Selecting interface for multicast traffic?

Question

How do I specify an interface for multicast traffic? I need to connect to multicast group through vlan interface (tcpdump show traffic there) but I believe that IGMP request are sent throug eth0.

Should I add a route for multicast adresses?

Answer 1

route add -net 224.0.0.0 netmask 240.0.0.0 dev vlan100

Answer 2

Here is a static config for Ubuntu
put in your /etc/network/interfaces files

auto vlan500
iface vlan500 inet static
address 192.168.X.X
netmask 255.255.X.X
vlan-raw-device ethX