To change the network address translation type on a PS3, find out the current NAT type and then change it by accessing the router through the console's browser and enabling the router's UPnP function by opening up the following ports: 80, 443, 465, 983, 3478-3480, 3658, 5223, 6000-7000, 9293 and 10070-100080. These ports must be opened in both directions, for TCP and UDP, in order to facilitate the console's first party systems, like voice chat and the PlayStation Network.
With the selected ports opened properly, restarting the console will change the NAT type to the moderate NAT type, which works the best for PS3 and PS4 consoles. An open NAT type is much less secure and a strict NAT type may interfere with the console's online functions. Never open all of the ports on the router when changing a NAT type, as this can cause serious security issues.