changing my ps3 type to type 2 or 1

I am having the hardest time changing my ps3 connectivity. I currently have a type 3 connection. I have tried changing the dmz to the ps3's ip adress, disabling router firewall, opening ports to ps3, and other various things. I currently have a belkin router model f7d2301 v1...and have it on the dynamic setting. I have no idea how to change it to static. My isp is AT&T. Any suggestions from changing it to (at least) nat type 2? Thanks in advance...