Linux – Selecting interface for multicast traffic

Have you tried moving the network card that needs to multicast up in priority?

• Open Control Panel\Network and Internet\Network Connections
• Press your ALT key, then choose the Advanced menu and select Advanced Settings.
• Under Adapters and Bindings, move the multicast NIC above the Internet Access NIC in the Connections field.

Let me know if that works.

I've used tcpdunp a fair bit but don't find it very easy so I use ngrep which supports regex too.

ngrep -t -d eth3 '' broadcast and ngrep -t -d eth3 '' multicast should both put the interface into promiscuous mode and achieve the same thing.

I'm not suggesting that this is much different from what you're trying with tcpdump but in case for some reason it's misbehaving then ngrep is another tool on top of the Java tool to try.