Dot1X Auth-Fail Vlan - Cisco Catalyst 3550 Command Reference Manual

Chapter 2 Catalyst 3550 Switch Cisco IOS Commands

dot1x auth-fail vlan

Use the dot1x auth-fail vlan interface configuration command to enable the restricted VLAN on a port.
To return to the default setting, use the no form of this command.
Syntax Description
vlan-id
Defaults No restricted VLAN is configured.
Command Modes Interface configuration
Command History Release
12.2(25)SED
Usage Guidelines You can configure a restricted VLAN on ports configured as follows:
•
•
You should enable re-authentication. The ports in restricted VLANs do not receive re-authentication
requests if re-authentication is disabled. To start the re-authentication process, the restricted VLAN must
receive a link down event or an Extensible Authentication Protocol (EAP) logoff event from the port. If
the host is connected through a hub, the port might never receive a link down event and might not detect
the new host until the next re-authentication attempt occurs. Therefore, re-authentication should be
enabled.
If the user fails authentication, the port is moved to a restricted VLAN, and an EAP success message is
sent to the user. Because the user is not notified of the authentication failure, there might be confusion
as to why there is restricted access to the network. An EAP success message is sent for these reasons:
•
•
A user might cache an incorrect username and password combination after receiving an EAP success
message from the authenticator and re-use that information in every re-authentication. Until the user
passes the correct username and password combination, the port remains in the restricted VLAN.
Internal VLANs that are used for Layer 3 ports cannot be configured as a restricted VLAN.
You cannot configure a VLAN to be both a restricted VLAN and a voice VLAN. If you do this, a syslog
message is generated.
OL-8566-02
dot1x auth-fail vlan vlan-id
no dot1x auth-fail vlan vlan-id
Specify a VLAN in the range of 1 to 4094.
Modification
This command was introduced.
single-host (default) mode only
auto mode for authorization
If the EAP success message is not sent, the user tries to authenticate every 60 seconds (the default)
by sending an EAP-start message.
Some hosts (for example, devices running Windows XP) cannot implement DHCP until they receive
an EAP success message.
Catalyst 3550 Multilayer Switch Command Reference
dot1x auth-fail vlan
2-81