[ntp:questions] frequency adjusting only

Danny Mayer mayer at ntp.isc.org
Tue Apr 22 12:15:55 UTC 2008


maxime louvel wrote:
> Thanks for your answer,
> 
> I can't have a step on the clock because that would screw up my
> applications.
> However if I keep the load within a certain range I should fine, don't I ?
> I am synchronising one node to several public NTP servers, and the others
> nodes are synchronised to the first one.
> There are 2 to 24 nodes in my sub net.
> Do you think that should be feasible ?
> 
> Maxime

You need at least 3 and preferably 4 public NTP servers in order for 
your local server to make decisions about which one is giving the most 
accurate and reliable time at any moment. 2 is not enough since there's 
no way to decide which is better. 3 allows 2 to gang up on the third.

2-24 nodes is nothing. Even bombarding the NTP server with queries will 
barely be noticed. Don't forget at a minimum a node won't send a query 
more frequently than once every 64 seconds unless you are using a badly 
implemented NTP client.

Danny



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