D-Link DSL-2790U User Manual page 51

Configuration
Some applications such as games, video conferencing, remote access
applications and others require that specific ports in the Router's firewall be
opened for access by the applications. You can configure the port settings from
this screen by selecting an existing application or creating your own (Custom
application).
Click the Add button to configure port triggering.
You can configure the port settings on this window by clicking the Select an
application radio button and then using the drop-down list to choose an existing
application, or by clicking the Custom application radio button and entering
your own Application Rule in the field provided.
Click Save/Apply when you are finished with the port setting configuration. The
new Application Rule will appear in the Port Triggering table.
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