I'm not sure if this is the right place to post this issue instead of in technical help since this is more aimed towards multiplayer.
Feel free to move if this fits better in the technical help section.
I'm trying to host a linux headless server. I get the server up and running with no problems. I can even connect to it using my localhost ip. No problems here. So I went ahead and port-forwarded the default factorio port and asked one of my friends to try connecting to the server. They can't connect. So I started using nmap to check out if I can ping to my server using the default factorio port. The result of this ping was that the port is filtered and the reason why is that it doesn't receive a response. I also tried using ports I had open in the past. For example the default minecraft server port ( 25565) also filtered. I double checked if I am portforwarding the ports of the right computer on the network. I already did several restarts of the router.
Port setup
Is there anyone who has an idea of what I might be doing wrong? 
Thanks in advance
Edit: nvm I am an idiot. This checkbox actually means that it is enabled or disabled. Strange interface.