I don't think it matters that host and client are the same IP. Looking at the FPSNet code it seems that when the original host drops out and another machine becomes the host it does refreshes Gnet with the new game info and it takes over the hosting functions as far as the actual code goes but it does not actually initiate a new session of Direct Play with a "StartNetGame" or "Host NetGame" as this would start a "new" game. I assume DirectPlay switches the host automatically. I can't see why it shouldn't work - maybe some DirectPlay issue ?.