Installation guide

Configuring the Switch
3-28
802.1X
Network switches can provide open and easy access to network resources by
simply attaching a client PC. Although this automatic configuration and access 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 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 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., 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 encryption method used to pass authentication
messages can be MD5 (Message-Digest 5), TLS (Transport Layer Security), or
TTLS (Tunneled Transport Layer Security). 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 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.
• The IP address of the RADIUS server must be specified.
• 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 have dot1x client software
installed and properly configured.
• The RADIUS server and client also have to support the same EAP authentication
type – MD5. (Some clients have native support in Windows, otherwise the dot1x
client must support it.)