nmap on local host shows "filtered" on port which is stated as "open" on remote host

mn flag

My question is similar to this but I'd like to fix and understand the error without having to rely on the possibility that factory-resetting my router will fix it for me. I also found this which is about the same problem but left unanswered. There seems to be a hidden issue others and me must be missing.

I want to reach an ubuntu 20.04 server with my local zorin 16 machine. The server is hosting a minecraft server (this is irrelevant to this question, it only explains why i need port 25565) within my LAN. I ran

$ sudo ufw allow 25565/tcp

on both of them. Checking

$ nmap localhost -p 25565

on the server reveals that the port is open, while calling the server from the main machine with

$ nmap -p 25565

just shows filtered. Both firewalls are active and allow tcp traffic through port 25565. From my limited understanding, nothing seems wrong, yet here i am not being able to connect to the server. What could be wrong?

Edit: Also, when looking at ufw status it looks like the configuration for a working port like 22 is set up the exact same way as 25565. Could it be that another app like iptables is messing with my config behind the scenes?

Edit: Running the server with or without sudo does not change anything.

David avatar
cn flag
What is the version of Ubuntu being used?
jake_asks_short_questions avatar
mn flag
@David 20.04 Focal Fossa

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