Instructions
Turn on your PS3 console and log in to your gaming profile. Scroll through the guide menus to ̶0;Internet Browser̶1; and click on it.
Press the ̶0;Start̶1; button on your PS3 controller to select the address bar and then type the router̵7;s configuration address into the text field. If you don̵7;t know it offhand, the configuration address of your router can be found in its documentation. Type your user name and password when prompted.
Click on the ̶0;WAN Setup̶1; or similarly named category to open it and then select the ̶0;Secured̶1; option in the ̶0;NAT Filtering̶1; section of the page. Click ̶0;Apply̶1; to close your NAT filter setting on your PS3. Log out of your router configuration; you can now play online PS3 games securely.