We have a Firewall and my basic Chat app does not work here.
This is interesting because I'm also behind a fairly tight firewall and have no trouble getting through to the servers using the example chat program. I'm no expert, but I think RTMP can tunnel, and if that is the case it should slip through firewalls that might be inspecting the packets to see if they are indeed valid HTTP packets. I'm not sure though if they RTMP tunneling is turned on by default or if its the regular non-tunneling RTMP they are using for this.
So, here is the deal: currently Cocomo only supports rtmps (rtmp over SSL) and not rtmpt (rtmp tunneling over http), but we do have support for going through a proxy. Only problem: I think I found a bug because I don't see the messages that say that we are trying to connect through the proxy.
I'll try a fix in the next few days (and if you can open a bug it would help us to not forget 🙂 but it would be very helpful if you could tell us how your firewall / proxy is configured so that we can do some testing (the current code was inherited from an older project and the people that wrote it, tested it and had some clue on how to setup a proxy for testing are long gone 🙂