I have a set up in which 2 HP servers are connected to netscreen firewall via an L2 switches. So as per the design, heartbeat probes are to be initiated from the Server1 goes to the layer 2 switch1 and from there needs to go to the layer 2 switch2 and from there communicates with Server2.
These HB probes are to exchange over the Multicast range. So, for this do i need to enable the multicasting on the firewall (L3 interface) or on the L2 interface i can pass the traffic if the servers are in same vlans.
The multicast traffic should be able to pass if the servers are in the same vlan. If they are not in the same vlan, then it would have to pass through the firewall. In order to pass this traffic through the firewall, you would need a regular policy permitting it. Multicast policies are only used for multicast control messages (join/prune, etc). Another thing to watch for is IGMP snooping on the switches. You may have to turn that off.