Draytek 5500 Series manual Private Port, Active

	box (as the starting point). The second one is assigned
	automatically after you type the private port number below.
Private Port	Specify the private port number of the service offered by the
	internal host. After you enter the proper number in this box, the
	second box of Private IP address will be assigned accordingly.
Active	Check this box to activate the port-mapping entry you have
	defined.

Note that the router has its own built-in services (servers) such as Telnet, HTTP and FTP etc. Since the common port numbers of these services (servers) are all the same, you may need to reset the router in order to avoid confliction.

For example, the built-in web configurator in the router is with default port 80, which may conflict with the web server in the local network, http://192.168.1.13:80. Therefore, you need to change the router’s http port to any one other than the default port 80 to avoid conflict, such as 8080. This can be set in the System Maintenance >>Management Setup. You then will access the admin screen of by suffixing the IP address with 8080, e.g., http://192.168.1.1:8080 instead of port 80.

VigorPro5500 Series User’s Guide 45