802.1X Configuration; Understanding Ieee 802.1X Port-Based Authentication - Interlogix GE-DS Series User Manual

802.1X Configuration

802.1x is an IEEE authentication specification which prevents the client from accessing a wireless access point or wired switch
until it provides authority, like the user name and password that are verified by an authentication server (such as RADIUS
server).

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.
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.)
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.
 Switch (802.1X device)—controls the physical access to the network based on the authentication status of the client.
The switch acts as an intermediary (proxy) between the client and the authentication server, requesting identity
information from the client, verifying that information with the authentication server, and relaying a response to the client.
The switch includes the RADIUS client, which is responsible for encapsulating and decapsulating the Extensible
Authentication Protocol (EAP) frames and interacting with the authentication server. When the switch receives EAPOL
frames and relays them to the authentication server, the Ethernet header is stripped and the remaining EAP frame is
re-encapsulated in the RADIUS format. The EAP frames are not modified or examined during encapsulation, and the
authentication server must support EAP within the native frame format. When the switch receives frames from the
authentication server, the server's frame header is removed, leaving the EAP frame, which is then encapsulated for
Ethernet and sent to the client.

Authentication Initiation and Message Exchange
The switch or the client can initiate authentication. If you enable authentication on a port by using the dot1x port-control auto
GE-DS-82 and NS2503-8P/2C Series User Manual
Figure 4-12-1: 802.1x device role
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