[ntp:questions] Re: synchronization

Ron Croonenberg ronc at depauw.edu
Fri Mar 10 16:12:54 UTC 2006


Richard B. Gilbert wrote:

>> noquery
> 
> 
> noquery, on a line by itself is invalid!!!!  If it were valid, you would 
> be shooting yourself in the foot because "noquery" means "do not respond 
> to querys" which means your server couldn't serve time anyway!!!!

Well..  I took the "default" config file and it was in there..  so I 
left it there.

>> ============================================================================== 
>>
>> +time-b.nist.gov .ACTS.           1 u   43   64  377   36.473  3598.51 
>> 33.187
>> *tick.usnogps.na .USNO.           1 u   50   64  377  107.202  3594.40 
>> 31.645
>> +NAVOBS1.MIT.EDU .PSC.            1 u   43   64  377   36.762  3596.60 
>> 32.328
>> ********************************************************
> 
> 
> This is a pretty dismal looking ntpq banner!!  The offsets say that your 
> clock is off by more than three seconds.  At the maximum slew rate of 
> 500 parts per million, it will take several hours to bring your clock 
> into synchronization.

yes I know..  that's why I noticed there to be a problem

> How are you starting ntpd?  What options are you using?  If you use the 
> -g option, ntpd should set the clock unconditionally at startup; e.g. it 
> should query the servers to find out what time it is and then set your 
> clock to that time.

I start it with : 'service ntpd start"
That results into : ntpd -U ntp -p /var/run/ntpd.pid

> Next, the three servers you are using appear poorly chosen.   You should 
> not be using stratum 1 servers unless you will be serving time to 
> several hundred clients!  All the public stratum 1 servers are generally 
> loaded to the breaking point and should be avoided if possible.  The 
> figures for round trip delay are quite high!  107 milliseconds is 
> downright unreasonable!  36 is not very good either.  The highest delay 
> I have is 19 milliseonds.   Look for servers closer to you; e.g. with 
> shorter round trip delays.

Ok..  so how do I find different servers ?

> You should be using four servers.  Four is the minimum number of servers 
>  required to defend against one false ticker.  Two is the worst possible 
> number.  Three is better but if one fails. . . .

I can do that..  if I know where to find 4 decent/good servers.

> I'd suggest removing or commenting out ALL the restrict statements until 
> you get everything else working.  Then you can uncomment or replace them 
> and see if they break anything.

I can do that..  although I don't think the restrict lines are not 
breaking anything. The timeserver does "connect" but the synchronisation 
   is lost  all the time it seems.

thanks,

Ron




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