For the last 2 months, I've been having a blast playing Halo 2 with my buddies online. (except Jeff, who for some reason refuses to get on despite having all the necessary ingredients) It has worked reasonably well, with the exception of some weird incompatibilities with certain people.  If they were the party leaders, I'd get the famous "We are experiencing network issues." message.  Bungie says that this is almost always caused by NAT incompatibilities.  This didn't get in the way too much because we could usually juggle around the party leader until everyone could join.

At first, I attributed this to my out-of-the-norm network configuration.  I have VoIP, so I have several routers.  When I first started playing, I had the VoIP box as the outer-most router, followed by the venerable WRT54G.  So I was doing a double NAT.  The last several weeks, I've been trying to reduce my incompatibilities.  First, I managed to set up the VoIP router inside the firewall (I have AT&T CallVantage).  This involved....absolutely nothing.  It simply worked.  I did set up QoS on the Linksys to ensure the phone would always have enough bandwidth.  This fixed some of my incompatibilities, but other issues began to crop up, like being unable to hear everyone in the game lobby sometimes.

I had been running the wifibox firmware on the Linksys, and decided to upgrade it to a more recent, official firmware. So I upgraded to the Live-certified firmware version.  This didn't help.  Then, after changing nothing, I began having problems joining people that I had never had trouble with before.  Last night, after putting the XBox in the DMZ and still having problems, I got fed up and systematically hunted down the issue.  It was definitely something with the router, which didn't make sense since it was XBox Live certified, and I was having trouble with other people who had the same router and they didn't have problems.  It just didn't add up.

So, I broke down and got a new router, and it fixed everything.  I played until 2:00 this morning without a single problem.  VoIP still works. Wireless works.  All the PCs work.  All without any additional port forwarding, DMZ settings, or other configuration besides the QoS.  It just works now.  And do you want to know the most bizarre part?  I got the exact same model of router.

My conclusion is that the wifi-box firmware screwed it up somehow.  It's the only variable left in the equation.  I'm curious if anyone else who is running 3rd party firmware has had problems like that. Perhaps I'll link to someone that I know does, and see if that generates any discussion from his previous post.