Table of Contents
Advertisement
Security | Network | NAS | Switch
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 - 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 attached to a
port can be limited using the Port Security Limit Control functionality.
206 - Monitor Pages
RocketLinx MP1204-XT User Guide: 2000644 Rev. A
Advertisement
Table of Contents
