YAST2 -> Firewall -> Custom Rules -> Add ->
Source Network is where you want the connection be allowed from, 0/0 means port is open FROM ALL IP addresses.
Protocol is TCP
Destination port is 4644
Source and Additional you can ignore.
You have to create another rule for UDP separately.
And the port number is what I got from Google - it might not be 100% certain as I do not use this application myself.