RFC 4014 RADIUS Attributes Suboption

The RADIUS Attributes suboption for the DHCP Relay Agent option provides a way in which a NAS can pass attributes obtained from a RADIUS server to a DHCP server [1]. IEEE 802.1X [2] is an example of a mechanism through which a NAS such as a switch or a wireless LAN access point can authenticate the identity of the user of a device before providing layer 2 network access with RADIUS as the Authentication Service, as specified in RFC 3580 [8]. In IEEE 802.1X authenticated access, a device must first exchange some authentication credentials with the NAS. The NAS then supplies these credentials to a RADIUS server, which eventually sends either an Access-Accept or an Access-Reject in response to an Access-Request. The NAS, based on the reply of the RADIUS server, then allows or denies network access to the requesting device.