21-8
Catalyst 2960 Switch SoftwareConfiguration Guide
78-16881-01
Chapter21 Configuring Port-Based Traffic Control
Configuring Port Security
•Enabling and Configuring Port Security, page 21-11
•Enabling and Configuring Port Security Aging, page 21-15
Understanding Port Security
These sections contain this conceptual information:
•Secure MAC Addresses, page 21-8
•Security Violations, page 21-9

Secure MAC Addresses

You configure the maximum number of secure addresses allowed on a port by using the switchport
port-security maximum value interface configuration command.
Note If you try to set the maximum value to a number less than the number of secure addresses already
configured on an interface, the command is rejected.
The switch supports these types of secure MAC addresses:
•Static secure MAC addresses—These are manually configured by using th e switchport
port-security mac-address mac-address interface configuration command, stored in the address
table, and added to the switch running configuration.
•Dynamic secure MAC addresses—These are dynamically configured, stored only in the address
table, and removed when the switch restarts.
•Sticky secure MAC addresses—These can be dynamically learned or manually configured, stored in
the address table, and added to the running configuration. If these addresses are saved in the
configuration file, when the switch restarts, the interface does not need to dynamically reconfigure
them.
You can configure an interface to convert the dynamic MAC addresses to sticky secure MAC addresses
and to add them to the running configuration by enabling sticky learning. To enable sticky learning, enter
the switchport port-security mac-address sticky interface configuration command. When you enter
this command, the interface converts all the dynamic secure MAC addresses, including those that were
dynamically learned before sticky learning was enabled, to sticky secure MAC addresses. All sticky
secure MAC addresses are added to the running configuration.
The sticky secure MAC addresses do not automatically become part of the configuration file, which is
the startup configuration used each time the switch restarts. If you save the sticky secure MAC addresses
in the configuration file, when the switch restarts, the interface does not need to relearn these addresses.
If you do not save the sticky secure addresses, they are lost.
If sticky learning is disabled, the sticky secure MAC addresses are converted to dynamic secure
addresses and are removed from the running configuration.
The maximum number of secure MAC addresses that you can configure on a switch is set by the
maximum number of available MAC addresses allowed in the system. This number is the total of
available MAC addresses, including those used for other Layer 2 functions and any other secure MAC
addresses configured on interfaces.