Can you draw a diagram? It kind of sounds like you need either NAT or VPN or a combination of the two.
Sounds like he's behind a double NAT and wants a public IP
I don't think double NAT is my case. My ISP doesn't provide me with a public IP.
Excuse my amateur drawing..
I agree with the double nat on the adsl side. If you have a private IP and still have internet it's behind a NAT. You need a public IP on the top right. When you say forward traffic what type of traffic is being sent? Do you want it relayed or are you ingesting it and manipulating it in some way? I guess what is the server in top left doing with it before it goes to game server at top right? A simple route would pass this traffic from server to game server at the routing level.
I cannot acquire a public ip on the top right, it is nearly impossible. Forwarded traffic will mostly be straight TCP and UDP traffic. The server at the top left must only forward all traffics to top right network somehow. It should not modify anything. I just need to make use of that public ip from my private network.
Tailscale to connect everything. Then in the public server use a reverse proxy (nginx proxy manager or swag) and point it to the tailscale IP of the server you want out.
Thanks for the reply! I will research it a bit, I still lack tons of knowledge about networking, yet still learning.
The above comment is right, use Tailscale or something similar. If you are interested in knowing more, search up "NAT transversal".
But my experience suggests that those solutions may introduce quite a bit of latency, which is probably not desirable when you are running a game server. If you have IPv6, take advantage of it and let the ADSL2 router connect to your forward server using IPv6.
So, I can receive incoming traffic using IPv6 despite I don't even have a public ip? (nv my ISP doesn't support IPv6)
If you have IPv6 connection and the address starts with "2", then your public address is the IPv6 address.
Nope it just doesn't support it. I tinkered a bit in router config enabling IPv4/IPv6. But didn't get IPv6 address from ISP. Still using ADSL2+
Community for discussing enterprise networks and the ensuing chaos that comes after inheriting or building one.