[ntp:questions] NIST server anomaly

Mike Cook michael.cook at sfr.fr
Sun Aug 2 09:20:58 UTC 2015


While modifying a couple of servers ntp configs to test their UT1 service I noticed the following that seem odd. If anyone has seen the same I would like to know and if there are plausible explanations I would also be interested.

The issue pertains to server time-c.nist.gov (129.6.15.30) which <http://tf.nist.gov/tf-cgi/servers.cgi> show has all services available.

I have just executed ntpdate -d  129.6.15.30 on two different systems. The results are as follows, with uninteresting lines removed.

mike at bb1:~$ ntpdate -d 129.6.15.30
 2 Aug 08:51:00 ntpdate[26533]: ntpdate 4.2.8p3 at 1.3265-o Tue Jun 30 16:13:49 UTC 2015 (1)
Looking for host 129.6.15.30 and service ntp
129.6.15.30 reversed to time-c.nist.gov
host found : time-c.nist.gov
transmit(129.6.15.30)
….
receive(129.6.15.30)
server 129.6.15.30, port 123
stratum 2, precision -22, leap 00, trust 000
refid [129.6.15.30], delay 0.11169, dispersion 0.00015
transmitted 4, in filter 4
reference time:    d9685702.8297381a  Sun, Aug  2 2015  8:44:50.510
…..
offset 0.000847

ntpq -pn on this system showed
 129.6.15.30     43.77.130.254    2 u   13   16  377   86.501    1.132   0.582


mike at cubieez2:~/src/python$ sudo ntpdate -d 129.6.15.30
 2 Aug 10:50:59 ntpdate[21672]: ntpdate 4.2.8p3-RC1 at 1.3265-o Sun Jun  7 13:29:09 UTC 2015 (1)
Looking for host 129.6.15.30 and service ntp
129.6.15.30 reversed to time-c.nist.gov
host found : time-c.nist.gov
transmit(129.6.15.30)
…..
receive(129.6.15.30)
server 129.6.15.30, port 123
stratum 1, precision -29, leap 00, trust 000
refid [ACTS], delay 0.17868, dispersion 0.00026
transmitted 4, in filter 4
reference time:    d968583c.1e7f0dab  Sun, Aug  2 2015 10:50:04.119
….
offset -0.008539

(forget the 2hr diff in reported  times as the shell for the first command is running with a UTC TZ and the second has a TZ of CEST)

ntpq -pn on this system shows
 129.6.15.30     .ACTS.           1 u   15   64  377  151.910   -8.515   0.081


What intrigues me is that the refid is not the same. Any idea why?  Isn’t having inconsistent data from the same configurations an issue?

Regards
Mike



"Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une petite et provisoire sécurité, ne méritent ni liberté ni sécurité."
Benjimin Franklin


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