KTI Networks KGS-1064-HP User Manual page 60

aren't authenticated. To overcome this security breach, use the Multi 802.1X variant.
Multi 802.1X is really not an IEEE standard, but features many of the same
characteristics as does port-based 802.1X. Multi 802.1X is - like Single 802.1X - not
an IEEE standard, but a variant that features many of the same characteristics. In
Multi 802.1X, one or more supplicants can get authenticated on the same port at the
same time. Each supplicant is authenticated individually and secured in the MAC
table using the Port Security module.
In Multi 802.1X it is not possible to use the multicast BPDU MAC address as
destination MAC address for EAPOL frames sent from the switch towards the
supplicant, since that would cause all supplicants attached to the port to reply to
requests sent from the switch. Instead, the switch uses the supplicant's MAC address,
which is obtained from the first EAPOL Start or EAPOL Response Identity frame
sent by the supplicant. An exception to this is when no supplicants are attached. In
this case, the switch sends EAPOL Request Identity frames using the BPDU
multicast MAC address as destination - to wake up any supplicants that might be on
the port.
The maximum number of supplicants that can be attached to a port can be limited
using the Port Security Limit Control functionality.
MAC-based Auth.: Unlike port-based 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 on 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 the Port Security module. Only then will frames from the
client be forwarded 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 port-based 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 don't need special
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