wM <-> wM communication through firewall

We have 2 wM integration servers speaking to each other across a firewall. Both are setup to communicate on the default HTTP port 5555. This port is open on the firewall, but it seems the wM servers cannot communicate. Does wM require other ports to be open on the firewall? Are there other protocols being employed here, apart from HTTP?

Thanks in advance for your advice.

Subhankar Sarkar

At the network level please check where are the Network packets are getting missed. The 5555 will work fine and seems it is mainly a network setup issue. Have you set up the proxy properly?