Well you can always add a constant number to the actual port number used by the games (to remap it) whenever a socket trying to connects or listens to a certain port (as a PPSSPP-specific multiplayer-mode).
This will prevent the game using privileged ports but making PPSSPP to be incompatible with real PSP or other emulators, but at least PPSSPP vs PPSSPP should works.
This will prevent the game using privileged ports but making PPSSPP to be incompatible with real PSP or other emulators, but at least PPSSPP vs PPSSPP should works.
PPSSPP Multiplayer Guide: https://github.com/hrydgard/ppsspp/wiki/How-to-play-multiplayer-games-with-PPSSPP