This is going to give you a small and simple run down on how to fix your nat to be opened! Moderate and Strict are HORRIBLE to try to play with so fix your NAT!
1. Setup a static IP address on your PS3. Here is a video how: http://www.youtube.com/watch?v=i31YP65tl7w BTW thats not me! lol.
2. Go to www.portforward.com and select your router/modem and then select CoD W@W or CoD 4 and enter your ports into your router OR you can DMZ your PS3's IP address that we already made a static IP on.
3. Now go into your router via explorer and turn on UPnP. ALWAYS leave NAT ON!
4. Now go to your PS3 Network settings and edit your connection manually.
5. Leave your static IP address and DNS's alone, But on MTU set it to 1500 and turn on UPnP.
6. Save and exit and then you can test and either you should have a Nat 2 or 1.
Now this fixed about 5/7 of my clan members nat lastnight and I hope that it does the same for you guys as well. Mine was Moderate and it was taking forever to get into a game and once I applyed these settings and rebooted the PS3 and power cycled my router BAM! OPEN NAT! ALSO please remember to power cycle your router and Modems at least 1 TIME a WEEK! Day is better. Power cycle is turning it off and leaving it off for at least 15 mins and then rebooting. I hope that everyone finds this information helpful. LMK!