Under SYSTEM > Firewall > Open TCP ports: one of the ports I have is 4711. However, when I go to check if the port is open using a port checker tool such as this it's showing port 4711 is closed. I tried to add port to IP Tables iptables -A INPUT -p udp -m udp --dport 4711 -j ACCEPT without any luck. Port 4711 is still showing closed. UFW firewall is disabled on my server. I called my ISP they do not block 4711. Any suggestions how to open port 4711?