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Re: ntpd; local clock reference

[ quotes are not in chronological order ]

* Brenda J. Butler <bjb@achilles.net> [2002-12-31 18:43:19 -0500]:
> Another question:  If I do get this to work, will the ntpd
> on seal continue to correct the time even when the outside
> link is down and the "local clock" is being used as
> reference?

Yes, if you put something like the following:

    server  # local clock
    fudge stratum 10  

into your ntp.conf file, it will treat the local clock as a reference
clock -- albeit with an artificially "bad" stratum level.

When your link is up, the time servers that seal connects to will have
much higher stratum numbers (usually >=4), so the local clock will be
effectively ignored, but when the link is down, your local clock will be
used as a reference clock -- since it will be the only time server

After ntp has been running properly for a while, it will figure out your
clock's drift (i.e. how bad it is at keeping time), and so if your net
connection does go down, it can keep fairly accurate time on its own
using the drift value.

[ I didn't see your original email so I am going to reply to it here. ] 

> > I have a dial-up system that is going to be a server for my home
> > network.  I want my inside machines to sync to seal (the ss20) and
> > seal to sync to outside machines when the link is up, and to just
> > provide time to the inside machines when the link is down.

Yes, this is how most people should have their network set up. Configure
ntp on seal to something like this:

    server ntp.time0.com
    server ntp.time1.com
    server ntp.time2.com

and all the other machines should be configured like this:

    server seal.yourdomain.net

See the ntp pages for more detailed info.


N. Thomas
Etiamsi occiderit me, in ipso sperabo

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