From the Advanced tab, click Continue (located on the right).
Click Port Forwarding (located below the Advanced tab, to the left).
From the Port Forwarding section, click the switch to turn on or off.
If turned on, select the desired app(s) (e.g., DNS, FTP, HTTP, etc.).
Selected when a check mark is present.
If the app isn't listed, click Add a Custom Application (lower-left) then enter the appropriate info.
If turning off Port Forwarding, skip to step 7.