NAT type open

Please don’t move this to the COD forums because I can never get a serious answer there.

Ok, so i am having problems connecting to my friend on codmw2. we have been playing together for a month with no problems, though. based on an internet search, it’s because my NAt isn’t all the way open. on the onlie menu of codmw2, it shows your NAT type. mine usually says OPEN. now, it says MODERATE. this is y i think we can’t connect to each other. 

i followed one guide that would assign my ps3 a static ip address and disable the DHCP setting. it worked for my ps3, but it wouldn’t let anything else (home pc, labtop) connect to the internet. so, we had to reset the router with the small button in the back. 

then i found another guide that said to put ur ps3 into a DMZ. i did that, and everything seemed to b fine(everything could connect to the internet). after an hour though, it was like our router “crashed”. nothing could connect to the internet. we reset both our modem and router 3 times but nothing would work. we then connected our modem directly to our computer to see if the problem was our internet or router. it worked fine meaning the router was the problem.

so, we left it off for about 24 hours and turned it bac on. now everything is working fine.

before i make any more changes, my question is, how i can make My NAT type say OPEN on codmw2 without “crashing” or affecting everything else on our network? 

thank u so much