[ntp:questions] problem with synchronizing two comps to each other

Maarten Wiltink maarten at kittensandcats.net
Thu May 19 15:04:05 UTC 2005

"Mike" <miodek.STOP.SPAM at thebestnudes.com> wrote in message
news:d6i7kg$3tr$1 at korweta.task.gda.pl...

> so you're telling, that it will be easier to update time from external
> server? beacause I thought, that if 1 comp (master) keeps the time,
> the other one (client) will adjust to it over LAN network. That it
> will give beter results in setting the same time on both comps.

No, it will avoid one specific failure mode. The one where one server is
running fast, and one is running slow, both with respect to real time,
and neither speed difference is out of spec (500 PPM) for NTP, but the
difference between them is. For instance, if one host is 350 PPM fast
and the other is 350 PPM slow, they could both synchronise to UTC, but
not to the other when it is free-running, because that is a 700 PPM
difference and NTP simply quits at 500.

Also, a free-running clock may not run at the same speed all the time.
Reference clocks do, by design. Since speed and time difference are
not caught up with immediately, that will result in higher offsets.

Maarten Wiltink

More information about the questions mailing list