I didn't make it!
Ahh so this is perhaps the cause of my woes. My net connection is via a combined ADSL Modem / Gateway / Router that shares it between 3 - 5 machines depending on how many are on. While im able to connect to a number of online games on the net, Ive gotten rather fed up with having a list of 20 or more games, and only having HALF of them with ping ( ive pretty much come to the conclusion that if a game in the join game screen doesnt have a ping, then you cant get in, so dont bother. ) and a number with ping being unreachable. My "router" for lack of a better word is under featured so while i Would have tried forwarding every port i need, that would require me to disable ALL other port forwards. :( It has tempted me on a number of occasions to setup an entire machine ( i got a few 200Mhz boxes just laying round and my nets under 10Mbit so any network cards i got will work and i got tons lol ) as a dedicated router box so i can solve these issues by somehow disabling all routing on the gateway/modem and directly connecting it to one machine, etc and so on. Now, ive noticed im rambling so back to the issue, Likely causes, Port forwarding, you probably forwarded a few ports for online play and you can get to the online lobby etc.? but from the looks of it, the only way to ensure you have no issues with online play is A: Direct Connect modem without any hardware firewalling stuff or routing or anything that messes things round, or B: Forward all the ports, theres a list of the required ports in the Master TroubleShooting list thread. if anyone else has some clue what the Gamespy NAT negotiation is supposed to do feel free to explain! Since its not doing crap for me as far as i can tell. Or is the NAT negotiation why i can "see" games i cant connect to... its negotitating em past their NATs to gamespy but cant manage the same feat between me and them... idunno anyway. Hope the port forwarding info helps you.