I set up a Minecraft server on my Linux PC (first time, so I have little idea). It runs and I can also connect to the server via the internal address in my network. Now I wanted my friend to be able to join the server too, so I gave him my IP address and enabled port 25565 in my Fritzbox. Now the Fritzbox interface shows me that port 25565 is released as both TCP and UDP, only when I look at a port checker is it still shown to me that the port is closed. What am I doing wrong?
https://kerneltalks.com/networking/how-to-forward-port-using-iptables-in-linux/
What exactly is that supposed to help? He has a port release on a Fritzbox.
But he wrote that it will not be displayed. So why not give it a try?
Can you also connect from another device using the local address? If so, then everything works correctly on the device itself.
Have you selected the right device for port sharing? And do you use the correct public IP for testing (is in the Fritz Box web interface)? You don't need UDP by the way, Minecraft only uses TCP.
Forwarding is used to forward packets to other network adapters and possibly other ports. You need that e.g. If you set up a router or a VPN server.
If the server is operated directly on the device, forwarding on the same device is completely pointless.
