System information

2-93
Configuring 802.1x Port Authentication
2
The IEEE 802.1x (dot1x) standard defines a port-based access control procedure
that prevents unauthorized access to a network by requiring users to first submit
credentials for authentication. Access to all switch ports in a network can be
centrally controlled from a server, which means that authorized users can use the
same credentials for authentication from any point within the network.
This switch uses the
Extensible Authentication
Protocol over LAN
(EAPOL) with MD5
authentication to
exchange authentication
protocol messages with
the client, and a remote
RADIUS authentication
server to verify user
identity and access rights.
When a client (i.e.,
Supplicant) connects to a
switch port, the switch (i.e., Authenticator) responds with an EAPOL identity request.
The client provides its identity (such as a user name) in an EAPOL response to the
switch, which it forwards to the RADIUS server. The RADIUS server verifies the
client identity and sends an access challenge back to the client. The EAP packet
from the RADIUS server contains not only the challenge, but the authentication
method to be used. The client can reject the authentication method and request
another, depending on the configuration of the client software and the RADIUS
server. The authentication method must be MD5. The client responds to the
appropriate method with its credentials, such as a password or certificate. The
RADIUS server verifies the client credentials and responds with an accept or reject
packet. If authentication is successful, the switch allows the client to access the
network. Otherwise, network access is denied and the port remains blocked.
The operation of dot1x on the switch requires the following:
• The switch must have an IP address assigned.
• Logon authentication (page 2-12) must be enabled on the switch and the IP
address of the authentication server specified.
• Each switch port that will be used must be set to dot1x “Auto” mode.
• Each client that needs to be authenticated must have dot1x client software
installed and properly configured.
Displaying 802.1x Global Settings
The dot1x protocol includes global parameters that control the client authentication
process that runs between the client and the switch (i.e., authenticator), as well as
802.1x
client
RADIUS
server
1. Client attempts to access a switch port.
2. Switch sends client an identity request.
3. Client sends back identity information.
4. Switch forwards this to authentication server.
5. Authentication server challenges client.
6. Client responds with proper credentials.
7. Authentication server approves access.
8. Switch grants client access to this port.