[ntp:questions] Compensating for asymmetric delay on a per-peer/server basis?

Rob nomail at example.com
Wed Sep 10 07:34:16 UTC 2014

Rich Wales <richw at richw.org> wrote:
> Replying to "Rob":
>> Yes, you can use:  fudge time1 -0.002  or similar.
>> see the manual.
> This didn't work.  And the following error message appeared in my syslog:
>     inappropriate address for the fudge command,
>     line ignored
> As best I can tell from the online manual, the "fudge" command is
> defined only for local reference clocks and has no effect on peers
> or servers.

Ok you are right.  In fact I filed bug #2598 myself for a similar
situation...   In my case I wanted to compensate for the delay asymmetry
for external users using my GPS reference via my ADSL line.  So I
would like to apply such a fudge command to a network interface, not
to a peer server.

I forgot that it is not even possible to apply it to a server, what you
would like to do.  I think the only thing you can do is apply an offset
to your GPS and live with the fact that you are always 2ms off.  At least
then you don't have a time wander when you switch to your backup and
the external users of your system get the correct time.  That is what
I did as a workaround until someone fixes this in ntpd.

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