Thompson TG585 v7 - XBOX LIVE

[#1]

Hi,
I've wrestled with this router for about 2 months......I play call of duty on xbox live and im having various problems that i cannot suss out.
I have applied the XBOXLIVE port forwarding to my xbox via the game sharing menu......The nat is still strict.
so...
I eventually worked out how to do the DMZ thing......it worked and the NAT was open - I was able to play games of call of duty and for a day or two....then all of a sudden it stopped being able to connect to other people.....I checked the NAT - and it was still open...(i dont understand this)
So i deleted XBOX from the DMZ and reapplyed it......suddenly i could play games again.......for a day or two.......(basically just loop the last part of the story a good few times)
so it seems i can get it setup but after a few days it remains "open" but i cannot connect until i remove xbox from DMZ and then put it back in again....
I'm really struggling to understand where im going wrong......
anyone any ideas?

[#2]

Dont put it in the dmz zone (How did you do that as I couldnt work it out) I had the same problem turn on UPNP and then on the xbox tell it to work it out its self ie dont ive it an ip and choose to find network settings. I have two xbox and they both work fine now but I struggled for a long time port forwarding etc

[#3]

http://192.168.1.254/cgi/b/publicip/cfg/?be=0&l0=3&l1=0&tid=ASSIGN_PUBL_ADDR
This is how i accessed DMZ - It is the only way i get the NAT to open - I cannot get the NAT to open by enabling UPNP and making the xbox connect how it wants......the NAT is strict when i do this......I wonder why its different for me?

[#4]

if your settings is like my speedtouch 716wl you should find the xbox game your playing already in the router
192.168.1.254  tool box area under games scroll down the list pick it out
I cannot show you the pictures because i changed to a draytek router 2 to 3 weeks ago
puddy

[#5]

I tried your link and it came back not found 404 my router is Thomson Gateway
Information
Product Name: TG585 v7
Software Release: 8.2.23.0
Strange as 2 xbox worked perfect on the settings for me. Does you router reset its self mine when the net went down twice reset its slef the password, sssid, ip everything just reset