User`s guide

VigorSwitch P2261 User’s Guide
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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 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 MD5-Challenge method
is supported. The maximum number of clients that can be