D-Link DNR-4020-16P User Manual page 126

Section 3 - Configuration
Port Number
On this page you can set the ports that the NVR will use to transfer data and allow
clients to connect to.
The HTTP port for the web UI.
HTTP Port
The port that data will be transferred over. The port that client devices
Data Port
will connect to.
It is necessary to reboot the device after modifying any of the
Client Port
port configuration settings.
D-Link DNR-4020-16P User Manual 121