[ntp:questions] Re: New to NTPD

Richard B. Gilbert rgilbert88 at comcast.net
Wed May 10 01:17:51 UTC 2006


Ted Gervais wrote:

> On Tue, 9 May 2006, Richard B. Gilbert wrote:
> 
> 
> -snip-
> 
>>>      remote           refid      st t when poll reach   delay   
>>> offset jitter
>>> ============================================================================== 
>>> +clock.via.net   .GPS.            1 u  223  256  377  101.718   
>>> 21.183 5.465
>>>  gnomon.cc.colum .USNO.           1 u  483 1024  301   55.229   
>>> 26.100 2.439
>>> -NAVOBS1.MIT.EDU .PSC.            1 u   11  256  377   60.820   
>>> 28.740 2.602
>>> +ntp3.usv.ro     .PPS.            1 u   15  256  377  173.654   
>>> 26.977 1.469
>>> *clock.xmission. .GPS.            1 u  216  256  377   88.717   
>>> 23.674 4.681
>>> +c-24-130-58-99. .GPS.            1 u   83  256  377  118.072   
>>> 23.165 1.358
> 
> 
>> <big snip>
>>
>> You seem to have very large round trip delays to the servers you have 
>> chosen. Shorter delays are better.  The error in transmitting time 
<snip>
> 
> Alright.  I made some changes to the servers (as you mentioned).. how 
> does this look now?  It has only been running 30 mins at this time:
> ---------
>      remote           refid      st t when poll reach   delay   offset 
> jitter
> ============================================================================== 
> 
>  mircx.com       129.6.15.29      2 u   23  128    7   70.362   27.808 
> 7.917
>  neate.neateroll 199.212.17.15    3 u   24  128    7   80.833   14.010 
> 6.666
>  d221-85-115.com 132.246.168.9    2 u   17  128    7   41.316   25.977 
> 2.463
> ----------------
> 
<snip>

Your reach field shows that only the three most recent polls were 
successful!!!!  This is not good.  Did you disconnect the network cable 
or have a network problem?  That is probably why none of the three 
servers has been selected.

Can you find a fourth server?  Four are the minimum required to protect 
against one falseticker.  Five protect against two falsetickers and 
seven against three.   With only three servers, the failure of one 
leaves you with only two.  It is written that a man with two clocks can 
never be certain what time it is!!

You need to let that system run for a while, perhaps for as long as a 
full day to reach a stable state with good synchronization.




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