What is making my ps3 unable to connect to game sessions online?

Every online game I have tried(skate, mlb 2k8, and battlefield 1943) will not connect online to other game sessions. My NAT type is 2 and i have a solid internet connection. I can send messages and browse the web but playing online doesn't work. I have tried all sorts of alterations to my internet connection to fix this but nothing works. Any suggestions?What is making my ps3 unable to connect to game sessions online?Some games server has difficulties on trying to reach online, especially for Battlefield 1943. Happen to me too.