Usually multicast groups are joined on a multicast address. On Ethernet there is a mapping between multicast addresses and multicast ethernet addresses and if the ethernet card is well behaved, filters only those multicast ethernet addresses, and the IP stack filters the multicast IP address that are wanted.
For multiple ethernet cards on one machine, a multicast routing program such as pimd (PIM) or mrouted (DVMRP) is usually used, and it forwards data when a remote client joins a multicast group (address). You sound like you want to static route the multicast traffic. I have seen default multicast routes, but have not done static multicast routes. I would not suggest you do port based routing, it will turn your multicast into broadcasts. --Mark Tinguely To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-questions" in the body of the message