I already posted on the Xbox forums, so I will copy and paste:
the nat on my xbone is always goin from open to strict without notice, but it's usually always strict.
I have tried everything, I even spent 375$ on different routersI. I think it may be my Modem, it is 16 yrs old.
on the Xbox I made a static ip, and on every router I bought I did all the port forwarding, and took Down the firewall.
i had a Cisco e1000, it worked ok, not great, with my 360, still had some issues. So I bought a Cisco e3000, a newer model. It kept going stric as well as it kept dropping signal to all the computers in the house. So I bought a d-linkac1300 dgl 5500, which I'm using now and I still have the same issue, but instead of the computers dropping signal, my gf's xbox is. And the nat still won't stay open.
I still own all 3 pod these routers, if someone could help . I was giving thought to buying a new modem, if you think that a would work.
and yes I connected my Xbox straight to the Modem and the NAT is open. but their are 5 people in my house so I can't hog the Internet.
I have a Motorola modem. Any advice or help at all?