This is what I’ve done on my router website:

And on Manjaro Linux:

❯ sudo systemctl enable --now ufw.service
❯ sudo ufw enable
  # NicotinePlus
❯ sudo ufw allow 2234/tcp
  # eMule
❯ sudo ufw allow 4662/tcp
❯ sudo ufw allow 4663/tcp
❯ sudo ufw allow 4664/tcp
❯ sudo ufw allow 4665/udp
❯ sudo ufw allow 4672/udp
❯ sudo systemctl restart ufw.service
❯ sudo ufw status
Status: active

To                         Action      From
--                         ------      ----
2234/tcp                   ALLOW       Anywhere
4662/tcp                   ALLOW       Anywhere
4663/tcp                   ALLOW       Anywhere
4664/tcp                   ALLOW       Anywhere
4665/udp                   ALLOW       Anywhere
4672/udp                   ALLOW       Anywhere
2234/tcp (v6)              ALLOW       Anywhere (v6)
4662/tcp (v6)              ALLOW       Anywhere (v6)
4663/tcp (v6)              ALLOW       Anywhere (v6)
4664/tcp (v6)              ALLOW       Anywhere (v6)
4665/udp (v6)              ALLOW       Anywhere (v6)
4672/udp (v6)              ALLOW       Anywhere (v6)

edit:

maycne.sonahoz

By default, on Linux, listening ports are closed unless you actually have a program actively listening to them. So there is no need to explicitly start a firewall and “open” them.

By default, on Linux, listening ports are closed unless you actually have a program actively listening to them. So there is no need to explicitly start a firewall and “open” them.

Testing gives an error: http://porttest.emule-project.net:81/ct_frame.php?lang=1036&tcpport=64121

Please wait while the ports of your eMule are being tested...


Testing IP: (xxx.xxx.xxx.xxx)

Obfuscation: Disabled

Starting TCP connection test...
TCP test failed! UDP test will not be performed.


Connection test finished.

Results in detail:

    TCP connection test failed.
    It was not possible, to establish a TCP connection to your eMule.
    Other users will only be able to connect to you with the help of a server, resulting in a low ID for you. While eMule still works, this will give you several disadvantages. Therfore it is highly recommended to solve this problem.

 
How to resolve port problems... Something is interfering with your network communications. There are two main reasons for this:

    If you are using a firewall, ensure that your firwall don't block the required ports! You might need to set a rule to allow the ports to be available.
    If you use a router, make sure that your router forwards the required ports to your local IP!


    You can find more details and guides [here in the online help.](http://www.emule-project.net/home/perl/help.cgi?rm=show_entries&cat_id=232)