Net Keeps Resetting to Strict Nat Type

[#1]

I have an issue with strict NAT type, I have followed the advice I have found on the forums.
It most commonly comes to...
"have you followed the advice here, http://community.plus.net/forum/index.php/topic,99917.0.html"
Which I have done, no error messages. But every time I load the game I still get the same strict NAT issues.
It almost seems to be reverting back to default each time.

[#2]

if its for your console use dmz.on router find your device and tick always use same ip then put ip in dmz and use auto settings on your xbox/ps