Authenticator) responds with an EAPOL identity request. The client provides its
identity (such as a user name) in an EAPOL response to the switch, wh ich 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 an d reque st another, depend ing on
the configuration of the client software and the RADIUS server. The authent ication
method must be MD5. (TLS, TTLS and PEAP will be supported in future releases.)
The client responds to the appropriate method with its credentials, such as a
password or certificate. The RADIUS server verifies the client cre dentia ls 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.
• The IP address of the RADIUS server must be specifi ed.
• 802.1X must be enabled globally for the switch.
• Each switch port that will be used must be set to dot1x “Auto” mode.
• Each client that needs to be authenticated must hav e dot1x cli ent softwa re
installed and properly configured.
• The RADIUS server and 802.1X client support EA P. (The switch on ly support s
EAPOL in order to pass the EAP packets from the server to the client.)

6-18

Configuring 802.1X Port Authentication
Network switches can provide open and easy access to network resource s by
simply attaching a client PC. Although this automatic configuration and acce ss is a
desirable feature, it also allows unauthorized personnel to easily intrude and
possibly gain access to sensitive network data.
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 su bmit
credentials for authentication. Access to all switch ports in a netwo rk 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
User Authentication

6
Protocol over LANs (EAPOL)
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.,
802.1
x
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.