Main Screen (Explorer View).          Router Info.

EchoLink Setup & Preferences

D-Link   Model DI-614+ Firewall settings.   Note there are 3 for EchoLink.
UDP 5198 & 5199, TCP 5200.
This Example allows 4 PCs to connect to these Ports via this Router.
The Intent is to allow just one PC at a time to be running EchoLink software through your Router.