Multicast, macvtap, bridge

Hello list,

I'm trying to have guests communicate with each other on multicast. I don't know where to look to enable this, and if its possible. My guests communicate normally with each other on their bridged (macvtap) interface on unicast, but I cannot seem to be able to do it with multicast.

Other tests conducted between bare metal hosts are successful, so my testing methods don't seem to be the problem here. I'm using sockperf.

All the interfaces I'm using, either on host or guest, have MULTICAST enabled.

What am I missing ?

Thanks for your help.