XS, would you take a look at Drunkjugs router settings and go throught the motions to see if you can help him attain stable OPEN NAT on his xboxes? See if you can help him narrow down any configuration issues.
I am starting to wonder if there are some modem issues here. The only thing that I could think if is maybe the ISP. He and are currently running the same modem and 4500 HW. The only thing different is the ISP service. Possible there could be something going on with modem, modem FW or ISP service.
Drunkjug, the only thing i can suggest would be to either test both a different modem and router to see whats going on. I would say test the router at a different location however that would entail taking all xboxes too. Thats not a good thing. So I would go to your local store, some place that has a good refund policy and get a different router, try a DIR series router, something you can test for 30 days before you have to decide to keep or return it.
I would offer you to send me your 4500 during this time frame to see if our 4500 issues follow at a different location. I would like to help you eliminate and narrow down that root cause. I don't think the 4500 is at fault. One way to test this is at a different location.
Your seeing some odd things going on there. Name Bench for me always seem to bring up the same 3 or 4 addresses doing a couple of tests. Didn't vary at all. Your seeing different addresses per each test? I might think something is going on there with that. If the ISP service and modem and lines are good, addresses should change, if they do, no much if at all.
Lets see what XS can do with a review.