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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
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Chapter 9 Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
You can enable optional guest VLAN behavior by using the dot1x guest-vlan supplicant global
configuration command. When enabled, the switch does not maintain the EAPOL packet history and
allows clients that fail authentication access to the guest VLAN, regardless of whether EAPOL packets
had been detected on the interface.
Beginning in privileged EXEC mode, follow these steps to enable the optional guest VLAN behavior
and to configure a guest VLAN. This procedure is optional.
To disable the optional guest VLAN behavior, use the no dot1x guest-vlan supplicant global
configuration command. To remove the guest VLAN, use the no dot1x guest-vlan interface
configuration command. If the port is currently authorized in the guest VLAN, the port returns to the
unauthorized state.
This example shows how enable the optional guest VLAN behavior and to specify VLAN 5 as an
IEEE 802.1x guest VLAN:
Switch(config)# dot1x guest-vlan supplicant
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# dot1x guest-vlan 5
Configuring a Restricted VLAN
When you configure a restricted VLAN on a switch, clients that are IEEE 802.1x-compliant are moved
into the restricted VLAN when the authentication server does not receive a valid username and
password. The switch supports restricted VLANs only in single-host mode.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 dot1x guest-vlan supplicant Enable the optional guest VLAN behavior globally on the switch.
Step 3 interface interface-id Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 9-13.
Step 4 switchport mode access Set the port to access mode.
Step 5 dot1x port-control auto Enable IEEE 802.1x authentication on the port.
Step 6 dot1x guest-vlan vlan-id Specify an active VLAN as an IEEE 802.1x guest VLAN. The range is 1
to 4094.
You can configure any active VLAN except an RSPAN VLAN or a voice
VLAN as an IEEE 802.1x guest VLAN.
Step 7 end Return to privileged EXEC mode.
Step 8 show dot1x interface interface-id Verify your entries.
Step 9 copy running-config startup-config (Optional) Save your entries in the configuration file.