What ports does the ad hoc server utilize?

[MHP3rd]

(11-29-2016 06:18 AM)tywald Wrote:  Ad hoc server uses TCP port 27312 which I think you already know, in the case of PPSSPP:

One way to see some ports is to open up Resource Monitor and see the "Listening Ports" tab. Start a game and join a lobby and it should show at least one, for Monster Hunter it should show UDP port 10000. If you enter a quest more ports should show up, in the case of Monster Hunter UDP ports 20001-20004 should show up.

It's a start at least.

Thanks for your help.
I went ahead and opened ports 27312, 10000 and ports 20001-20004.
If I try connecting using my local IP (laptop and desktop on the same LAN network), everything works just as expected.
Using my external IP does not work, however.
If I try to connect to the server on a different machine using the external IP, it connects, but I can't see the character playing on the server machine in the lobby.

The client crashes if I attempt to go online while the server is down, but works if it's up, so there is clearly some connection there.
Am I correct in assuming that I can connect to the server running on the same machine using either 127.0.0.1, the local IP, or the external IP?

Any tips on where I can go from here?