[ntp:questions] Keeping NTP Honest

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Fri Jul 10 20:19:27 UTC 2009


Unruh wrote:
> Evandro Menezes <evandro at mailinator.com> writes:
>> As I mentioned before, in some cases, NTP relies too
>>  much on low-stratum servers, even when they're blatantly
>>  wrong.  For instance, the last leap second event, when
>>  many pool servers were poorly configured.
>
>> Mulling over that, I wondered how I could tip NTP to
>>  scale down the poll period in such cases.  So I tried
>>  this trick and it seems to work fairly well when only
>>  one server is kaput:
>
>> server   pool.ntp.org iburst maxpoll 6
>> server 0.pool.ntp.org
>> server 1.pool.ntp.org
>> server 2.pool.ntp.org
>> server 3.pool.ntp.org
>
>> By having one server that remains polled every 64s, NTP
>>  could realize more quickly that there was something
>>  rotten in Denmark.  However, if that one server is
>>  neither selected nor a candidate, this trick doesn't
>>  work.  I'd hesitate to make it the preferred server
>>  though.
>
>> Thoughts?
>
> And you have at least a 1/5 chance that IT is the bad server.
>  What do you do then?

Ignore the strat 1s with floor?  e.g.

tos minclock 5 minsane 4 floor 2
pool us.pool.ntp.org preempt iburst
pool pool.ntp.org preempt iburst

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