Having a multicast problem - cant figure it out.

Hey Guys!

So out of the gate, I'm super weak on Mulitcast. Never really had to mess with it. Let me explain whats going on.

We have two devices that need to keep a constant link to each other. Device 1 reads incoming data, and Device 2 Reads outgoing data. They constantly keep an active link between each other to pass an identifier. When Device 1 has incoming data, it tags that specific data with an identifier, so when it hits Device 2, it knows whats leaving.

Before, the devices were connected directly to each other, and everything worked fine. Now, we want to be able to run reports out of these devices, which requires them to either be internet facing, or, we can manually log into them and run the report ourselves.

When we moved the devices over to our internal LAN, the devices fail to stay connected to eachother. They will connect for about 8 seconds, then drop off. I done a port mirror on each of their ports, and found that I'm getting hundreds of ICMP Failures coming from all of our local devices on the LAN. I'm assuming this is essentially a DOS attack - all the devices on the LAN are replying all at once, and it's overloading the two Devices.

To test this, I moved them over to their own VLAN, and, they connected fine. I would normally just leave them on their own VLAN, but I have about 15 different (vendor) switches in between (Recently took over this network.) so I would like to avoid having to put it on it's on VLAN.

So - is there a way I can configure the switch they're plugged into to only pass multicast traffic on two ports? Anything else I could do to try to fix this?

I do have IGMP enabled on the switch the devices are plugged into, but not the other switches.

The switch they're plugged into is a HP 2530G - it's a fully managed layer 2 switch.

Thanks for the help!!!