Time problem with ntpd

[David G. Miller]

"jdow" <jdow at earthlink.net> wrote:

>From: "Rob Brown-Bayliss" <uncertain.genius at gmail.com>
>
>> On 10/7/06, Rob Brown-Bayliss <uncertain.genius at gmail.com> wrote:
>>    
>>
>>>>> Hi, I noticed this aftetrnoon that my system clock is about 23 minutes
>>>>> fast.  I ma using ntpd, and earlier today it was reporting the correct
>>>>> time.
>>>      
>>>
>>> 
>>> In the last few mins the time has corrected it's self.  But can UI
>>> trust the system clock any more?
>>    
>>
>You can answer that for yourself by using ntpq.
>
>>From the ntpq prompt "peers" is interesting. It allows other perhaps
>less interesting commands like "assoc" and exploration of the parameters.
>
>The command "ntpq -p" simply returns the peers list.
>
>Monitor this for extended periods and see why your system wanders off.
>It requires a day or two of continuous online time for ntpd to fully
>characterize your system and get the clock in line so that long periods
>off line (a day or so) involve no traumatic corrections or errors.
>
>{^_^}
>
You can also try the ntptrace command.  You should see something like:

# ntptrace
localhost.localdomain: stratum 4, offset 0.000022, synch distance 0.234200
mutilate.local.davenjudy.org: stratum 3, offset -0.010917, synch 
distance 0.203775
vine.desynched.net: stratum 2, offset 0.000191, synch distance 0.096220
time-C.timefreq.bldrdoc.gov: stratum 1, offset 0.000000, synch distance 
0.002650, refid 'ACTS'

If all you see is something about "127.127.1.0 stratum 10", your ntpd is 
unable to find a time source so you're running from the system clock.  
Also, ntp only syncs the system clock at shutdown.  If you leave your 
system up but drop your network connection, ntp will do its best using 
the system clock but don't expect much.  Finally, ntp will only slowly 
correct the reported time to prevent discontinuities.  It should not 
have changed the time by 23 minutes over only a few hours.  You may have 
something else going on.

Here's a link that may help: http://www.ntp.org/ntpfaq/NTP-s-trouble.htm

Cheers,
Dave

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