Information
Controlling LAN access via 802.1x authentication can assist in preventing a malicious user from connecting an unauthorized PC to a switch port to inject or receive data from the network without detection.
Solution
Configure 802.1 x authentications on all host-facing access switch ports. To authenticate those devices that do not support 802.1x, MAC Authentication Bypass must be configured.
Step 1: Configure the radius servers as shown in the example below:
SW1(config)# radius-server host 10.1.1.1 key xxxx
SW1(config)# radius-server host 10.2.1.1 key xxxx
Step 2: Enable 802.1x authentication on the switch.
SW1(config)# aaa group server radius RADIUS_GROUP
SW1(config-radius)# server 10.1.1.1
SW1(config-radius)# server 10.2.1.1
SW1(config-radius)# exit
SW1(config)# aaa authentication dot1x default group RADIUS_GROUP
SW1(config)# exit
Step 3: Enable 802.1x on all host-facing interfaces as shown in the example below:
SW1(config)# int e1/1 - 80
SW1(config-if-range)# dot1x port-control auto
SW1(config-if-range)# dot1x host-mode single-host
SW1(config-if-range)# end
Note: Host-mode must be set to single-host, multi-domain (for VoIP phone + PC), or multi-auth (multiple PCs connected to a hub). Host-mode multi-host is not compliant with this requirement.