And I didn't even mention how some ISP's block ports below 1024 (thus ssh, ftp and web standard ports cannot be used to accept incoming connections even if you are connected to the WAN or did the port forwarding correctly).
That pretty much is (or was, not sure how most games currently handle networking) the main frustration of setting up a game server at home for your friends at their homes.
One solution back then was to use Hamachi to create a "virtual lan network". Btw for some use-cases you could even use "ssh -L <local port>:<remote computer>:<remote port> <user>@<remote ip>" with a server, and certainly nowadays you can get a vps at 12$/year (nothing fancy, but good enough for tunnelling ports).
That pretty much is (or was, not sure how most games currently handle networking) the main frustration of setting up a game server at home for your friends at their homes.
One solution back then was to use Hamachi to create a "virtual lan network". Btw for some use-cases you could even use "ssh -L <local port>:<remote computer>:<remote port> <user>@<remote ip>" with a server, and certainly nowadays you can get a vps at 12$/year (nothing fancy, but good enough for tunnelling ports).
Hamachi: https://en.wikipedia.org/wiki/Hamachi_(software)