[ntp:questions] Synchronize clocks without a reference clock

Spoon devnull at localhost.com
Wed Mar 21 16:24:51 UTC 2007


Richard B. gilbert wrote:

> Spoon wrote:
> 
>> Consider a cluster of computers on a LAN. These computers have no
>> acess to a reference clock (no Internet, no GPS, etc).
>>
>> One could still want to have all their clocks synchronized, even if
>> this means they are all slowly drifting away from the "real" time.
>>
>> I've read a FAQ which seems to describe this use case.
>> http://www.ntp.org/ntpfaq/NTP-s-refclk.htm#AEN4264
>>
>> All I need to do would be to add these lines:
>>
>> server 127.127.1.1        # LCL, local clock
>> fudge  127.127.1.1 stratum 12    # increase stratum
>>
>> to my configuration file? Did I understand correctly?
> 
> That will cause ntpd to serve the local clock.   You can, instead, use 
> something called orphan mode in which several machines agree on a 
> common, but not necessarily correct, time.  I've never done it.  See the 
> documentation for details.

As far as I understand, orphan mode works through broadcast, correct?

If I have a pair of computers A and B in different subnets, and they can 
only talk to each other, then my only option is to configure A to serve 
its local clock, and B as a client of A. Is that correct?

Regards.




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