I ran into an interesting problem this past weekend. A neighbor of mine was trying to play Warcraft II Battle.Net edition over an IPX network. I had properly installed the IPX networking components on both of his computers, and he had been working just fine. He called me this Monday and said that he could no longer connect to games over IPX. He was receiving a "waiting for response" message from the connecting computer, once he attempted to connect to the game created by the source computer. The fact that he could see the game over the network told me that IPX was at least partially working.
I tried setting his IPX frametypes to 802.3, and even tried remapping his internal IPX network numbers to something other than the defaults (he is using Windows XP). Nothing worked. Some things made it worse. I even tried uninstalling and reinstalling IPX. No luck. The solution ended up being the removal of some additional protocols that had been installed (noone seems to know who did it) - The Network Monitor protocol and the IPV6 Developer Edition protocol had both been installed on one of the machines. It is POSSIBLE, I guess, that the Network Monitor protocol was grabbing the IPX packets and not giving them back (sensing that they were not meant for that client machine, perhaps?). Knowing that Warcraft II probably used some old IPX gaming code and was not optimized for machine->machine communications leads me to believe this was probably the case. Hopefully, my posting the solution will aid others who have the problem.