Just wanted to post this as info to other RV220w users that have a playstation 3. By default a setting is on in the firewall that blocks fragmented packets.. With this setting on even if the ps3 is in the dmz some games wont work and if you test the ps3 connection it will tell you that either your router or service provider doesn't allow fragmented packets. Its under Firewall > Attack Prevention > check box "block fragmented packets".
the error from testing connection on ps3 is
The router in use may not support IP fragments, and the communication features of some games may be restricted.