Well the dedicated server doesn't appear to be ready yet for this mod, but excited to see how it progresses. For now, I think the listen server (i.e. host is in-game) should work over Internet now as long as ports forwarded/firewall unblocked. May preclude being able to alter runspeed/respawn scale (although it has a console now with the tidle ~ key, have to experiment with that)!
Viewing post in No One Lives Forever 2 - Modernizer comments
Yeah listen servers should work. There's no port punch through, so like you said criminalcola (good name btw), otterr (and others) have to open the ports!
I need to do some further work to stabilize things a bit. I had to re-write the entire server browser back-end (and adjust my basic gamespy emulator) for NOLF 2 (For nolf1 I was able to just hex edit the server address, there were a lot more dependencies in NOLF 2 that made that impossible.)
If you're interested in multiplayer make sure to check out https://www.spawnsite.net and their discord. They host weekly multiplayer matches on weekends. (For NOLF1, probably NOLF2 as well if you ask!)