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need to know which authentication method the supplicant and the authentication server are using, or how many information
exchange frames are needed for a particular method. The switch simply encapsulates the EAP part of the frame into the
relevant type (EAPOL or RADIUS) and forwards it.
When authentication is complete, the RADIUS server sends a special packet containing a success or failure indication. Besides
forwarding this decision to the supplicant, the switch uses it to open up or block traffic on the switch port connected to the
supplicant.
Overview of MAC-based Authentication
Unlike 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 static entries into the MAC Table. 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 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 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, and only the MD5-Challenge method is supported.
The 802.1X and MAC-Based Authentication configuration consists of two sections, a system- and a port-wide.
Overview of User Authentication
It is allowed to configure the Managed Switch to authenticate users logging into the system for management access using local
or remote authentication methods, such as telnet and Web browser. This Managed Switch provides secure network
management access using the following options:
Remote Authentication Dial-in User Service (RADIUS)
Terminal Access Controller Access Control System Plus (TACACS+)
Local user name and Privilege Level control
RADIUS and TACACS+ are logon authentication protocols that use software running on a central server to control access to
RADIUS-aware or TACACS-aware devices on the network. An authentication server contains a database of multiple user
name / password pairs with associated privilege levels for each user that requires management access to the Managed Switch.
User's Manual of GS-5220-24T4XV(R) Managed LCD Switch
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