I have a server running a minecraft server. It's configured to work on port 25565.
In my router, I've forwarded port 25565 to the server, port 25565. Simple forward.
Internally I can log in just fine (with and without port, by specifying the server's local IP). CanYouSeeMe.org says the port is open, but I cannot log in using the external IP (with and without port, no difference).
We found out through an nmap scan on my external ip, that the port is closed anyway...
ufw is disabled, I'm absolutely sure of it. Enabled firewall (ufw), ran the nmap scan again, still closed.
Do I have to call my ISP, or is this something I'm doing wrong/haven't fixed yet?
EDIT Fine, I'll add this to the question even though it's good enough for an answer for me:
Something to do with NAT loopback.
When I connected my pc with my phones' dataplan, the external IP worked like a charm.
- when I'm connected to the home network, I use the internal IP
- when I'm not at home, I use the external IP
People, I'm fucking sorry for posting in the forum where in the end it didn't belong. With the information I had (port forwarding worked, ssh'ing worked with both IP's) I thought the problem was in the server.
Go ahead, mark it as off-topic. Perhaps someone who never heard of NAT reflection either (like me) will find this topic, figure out the problem, and be helped.