[ntp:questions] Re: NTP sync problems

Robert Rati Robert.Rati at motorola.com
Tue Dec 14 21:02:27 UTC 2004

Richard B. Gilbert wrote:
> Robert Rati wrote:
>> I'm running NTP 4.2 on a Linux system which syncs off of 2 other Linux 
>> boxes (One Debian, other Redhat) running ntp (one is ntp 4.1, other is 
>> ntp 4.1.2) and I'm having no problems syncing.
>> However, when I use the same client in a different environment which 
>> syncs off of a Sun box running NTP 4.2 or a SUSE Linux box running NTP 
>> 4.1, I can't sync.  When I run ntpq, I see this:
>> [root@ root]# ntpq -pn
>>      remote           refid      st t when poll reach   delay   offset 
>>  jitter
>> ============================================================================== 
>> *     LOCAL(0)        10 l   31   64  377    0.000    0.000 
>>  0.001
>> x<IP>        .LCL.            1 u   35   64  377    0.272  -33.321   
>> 2.439
>> x<IP>        LOCAL(0)        11 u   44   64  377    0.416  735934.   
>> 6.326
>> The "x" status means that it is a "designated falseticker by the 
>> intersection algorithm".  What does this mean?  Is this a client or 
>> server configuration issue?  Can anyone give me some tips on how to 
>> debug this situation?
>> Rob
> You have configured two servers which have wildly different notions of 
> what time it is. Both servers are serving their unsynchronized local 
> clocks.
> Two servers is the worst possible configuration!  Ntpd knows for certain 
> that at least one of these two is "insane" and has every reason to 
> suspect that both are.

Unfortunately, the network topology I must reside within requires two 
NTP servers (and only two).  In the data I sent, while both servers have 
wildly different ideas of time, shouldn't NTP sync against the server 
with the lower stratum?  If NTP is syncing against two servers with the 
same stratum and different times, I can see that NTP wouldn't know what 
to do.  However, wouldn't NTP sync against the lower stratum server 
since there is only one server at that stratum?  Or does the time server 
sanity checking that NTP uses ignore stratum?


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