Trying to set up multiplayer with roommate

[fitzavig]

Room mate here. I don't disregard some of your suggestions because you lack "expertise". In fact, remember how I was quite happy when you brought up a blind spot on my radar about port offsets? How I immediately ran off to test this theory of yours with gusto? I may disregard other ideas because the suggestion lacks merit. Once again (for example), Hamachi on a LAN is basically a redundancy that complicates things potentially. Not using it would prevent redundancy and potential for complications. From a diagnostic standpoint, this is why I shot the idea down, but even so, we still keep using it don't we? I'm trying such suggestions (that don't fix it) for your learning experience here since you clearly doubt what knowledge I do have on the subject.

Now that that's cleared up, allow me to get to why I'm actually here:

As my room mate has pointed out, we have attempted likely dozens of times to get this to work on a LAN between a windows (Win10?) and linux (Arch Linux) machine. The game in question is Phantasy Star Portable 2.

Given his claims that two windows machines running 1.0.1 can connect and play together, it would seem the onus switches from both to the linux machine. Following that thread, it strikes me as odd that linux itself would be the issue as I use many networking applications any given moment. PPSSPP would be the outlier there, but then what could be causing it? I assume PPSSPP uses the SDL2 networking features to do its thing. This is odd since I would also assume that SDL2, being cross-platform, would provide feature parity between platforms (that's kind of its thing). This could be construed as PPSSPP's code is somehow mishandling SDL2's networking features, but then why the difference between platforms? This train of thought appears to be a dead end to my eyes unless SDL2 for linux itself is the problem.

Looking at it as a network problem, I find even less to analyze. We've seemingly solved the port problem and the client gets a "Network Initialized" message. This suggests that the connection is sound. Why then does PPSSPP connect, but PSP2 doesn't show any parties in the adhoc multiplayer? Yet another dead end?

Lastly, perhaps this is something specific to how PSP2 handles networking? If it's nonstandard in some way (as games occassionally do) then perhaps this is throwing PPSSPP off? Still doesn't explain the success of the 1.0.1 machines though..

End of the day, however, I'm spitballing about what could be the cause. These are the main schools of thought I'm following and coming up with nothing. An extra set of eyes would be excellent since if there is a simple solution, we've clearly overlooked it multiple times.

Also, thanks for the help so far! While it isn't solved, I feel a "yet" is very much going to be the case here with the prompt responses so far. You guys are great!