Why does Multiplay require bindable ports?
Clanforge generates port numbers dynamically per server instance with a configurable offset. To leverage this functionality, your server instance must support configurable ports (for example, accept the port number via a command-line argument). By using dynamic ports, you’ll prevent port conflicts between your game server instances.
Multiplay does not block any ports in the range 8100 to 65355. Your server instance should only use ports in this range.