Hello!

I hope this is the right forum to ask.
I've been trying to play Jazz2 CO-OP on GOG Galaxy with a friend.

Problem is I can create the server but my friend can't join. the server name is listed but it says "pinging" next to it and won't let him connect. He tired to host it instead but the same problem.
There's a prompt at the bottom to write an address. We tried our IP addresses but that only created another server with that address as the name ans still stuck "pinging".

I've tried to find a solution but no luck. The GOG forums are very sparse on Jazz2 info so I thought I'd have better luck here.

What am I doing wrong?

Hello! You can read an article about how to solve this here. If you're already familiar with port forwarding on your router, you need ports 10052-10054; otherwise, the full article will explain.

Thank you for the fast reply!

Unfortunately my server still shows up as "pinging" to my friend.

Can you please review the virtual server I configured?
Interface Name: pppoe_0_0
Service Type: SOCK
External Port: 80
Internal IP: ***.***.1.1
Internal Port: 10052 (Should I maybe write the GOG Galaxy client Service instead? Though it seems to change periodically)
Protocol: ALL (TCP and UDP)

10052-10054 is a range: you want 10052, 10053, and 10054, not just one of them. The GOG Galaxy service isn't relevant.

Other than the port numbers, this issue and solution are not specific to JJ2 - online games with decentralized user-hosted servers, e.g. Minecraft, generally require the host to forward ports for clients to be able to connect. Unfortunately, increasingly many ISPs employ an approach called CGNAT, which prevents port forwarding from having an effect. If all you want is to play with a friend and you find that you have no luck with port forwarding, you may want to try software such as Hamachi or ZeroTier - just read up on them online and make sure you and your friend know what you're installing.

Thank you both for the help!
Alas my ISP does indeed have CGNAT so I'll have to emulate LAN with one of the recommended Apps.
Just as well because my router didn't allow for a range of values for the internal port. No symbols other than numbers were allowed, not even spaces. Leaving it empty would just add 80 automatically like the external port.
I thought maybe the firewall on my anti-virus was to blame but even after turning off the anti-virus, firewall and all, it still would not take.

But thanks once again for your help.