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CHAPTER
9-1
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
9
Configuring IEEE 802.1x Port-Based
Authentication
This chapter describes how to configure IEEE 802.1x port-based authentication on the Catalyst 2950 or
Catalyst
2955 switch. IEEE 802.1x authentication prevents unauthorized devices (clients) from gaining
access to the network.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release and the “RADIUS Commands” section in the Cisco IOS Security Command
Reference, Release 12.1.
This chapter consists of these sections:
• Understanding IEEE 802.1x Port-Based Authentication, page 9-1
• Configuring IEEE 802.1x Authentication, page 9-12
• Displaying IEEE 802.1x Statistics and Status, page 9-28
Understanding IEEE 802.1x Port-Based Authentication
The IEEE 802.1x standard defines a client-server-based access control and authentication protocol that
prevents unauthorized clients from connecting to a LAN through publicly accessible ports unless they
are properly authenticated. 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, IEEE 802.1x access control allows only Extensible Authentication
Protocol over LAN (EAPOL), Cisco Discovery Protocol (CDP), and Spanning Tree Protocol (STP)
traffic through the port to which the client is connected. After authentication is successful, normal traffic
can pass through the port.
These sections describe IEEE 802.1x port-based authentication:
• Device Roles, page 9-2
• Authentication Initiation and Message Exchange, page 9-3
• Ports in Authorized and Unauthorized States, page 9-4
• IEEE 802.1x Host Mode, page 9-5
• IEEE 802.1x Accounting, page 9-6
• IEEE 802.1x Accounting Attribute-Value Pairs, page 9-6