[ntp:questions] Monitoring NTP - nptq -p

Spoon devnull at localhost.com
Fri Mar 23 15:39:15 UTC 2007


Keith E. Brandt, M.D. wrote:

> /home/brandt 53> ntpq -p
>       remote           refid      st t when poll reach   delay   offset  jitter
> ==============================================================================
> *GPS_NMEA(0)     .GPS.            0 l    2   64  377    0.000    0.005   0.017
> -ntp.your.org    130.126.24.44    3 u   47   64  377   62.065    4.289   2.750
> +boudicca.tux.or 65.212.71.102    2 u   12   64  377   63.289   -5.525   2.273
> -dake.desynched. 132.163.4.103    2 u   18   64  377   55.516    4.039   2.726
> -veritas.imagepi 67.128.71.76     2 u   60   64  377   51.816   -8.385   2.495
> -hudson.yutanigl 128.252.19.1     2 u   20   64  377   50.768   -5.847  14.944
> +ferocious.dairi 140.142.16.34    2 u   18   64  377  119.579   -0.465  11.587
> 
> 'Poll' is the polling interval in seconds, which seems to vary quite 
> a bit on my system, so here's the first real question - how does ntp 
> pick the polling interval (a pointer to the docs is fine, I just 
> haven't been able to uncover it yet).

Have you played with minpoll and maxpoll?

http://www.eecis.udel.edu/~mills/ntp/html/confopt.html

minpoll minpoll
maxpoll maxpoll

     These options specify the minimum and maximum poll intervals for 
NTP messages, in seconds as a power of two. The maximum poll interval 
defaults to 10 (1,024 s), but can be increased by the maxpoll option to 
an upper limit of 17 (36.4 h). The minimum poll interval defaults to 6 
(64 s), but can be decreased by the minpoll option to a lower limit of 4 
(16 s). These option are valid only with the server and peer commands.

I don't know under what conditions ntpd changes the polling interval.




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