[ntp:questions] handling falseticker

Martin Burnicki martin.burnicki at meinberg.de
Thu Feb 19 16:09:28 UTC 2009

Hello Catia,

Since you have sent your original email to the NTP questions mailing
list you should also send copies of your replies to that list which is
an email gateway to the comp.protocols.time.ntp news group.

This would let people who are following the discussion also see what's
going on.

catia.lavalle at bechtle.com wrote:
> Hello,
> you are right this is a way to influence NTP from the command line
> without changinh the ntp.conf file, but still I do not reach my aim, at
> least not the way I imagine it.
> With ntpdc I can add a new peer (server) or remove it but not force to
> "change its mind" about two already existing peers (servers). You are
> right in he sense: if I want to exclude a server from the server list
> without stopping and restarting the deamon this is the way, but this is
> more drastic than what I would like to have.
> I mean say at time X one of the 2 stratum 1 "goes mad" such that:
>   remote        refid
> =======================
> *         .GPS.
> x10.1.1.2         .DCF.
>      .LOCL.
> the is not deleted is just "put on hold"/"right now ignored but
> not forever". If after a while it starts to give the correct time again
> it will be accepted again automatically. If I would by brute force
> remove it from the list (no matter if with a ntp restart or from command
> line) it will be away till when I manually ddecide that now it is again
> trustful and I manually re-add it to the server list.
> What I have in mind is a sort of "one time prefer command".

AFAIK there is no way to tell ntpd to behave as you want it to.

I argee with Steve Kostecke that the best way to handle this would be to
configure at least a 3rd NTP server and then leave everything up to the
NTP client.

The NTP daemon has explicitely been designed to handle such cases
automatically and gracefully, if you make the required preconditions

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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