Chapter 3: Featuring Configuration
– Web UI
Featuring Configuration
– Web UI
NGSM48T2 User Manual | 77
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 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 -
