[ntp:questions] Max polling time

Danny Mayer mayer at ntp.isc.org
Sat Mar 17 02:01:13 UTC 2007

Richard B. gilbert wrote:
> RICCARDO wrote:
>> I'm going to set Minpoll and Maxpoll time in my ntpd.conf for my NTP
>> internal server (MASTER) which must be synchronized to external
>> servers (stratum 1 or 2), because I think 64s is too low so i want to
>> increase it.
>> I have another 2 internal time servers (A, B) which must be
>> synchronized to my MASTER server.
>> Clients will use A and B servers.
>> Which time do you suggest me for A, B and MASTER servers ? I know that
>> these values represent degree of 2.
>> Maxpoll ?
>> Minpoll ?
>> Are These option supported in ntp 4.x in Fedora Linux ?
> It is generally a BAD IDEA to change the default values of MINPOLL and 
> MAXPOLL.  NTPD will change the polling interval to the value within 
> those limits that is best suited to the existing situation.  When ntpd 
> is first started all the servers will be polled at intervals of MINPOLL 
> seconds.  As ntpd gains confidence that it knows what time it is and 
> which are the best servers, it will increase that polling interval.  If 
> conditions (primarily network delay times) change, it will adjust the 
> polling interval for best performance.

I'd also like to point out that the increase in the polling interval is
part of the engineering of the algorithms since it also acts as a
dampener to wild swings that may occur as it tries to approach *best
chime*. If you don't understand the algorithms you shouldn't touch the
poll settings.


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