D-Link DFL-600 - Manual (Page 45)

RADIUS server will use to connect to PCs on
your LAN for the RADIUS accounting function.
The default port number for accounting is 1813.
Secret Key Enter the shared key used between PCs on your
LAN and the RADIUS server.
Accounting Service Use the drop-down menu to enable or disable the
RADIUS accounting service.
Authentication
Method Use the drop-down menu to enable or disable the
RADIUS accounting service.
Clicking the 802.1x Enable click-box, and then Edit link will open the
following page:
802.1x is a standard for passing the Extensible Authentication Protocol
(EAP) packets over a LAN. You should enable this if there are any 802.1x
devices between the DFL-600 and the RADIUS server on the WAN.