[ntp:questions] Transparent NTP in-node forwarding

Danny Mayer mayer at gis.net
Fri May 27 00:26:43 UTC 2005

At 04:44 AM 5/26/2005, Jiri Hlusi wrote:
>Does anybody have an idea how to setup NTP request forwarding
>between different IPs on the same node?
>- My server has its fixed node IP, and ntpd running properly
>- Later on, I'd like to introduce another virtual IP on the same
>   server, possibly bound to the same or even different NIC on
>   the same machine
>- As the last, I'd like to use "something" that would allow me to
>   forward NTP messages received on the Virtual IP to the NTP
>   port on the node IP, and re-route received responses back
>   back to the original requestor
>Can something like that work at all (e.g. from the NTP protocol
>The core reason for the above construct is that the Virtual IP
>used should serve as a reference point for external dependent
>entities, while I'd be still free to change my node IP anytime
>I need to do so. Secondly, I'd alos like to be able to start/stop
>the service anytime needed....
>NTPD seems to bind to all available IP interfaces at its startup,
>and there is no chance to change this later. Hence, in case that the
>Virtual IP is introduced *after* local ntpd is started (due to whatever
>reason), the only way to make ntpd to use it is to restart the daemon
>as such. That's something I wouldn't like to do .....

See bug #51 in bugzilla. This won't be fixed anytime soon. It doesn't
take much to restart ntpd so why not do it for your situation? I don't
have any understanding of what you want to do in rerouting packets
but that should be something doable outside of NTP. I believe
that NAT firewalls do that kind of thing.


>Thanks a lot!
>-- Jiri
>questions mailing list
>questions at lists.ntp.isc.org

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