D-Link DSL-321B User Manual page 34

Section 3 - Configuration
Type internal start port from Internal Start Port input box. It
shows the start port opened in the PC with the appointed Private
IP.
Type internal end port from Internal End Port input box. It shows
the end port opened in the PC with the appointed Private IP.
Select PVC of the port forwarding rule from Connection
drop-down list.
D-Link DSL-321B User Manual 34