[ntp:questions] How should an NTP server fail?

David L. Mills mills at udel.edu
Wed Jun 9 23:56:18 UTC 2010


The tally code is updated when the selection algorithm runs at each 
received update. The peer reach register is updated when a poll is sent. 
If caught at just the right moment, it might happen that when a poll is 
sent the reach register becomes zero and before the next update is 
received, in which case your behavior is possible. Even in that rare 
case there resulting behavior would not be incorrect, as the clock is 
not updated untl the next update is received and the tally code 


Miroslav Lichvar wrote:

>On Wed, Jun 09, 2010 at 09:34:06PM +0100, David L. Mills wrote:
>>If a source is considered invalid,
>>unreachable or the maximum error statistic exceed the select
>>threshold, the tally indicator surely will be blank. If a source is
>>marked as the system peer, it surely is valid and reachable.
>The tally indicator sometimes stays at * even when the peer is
>unreachable, that's why I have filed the bug 1554. There are steps to
>reproduce and a description of the events in clock filter which are
>causing the problem.

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