Cisco 2950 Software Configuration Guide - Page 459

Chapter 22 Configuring Port-Based Traffic Control Configuring Port Security Configuring Port Security You can use the port security feature to restrict input to an interface by limiting and identifying MAC addresses of the stations allowed to access the port. When you assign secure MAC addresses to a secure port, the port does not forward packets with source addresses outside the group of defined addresses. This section includes information about these topics: • Understanding Port Security, page 22-7 • Default Port Security Configuration, page 22-9 • Port Security Configuration Guidelines, page 22-9 • Enabling and Configuring Port Security, page 22-10 • Enabling and Configuring Port Security Aging, page 22-12 Understanding Port Security This section includes information about: • Secure MAC Addresses, page 22-7 • Security Violations, page 22-8 Secure MAC Addresses You can configure these types of secure MAC addresses: • Static secure MAC addresses-These are manually configured by using the 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 learned, 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, the interface does not need to dynamically relearn them when the switch restarts. Although sticky secure addresses can be manually configured, we do not recommend it. 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. 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 configuration, 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. A secure port can have from 1 to 132 associated secure addresses. The total number of available secure addresses on the switch is 1024. 78-11380-10 Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide 22-7