Configuring The Host Mode - Cisco Catalyst 3550 series Software Configuration Manual

Chapter 9 Configuring 802.1X Port-Based Authentication

Configuring the Host Mode

You can configure an 802.1X port for single-host or for multiple-hosts mode. In single-host mode, only
one host is allowed on an 802.1X port. When the host is authenticated, the port is placed in the authorized
state. When the host leaves the port, the port becomes unauthorized. Packets from hosts other than the
authenticated one are dropped.
You can attach multiple hosts to a single 802.1X-enabled port as shown in
this mode, only one of the attached hosts must be successfully authorized for all hosts to be granted
network access. If the port becomes unauthorized (re-authentication fails or an EAPOL-logoff message
is received), all attached clients are denied access to the network.
With the multiple-hosts mode enabled, you can use 802.1X to authenticate the port and port security to
manage network access for all MAC addresses, including that of the client.
Beginning in privileged EXEC mode, follow these steps to allow multiple hosts (clients) on an
802.1X-authorized port that has the dot1x port-control interface configuration command set to auto.
This procedure is optional.
Command
Step 1
configure terminal
Step 2
interface interface-id
Step 3
dot1x host-mode multi-host
Step 4 end
Step 5 show dot1x interface interface-id
Step 6
copy running-config startup-config
To disable multiple hosts on the port, use the no dot1x host-mode multi-host interface configuration
command.
This example shows how to enable Fast Ethernet interface 0/1 to allow multiple hosts:
Switch(config)# interface fastethernet0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# dot1x host-mode multi-host
Configuring a Guest VLAN
When you configure a guest VLAN, clients that are not 802.1X-capable are put into the guest VLAN
when the server does not receive a response to its EAPOL request/identity frame. Clients that are
802.1X-capable but fail authentication are not granted access to the network. The switch supports guest
VLANs in single-host or multiple-hosts mode.
Beginning in privileged EXEC mode, follow these steps to configure a guest VLAN. This procedure is
optional.
78-11194-09
Purpose
Enter global configuration mode.
Enter interface configuration mode, and specify the interface to which
multiple hosts are indirectly attached.
Allow multiple hosts (clients) on an 802.1X-authorized port.
Make sure that the dot1x port-control interface configuration command
set is set to auto for the specified interface.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Catalyst 3550 Multilayer Switch Software Configuration Guide
Configuring 802.1X Authentication
Figure 9-3 on page 9-5. In
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