.168.0.1 is the IP address of C in my LAN. In the ntpq traces
>> > above B's ntp.conf file was using
>> >
>> >     server reloj.kjsl.com
>>
>> Does DNS resolve this to the same address?
> 
>   Yes.
> 
>> >
>> > rather than
>> >
>> >    server 192.168.0.1
>> >
>> >     C's ntp.conf configuration file:
>> >
>> > server  127.127.1.0     # local clock
>> > fudge   127.127.1.0 stratum 10
>> >
>> > server reloj.kjsl.com

If this is pointing to itself why is this here?

>> > server ntp1.sf-bay.org
>> >
>> > driftfile /var/run/ntp.drift
>> >
>>
> 
>> >    If in A's and B's configuration files I use the line
>> >
>> >    server reloj.kjsl.com
>> >
>> > instead of
>> >
>> >   server 192.168.0.1
>> >
>> > then A and B keep the time all right. C keeps the time all right with
>> > the configuration file above.
>> >
>>
>> Is reloj.kjsl.com on that address or a different address?
> 
>    reloj.kjsl.com is an external server - nothing to to with my LAN.
> 192.168.0.1 is the IP address of C in my LAN - nothing to do with
> reloj.kjsl.com.
> 

This contradicts what you just said above. So which is it?\

>> If it's the
>> same address as C then you need to remove that line from C's
>> configuration.
>>
>> >
>> >    I could of course change A's and B's ntp.conf files accordingly and
>> > see what happens. However, were this to lead to A and B synchronizing
>> > with C all right, it still would not explain why A and B had been
>> > synchronizing with C with no problems until recently.
>>
>> You network may have changed or a firewall may have been added or DNS
>> has changed.
> 
>   I don't know what my ISP does with the network, but I know that my
> setup is the same as before.
> 

Are A, B and C all on your ISP's network or are they local to your LAN?

>   The problem seems to be in C. C keeps in sync with the external
> server all right. If either A or B take their synchronization from C,
> they stay in sync for some time - hours, maybe a day. After that, they
> don't seem to get any synchronization ticks from C anymore, and their
> clocks start to drift big time.
> 
>   If, on the other hand, either A or B get their synchronization from
> the same external host as C does, then they keep in sync indefinitely
> all right. C keeps in sync with the external clock all right.
> 

C is not synching so A and B cannot synchronize with it.

>   I am totally puzzled by this behavior. Might it be that a dying
> clock battery in one or more of my PCs could be the cause. I mean, is
> it not the case that when a battery is losing power the clock becomes
> more and more erratic, so much so that ntpd might altogether refuse to
> adjust it? Can this possibility be explored with the NTP software?
> 

No, you need to figure out what's wrong with C.

Danny



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