I have a network formed by some Cisco switches (a 2960 at the center, some 2950s for distribution). The network uses VLANs, and there are trunks between the various switches. Computers in the same VLAN can happily talk across multiple switches. Inter-VLAN routing is handled by a firewall (Microsoft TMG 2010), but this is not relevant, because the traffic I'm concerned with is confined to a single VLAN.
There is an application which uses IGMP to broadcast messages between multiple computers (as I said above, in the same VLAN), and it doesn't work.
What should I do on those switches to allow the application to work?
I had the same problem with an AiroNet access point, and I was able to solve it using the command
no ip igmp snooping; however, this command seems to not have the same effect on the switches.