Users Guide

1. Enter the following command in CONFIGURATION mode:
switchport port-security
NOTE: By default, port security is enabled globally. To disable the port security feature on the system, use the no
switchport port-security command in CONFIGURATION mode.
Enable port security on an interface
To enable port security on an interface:
1. Enter the following command in INTERFACE mode:
switchport port-security
2. Enable port security in CONFIGURATION-PORT-SECURITY mode:
no disable
NOTE: To disable the port security feature on an interface, use the disable command in CONFIGURATION-PORT-
SECURITY mode.
Configure the MAC address learning limit
After you enable port security on an interface, the interface can learn one secure MAC address by default. This limit is applicable
for both secure dynamic and secure static MAC addresses.
To configure the MAC address learning limit:
1. Enter the following command in INTERFACE mode:
switchport port-security
2. Configure the number of secure MAC addresses that an interface can learn in INTERFACE PORT SECURITY mode:
mac-learn {limit | no-limit}
For the limit keyword, the range is from 0 to 3072. To enable the interface to learn the maximum number of MAC
addresses that the hardware supports, use the no-limit keyword.
MAC address learning limit example
OS10# configure terminal
OS10(config)#interface ethernet 1/1/1
OS10(config-if-eth1/1/1)#switchport port-security
OS10(config-if-port-sec)# no disable
OS10(config-if-port-sec)#mac-learn limit 100
Configure MAC address learning limit violation actions
Use the following commands in INTERFACE PORT SECURITY mode:
● To display which MAC address causes a violation, use the log option. The system also drops the packet.
OS10(config-if-port-sec)#mac-learn limit violation log
● To drop the packet when a MAC address learning limit violation occurs, use the drop option.
OS10(config-if-port-sec)#mac-learn limit violation drop
● To forward the packet when a MAC address learning limit violation occurs, use the flood option. The system does not learn
the MAC address.
OS10(config-if-port-sec)#mac-learn limit violation forward
● To shut down an interface on a MAC address learning limit violation, use the shutdown option.
OS10(config-if-port-sec)#mac-learn limit violation shutdown
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Security