User Manual

FGSW-2620VM / FGSW-2624SF User’s Manual

4.5.1 802.1x/Radius

Understanding IEEE 802.1X Port-Based Authentication

The IEEE 802.1X standard defines a client-server-based access control and authentication protocol that restricts

unauthorized clients from connecting to a LAN through publicly accessible ports. The authentication server

authenticates each client connected to a switch port before making available any services offered by the switch or the

LAN.

Until the client is authenticated, 802.1X access control allows only Extensible Authentication Protocol over LAN (EAPOL)

traffic through the port to which the client is connected. After authentication is successful, normal traffic can pass through

the port.

This section includes this conceptual information:

• Device Roles

• Authentication Initiation and Message Exchange

• Ports in Authorized and Unauthorized States

 Device Roles

With 802.1X port-based authentication, the devices in the network have specific roles as shown below.

z Client—the device (workstation) that requests access to the LAN and switch services and responds to

requests from the switch. The workstation must be running 802.1X-compliant client software such as that

offered in the Microsoft Windows XP operating system. (The client is the supplicant in the IEEE 802.1X

specification.)

z Authentication server—performs the actual authentication of the client. The authentication server validates

the identity of the client and notifies the switch whether or not the client is authorized to access the LAN and

switch services. Because the switch acts as the proxy, the authentication service is transparent to the client. In

this release, the Remote Authentication Dial-In User Service (RADIUS) security system with Extensible

Authentication Protocol (EAP) extensions is the only supported authentication server; it is available in Cisco

Secure Access Control Server version 3.0. RADIUS operates in a client/server model in which secure

authentication information is exchanged between the RADIUS server and one or more RADIUS clients.