Cisco Catalyst 4500 series Administration Manual page 1207

Chapter 46 Configuring 802.1X Port-Based Authentication
Unidirectional controlled port only works when Spanning Tree PortFast is enabled on the port.
Note
Unidirectional controlled port and Spanning Tree PortFast should be configured on a switch port that
connects to a host. If two such ports are connected together with an Ethernet cable, high CPU utilization
may result because host learning will be flapping between the two ports.
This example shows how to enable unidirectional port control:
Cisco IOS Release 12.2(50)SG and later
Switch# configure terminal
Switch(config)# interface gigabitethernet3/3
Switch(config-if)# switchport mode access
Switch(config-if)# dot1x pae authenticator
Switch(config-if)# authentication port-control auto
Switch(config-if)# authentication control-direction in
Switch(config-if)# end
Switch# show dot1x int g3/3
Dot1x Info for GigabitEthernet3/3
-----------------------------------
PAE
PortControl
ControlDirection
HostMode
ReAuthentication
QuietPeriod
ServerTimeout
SuppTimeout
ReAuthPeriod
ReAuthMax
MaxReq
TxPeriod
RateLimitPeriod
Switch#
Cisco IOS Release 12.2(46)SG or earlier
Switch# configure terminal
Switch(config)# interface gigabitethernet3/3
Switch(config-if)# switchport mode access
Switch(config-if)# dot1x pae authenticator
Switch(config-if)# authentication port-control auto
Switch(config-if)# dot1x control-direction in
Switch(config-if)# end
Switch# show dot1x int g3/3
Dot1x Info for GigabitEthernet3/3
-----------------------------------
PAE
PortControl
ControlDirection
HostMode
ReAuthentication
QuietPeriod
ServerTimeout
SuppTimeout
ReAuthPeriod
ReAuthMax
MaxReq
TxPeriod
RateLimitPeriod
Switch#
OL_28731-01
= AUTHENTICATOR
= AUTO
= In
= SINGLE_HOST
= Disabled
= 60
= 30
= 30
= 3600 (Locally configured)
= 2
= 2
= 30
= 0
= AUTHENTICATOR
= AUTO
= In
= SINGLE_HOST
= Disabled
= 60
= 30
= 30
= 3600 (Locally configured)
= 2
= 2
= 30
= 0
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
Configuring 802.1X Port-Based Authentication
46-69