ntp settings

[Marton Ferenc]

Hello
I get stratum 3 via other ntp servers from internet source and stratum 1 from ntp server based on gps. I want to set that stratum3 be the primaty and stratum 1 be the secondary source on this machine. how do I do that?

Thanks
m.f.

xntpd

[Peter Godron]

Hi,
have you looked at modifying the /etc/ntp.conf file

Please also read:
http://forums1.itrc.hp.com/service/forums/helptips.do?#33 on how to reward any useful answers given to your questions.

[rick jones]

There may be a way to say one server is preferred, but I suspect that is not an absolute and that a stratum 1 timesource could still be chosen (I'm just guessing though).

Any particular reason you want to take the decision of the server to which it should sync from the hands of the ntpd?

[Bill Hassell]

When you have multiple NTP servers, it is best not to use a preferred source. NTP is a complex series of tests and calculations to mitigate the issues of distance and latency. Most GPS sources are not nearly as accurate as Internet sources but because of the calculations used over long periods of time, you will get excellent (less than 1 second, typically less than 128 ms) accuracy.

Let xntpd keep the time accurate and put AT LEAST 3 NTP sources in you config file. The best choice is to use the NTP pool servers and you GPS source as the 4th source. Get info on the pool from:

http://www.pool.ntp.org/

This is all you need in ntp.conf:

server 0.us.pool.ntp.org # US pool 0
server 1.us.pool.ntp.org # US pool 1
server 2.us.pool.ntp.org # US pool 2
fudge 127.127.1.1 stratum 10 # localhost fallback
driftfile /etc/ntp.drift # monitor drift

Change the NTP pool to match your closest pool server set.