Planet GS-5220 Series, Руководство пользователя, Страница: 377 / 568

User’s Manual of GS-5220 LCD Series
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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.
InMAC-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 supplicant software to
authenticate. The advantage of MAC-based authentication over
802.1X-based authentication is that the clients don't 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. Also, only the