Configuring Port-Based and Client-Based Access Control (802.1X)

Configuring Switch Ports To Operate As Supplicants for 802.1X Connections to Other Switches

■Switch “A” has port A1 configured for 802.1X supplicant operation

■You want to connect port A1 on switch “A” to port B5 on switch “B”.

Switch “B”

Port B5

Port A1

Switch “A”

Port A1 Configured as an

802.1X Supplicant

LAN Core

RADIUS Server

 

Figure 8-6. Example of Supplicant Operation

1.When port A1 on switch “A” is first connected to a port on switch “B”, or if the ports are already connected and either switch reboots, port A1 begins sending start packets to port B5 on switch “B”.

•If, after the supplicant port sends the configured number of start request packets, it does not receive a response, it assumes that switch “B” is not 802.1X-aware, and transitions to the authenticated state. If switch “B” is operating properly and is not 802.1X-aware, then the link should begin functioning normally, but without 802.1X security.

•If, after sending one or more start request packets, port A1 receives a request packet from port B5, then switch “B” is operating as an 802.1X authenticator. The supplicant port then sends a response/ID packet. If switch “B” is configured for RADIUS authentication, it forwards this request to a RADIUS server. If switch “B” is configured for Local 802.1X authentication (page 8-23),the authenticator com- pares the switch “A” response to its local username and password.

2.The RADIUS server then responds with an access challenge that switch “B” forwards to port A1 on switch “A”.

3.Port A1 replies with a hash response based on its unique credentials. Switch “B” forwards this response to the RADIUS server.

4.The RADIUS server then analyzes the response and sends either a “suc- cess” or “failure” packet back through switch “B” to port A1.

•A “success” response unblocks port B5 to normal traffic from port A1.

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