[ntp:questions] Force ntpd to immediately trust server

Harlan Stenn stenn at ntp.org
Tue Feb 19 06:36:12 UTC 2008

>>> In article <64B9BEB4F544624B9D59DB6F61E2E65402AD784E at AZ25EXM03.gddsi.com>, John.Johnson at gdc4s.com (Johnson, John-P63914) writes:

John-P> Thank you for the responses.
Harlan> How many seconds?  In many cases, we can do this in 11 seconds (and
Harlan> there is talk now about residual slew time).

John-P> 11 seconds would be great.  How do we do it?

Use iburst in your config files and have a "good" driftfile.

See http://support.ntp.org/Support - the Configuring and Starting sections
in particular.

Harlan> the other is "what frequency are we operating at?"

John-P> Are you referring to the drift file?  I know that the lack of a
John-P> drift file slows down start up because ntpd takes time to determine
John-P> the frequency offset.  My servers have drift files. Is there more to
John-P> it?

If you have a good drift file, then this is what I mean.

I was considering the point that when ntpd starts up and gets the time, it
my be correct *then*, but until ntpd has had enough time to make sure the
clock frequency is correct, ntpd cannot accurately say what time it is
*later*, at least until it has calculated the operating frequency.

This is a simplification, but I think you get the point.

Harlan Stenn <stenn at ntp.org>
http://ntpforum.isc.org  - be a member!

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