[ntp:questions] Disappointing results from ntpd

Richard B. Gilbert rgilbert88 at comcast.net
Sun Aug 10 16:47:02 UTC 2008


Daniel Norton wrote:
> Any idea why I'm frequently seeing my system drift off by over 750
> ms ? This system has been running ntpd for weeks without configuration
> changes.  Below is from a few minutes after stuffing ntpdate down its
> throat (after stopping and restarting ntpd):
> 
> # ntpdate -q
> server 140.99.51.115, stratum 3, offset 0.274883, delay 0.08795
> server 72.233.76.194, stratum 3, offset 0.276196, delay 0.04480
> server 207.210.74.166, stratum 2, offset 0.276172, delay 0.06688
> server 66.250.45.2, stratum 2, offset 0.276772, delay 0.09192
> server 64.202.112.65, stratum 2, offset 0.281568, delay 0.07211
> 10 Aug 09:47:41 ntpdate[16596]: adjust time server 207.210.74.166
> offset 0.276172 sec
> # ntpd --version
> ntpd - NTP daemon program - Ver. 4.2.4p4
> # lsb_release -d
> Description:    Ubuntu 8.04
> # uname -a
> Linux linux1 2.6.24-16-server #1 SMP Thu Apr 10 13:58:00 UTC 2008 i686
> GNU/Linux
> # cat /var/lib/ntp/ntp.drift
> -7.300
> # cat /etc/ntp.conf
> driftfile /var/lib/ntp/ntp.drift
> 
> server 0.us.pool.ntp.org prefer minpoll 11 maxpoll 13
> server 1.us.pool.ntp.org minpoll 12 maxpoll 14
> server 2.us.pool.ntp.org minpoll 12 maxpoll 16
> server 3.us.pool.ntp.org minpoll 12 maxpoll 17
> 
> restrict -4 default kod notrap nomodify nopeer noquery
> restrict -6 default kod notrap nomodify nopeer noquery
> restrict 127.0.0.1
> restrict ::1

Lose the MINPOLL and MAXPOLL in your server statemetns!!!!  The default 
values of 6 and 10, respectively, are optimal for all but the weirdest 
cases!

Suggest using the "-g" option when starting ntpd.  This will cause ntpd 
to set the correct time when it starts.  Then wait until your system and 
ntpd have been running for at LEAST thirty minutes.

Then issue "ntpq -p" and post the output!




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