[ntp:questions] Why is NTPD adjusting the system clock when in LOCAL(0) mode?

Charles Elliott elliott.ch at verizon.net
Wed Jun 15 15:21:26 UTC 2011



                I wrote a clock simulator program that, among other things,
outputs the current time adjustment every second.  The only active lines in
NTPD's conf file are:


# your local system clock, could be used as a backup

# (this is only useful if you need to distribute time no matter how good or
bad it is)

server iburst minpoll 4 maxpoll 4

# but it should operate at a high stratum level to let the clients know and
force them to

# use any other timesource they may have.

fudge stratum 12


Yet NTPD is constantly changing the curTimeAdjustment.  Here is the evidence
from my program:

CTA: 156003

CTA: 156004

CTA: 156003



I know that NTPD is doing this because when I stop it, my simulator outputs

CTA: 156001

CTA: 156001

CTA: 156001


until I restart NTPD, at which time it goes back to speeding up the system


On what basis could NTPD possibly adjust the system time when it is using
the local clock as its only time source?  What standard is NTPD comparing
the time to?


I am running Windows 7 64-bit and the version of NTPD I am using is ntpd
4.2.4p7 at copenhagen-o May 22 11:25:36 (UTC+02:00) 2009  (3).


Thanks in advance for your help.




Charles Elliott

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