Cisco Catalyst 2960 Series, Configuration Manual

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• When configuring the inaccessible authentication bypass feature, follow these guidelines:
◦ The feature is supported on 802.1x port in single-host mode and multihosts mode.
◦ If the client is running Windows XP and the port to which the client is connected is in the
critical-authentication state, Windows XP might report that the interface is not authenticated.
◦ If the Windows XP client is configured for DHCP and has an IP address from the DHCP server,
receiving an EAP-Success message on a critical port might not re-initiate the DHCP configuration
process.
◦ You can configure the inaccessible authentication bypass feature and the restricted VLAN on an
802.1x port. If the switch tries to re-authenticate a critical port in a restricted VLAN and all the
RADIUS servers are unavailable, switch changes the port state to the critical authentication state
and remains in the restricted VLAN.
• You can configure any VLAN except an RSPAN VLAN or a voice VLAN as an 802.1x restricted VLAN.
The restricted VLAN feature is not supported on internal VLANs (routed ports) or trunk ports; it is
supported only on access ports.
MAC Authentication Bypass
These are the MAC authentication bypass configuration guidelines:
• Unless otherwise stated, the MAC authentication bypass guidelines are the same as the 802.1x
authentication guidelines.
• If you disable MAC authentication bypass from a port after the port has been authorized with its MAC
address, the port state is not affected.
• If the port is in the unauthorized state and the client MAC address is not the authentication-server
database, the port remains in the unauthorized state. However, if the client MAC address is added to the
database, the switch can use MAC authentication bypass to re-authorize the port.
• If the port is in the authorized state, the port remains in this state until re-authorization occurs.
• You can configure a timeout period for hosts that are connected by MAC authentication bypass but are
inactive. The range is 1to 65535 seconds.
Maximum Number of Allowed Devices Per Port
This is the maximum number of devices allowed on an 802.1x-enabled port:
• In single-host mode, only one device is allowed on the access VLAN. If the port is also configured with
a voice VLAN, an unlimited number of Cisco IP phones can send and receive traffic through the voice
VLAN.
• In multidomain authentication (MDA) mode, one device is allowed for the access VLAN, and one IP
phone is allowed for the voice VLAN.
• In multihost mode, only one 802.1x supplicant is allowed on the port, but an unlimited number of
non-802.1x hosts are allowed on the access VLAN. An unlimited number of devices are allowed on the
voice VLAN.
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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How to Configure 802.1x Port-Based Authentication