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Cisco IE 2000 Switch Software Configuration Guide
OL-25866-01
Chapter 13 Configuring IEEE 802.1x Port-Based Authentication
Information About Configuring IEEE 802.1x Port-Based Authentication
Restricted VLANs are supported only on 802.1x ports in single-host mode and on Layer 2 ports.
You can configure any active VLAN except an RSPAN VLAN, a primary private VLAN, or a voice
VLAN as an 802.1x restricted VLAN. The restricted VLAN feature is not supported on i nternal VLANs
(routed ports) or trunk ports; it is supported only on access ports.
Other security features such as dynamic ARP inspection, D HCP snooping, and IP source guard can be
configured independently on a restricted VLAN.
For more information, see the “Configuring a Restricted VLAN” section on page 13-43.
802.1x Authentication with Inaccessible Authentication Bypass
Use the inaccessible authentication bypass feature, also referred to as critical authentication or the AAA
fail policy, when the switch cannot reach the configured RADIUS servers and new hosts cannot be
authenticated. You can configure the switch to connect those hosts to critical ports.
When a new host tries to connect to the critical port, that host is moved to a user-specified access VLAN,
the critical VLAN. The administrator gives limited authentication to the hosts.
When the switch tries to authenticate a host connected to a critical port, the switch checks the status of
the configured RADIUS server. If a server is available, the switch can authenticate the host. However, if
all the RADIUS servers are unavailable, the switch grants network access to the host and puts the port
in the critical-authentication state, which is a special case of the authentication state.

Support on Multiple-Authentication Ports

When a port is configured on any host mode and the AAA server is unavailable, the port is then
configured to multi-host mode and moved to the critical VLAN. To support this inaccessible bypass on
multiple-authentication (multiauth) ports, use the authentication event server dead action reinitialize
vlan vlan-id command. When a new host tries to connect to the critical port, that port is reinitialized and
all the connected hosts are moved to the user-specified access VLAN.
This command is supported on all host modess.

Authentication Results

The behavior of the inaccessible authentication bypass feature depends on the authorization state of th e
port:
• If the port is unauthorized when a host connected to a critical port tries to authenticate and all servers
are unavailable, the switch puts the port in the critical-authentication state in the
RADIUS-configured or user-specified access VLAN.
• If the port is already authorized and reauthentication occurs, the switch puts the critical port in the
critical-authentication state in the current VLAN, which might be the one previously assigned by
the RADIUS server.
• If the RADIUS server becomes unavailable during an authentication exchange, the current exchange
times out, and the switch puts the critical port in the critical-authentication state during the next
authentication attempt.