Ethereal-users: [Ethereal-users] Monitoring multicast traffic on router

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From: "Adam McLaurin" <ethereal@xxxxxxxxxx>
Date: Wed, 20 Apr 2005 14:52:07 -0400
Hi,

I'm running ethereal 0.10.7 (with GTK+-2 GUI) on a RH9 router, which
runs mrouted for multicast routing.

My mrouted is set up to be completely stupid and forward any incoming
multicast packet to all interfaces (except for the interface that
received the packet). I have verified mrouted is working by following
the debug log, viewing the state dump, and viewing the cache dump.

The router is used to connect two subnets; in other words, the next hop
from the router is always the actual destination node.

Using ethereal on eth0 and eth1, I can see the multicast packets coming
in. However, even when the destination nodes (on different subnets)
clearly receive the multicast packet, I do *not* see the packet being
sent out from the router.

What I expect to see on the router is something along these lines:
1) node A joins multicast group 0 via eth0
2) node B joins multicast group 0 via eth1
3) node A sends multicast packet to group 0
4) router sends multicast packet to group 0 on eth1
5) node B receives multicast packet on group 0
6) node B sends multicast packet to group 0
7) router sends multicast packet to group 0 on eth0
8) node A receives multicast packet on group 0

Anyway, is there some special that I need to do in ethereal to see the
forwarded multicast traffic from the router (steps 4 and 7)?

Thanks,
Adam McLaurin