D-Link DFL-600 - Manual (Page 46)

Clicking on the Edit link (which appears when you enable 802.1x) will open
the 802.1x Device Configuration page, as shown below.
If you have PCs on your LAN that do not require RADIUS user
authentication to access the Internet (or other networks through your ISP),
you can use Enable 802.1x, and then click the Edit link. This will allow you
to enter the IP Address and IP (subnet) Mask of PCs on your LAN that need
to bypass the RADIUS user authentication. PCs (and network devices)
whose IP Addresses and IP (subnet) Masks are entered on the 802.1x Device
Configuration page will be allowed to access the Internet without RADIUS
user authentication