Why can't I join another's game in Diablo 2?

I have a wireless home network, and several computers connected to it. I can ping any of the computers without losing any data and I can play any other game locally over our wireless network. But in Diablo 2, when I try to host a game in TCP/IP, none of the other computers can join, it says "Unable to connect to host." Anyone have any ideas as to what I can do to make this work?