multicasting + default gateway

Hello,

Recently installed an application that used the Rendezvous bus on
RedHat 3.x intel .
Some of the boxes worked just fine others not - saying something
about multicastung not being available.
It seemed that those that were happy had a default geteway set - and
those that were broken did not. Add a default gateway to all of the
boxen asd all was fine.
Is this a bug in say the intereaction between the NIC and TCP-IP?
Or is it expected behaviour by multicasting? I have done some googling
on multicasting and I think it is a bug - Am I right?

TIA

Ton

On Dec 7, 1:34 am, ton de w <ton_de_win...@yahoo.co.uk> wrote:
> Hello,
>
> Recently installed an application that used the Rendezvous bus on
> RedHat 3.x intel .
> Some of the boxes worked just fine others not - saying something
> about multicastung not being available.
> It seemed that those that were happy had a default geteway set - and
> those that were broken did not. Add a default gateway to all of the
> boxen asd all was fine.
> Is this a bug in say the intereaction between the NIC and TCP-IP?
> Or is it expected behaviour by multicasting? I have done some googling
> on multicasting and I think it is a bug - Am I right?
>
> TIA
>
> Ton

No, I believe this is by design. Multicasting is not limited to your
subnet - in fact intermediary routers will build spanning trees on the
fly for that multicast address, and maintain the routing entries for
that group. So it makes sense that multicasting is not available if
the box cannot contact a gateway to send this information..

ton de w wrote:
> Hello,
>
> Recently installed an application that used the Rendezvous bus on
> RedHat 3.x intel .
> Some of the boxes worked just fine others not - saying something
> about multicastung not being available.
> It seemed that those that were happy had a default geteway set - and
> those that were broken did not. Add a default gateway to all of the
> boxen asd all was fine.
> Is this a bug in say the intereaction between the NIC and TCP-IP?
> Or is it expected behaviour by multicasting? I have done some googling
> on multicasting and I think it is a bug - Am I right?
>
> TIA
>
> Ton

Maybe something like

ip ro add dev eth0 224.0.0.0/4

would have fixed it.

Andy.