Black Box LE2700A, User Manual, Page: 108 / 154

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Page 108
Chapter 5: Management
Overview of MAC-Based Authentication
Unlike 802.1X, MAC-based authentication is not a standard, but merely a best-practices method adopted by the industry. In MAC-
based authentication, users are called clients, and the switch acts as the supplicant on behalf of clients. The initial frame (any kind
of frame) sent by a client is snooped by the switch, which in turn uses the client's MAC address as both username and password
in the subsequent EAP exchange with the RADIUS server. The 6-byte MAC address is converted to a string in the following form
"xx-xx-xx-xx-xx-xx", that is, a dash (-) is used as separator between the lower-cased hexadecimal digits. The switch only supports
the MD5-Challenge authentication method, so the RADIUS server must be configured accordingly.
When authentication is complete, the RADIUS server sends a success or failure indication, which in turn causes the switch to open
up or block traffic for that particular client, using static entries into the MAC Table. Only then will frames from the client be for-
warded on the switch. There are no EAPOL frames involved in this authentication, and therefore, MAC-based authentication has
nothing to do with the 802.1X standard.
The advantage of MAC-based authentication over 802.1X is that several clients can be connected to the same port (e.g. through a
3rd party switch or a hub) and still require individual authentication, and that the clients do not need special supplicant software
to authenticate. The disadvantage is that MAC addresses can be spoofed by malicious users, equipment whose MAC address is a
valid RADIUS user can be used by anyone, and only the MD5-Challenge method is supported.
802.1X and MAC-Based authentication configurations consist of two sections: system- and port-wide.
Figure 5-100. Network Access Server Configuration screen.