Understanding 802.1X Port-Based Authentication - Cisco WS-C3550-12G Software Configuration Manual

Configuring 802.1X Port-Based Authentication
This chapter describes how to configure IEEE 802.1X port-based authentication to prevent unauthorized
devices (clients) from gaining access to the network. As LANs extend to hotels, airports, and corporate
lobbies, insecure environments could be created.
For complete syntax and usage information for the commands used in this chapter, refer to the
Note
Catalyst 3550 Multilayer Switch Command Reference for this release.
This chapter consists of these sections:
Understanding 802.1X Port-Based Authentication, page 7-1
•
• Configuring 802.1X Authentication, page 7-5
Displaying 802.1X Statistics and Status, page 7-14
•

Understanding 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, page 7-2
•
Authentication Initiation and Message Exchange, page 7-3
•
Ports in Authorized and Unauthorized States, page 7-4
•
Supported Topologies, page 7-4
•
78-11194-03
C H A P T E R
Catalyst 3550 Multilayer Switch Software Configuration Guide
7
7-1