[ntp:questions] unexpected multicast client operation

none none at none1.invalid
Fri Feb 23 01:57:29 UTC 2007

On Wed, 21 Feb 2007 14:18:42 -0800, Steve Kostecke wrote:

> On 2007-02-21, none <none at none1.invalid> wrote:
>> I am using the NTPD (v4.1 I think) that comes out of the box with RHEL 3
>> and I have multicast set up. What I am seeing confuses me though.
>> Every time the server sends the multicast packet the client on the RHEL3
>> machine does a client/server NTP transaction back to the server.
> What you are seeing is normal. A multicast-client will use temporary
> unicast association with the multicast-server to determine the delay.
> You can supress this (w/ novolley) but then you will need to determine
> the delay manually.
>> Isn't the whole purpose of multicast so the clients just all listen
>> and not talk to the server ?
> No. Multicast association _can_ be used in architectures which only allow
> one-way communication.
>> I dont have the server listed in the clients config so it is finding the
>> server via the multicast message.
> If you _did_ have that server explicitly listed in a "client" ntp.conf
> that client would bring up a unicast assocciation with the server and
> would never bring up the multicast association.

 Thankyou for the clarifications !

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