Cisco 2950G 24 Software Configuration Guide - Page 418

Configuring Port Security Chapter 18 Configuring Port-Based Traffic Control Beginning in privileged EXEC mode, follow these steps to define a port as a protected port: Step 1 Step 2 Command configure terminal interface interface-id Step 3 Step 4 Step 5 Step 6 switchport protected end show interfaces interface-id switchport copy running-config startup-config Purpose Enter global configuration mode. Specify the type and number of the physical interface to configure, for example gigabitethernet0/1, and enter interface configuration mode. Configure the interface to be a protected port. Return to privileged EXEC mode. Verify your entries. (Optional) Save your entries in the configuration file. To disable protected port, use the no switchport protected interface configuration command. This example shows how to configure Gigabit Ethernet interface 0/1 as a protected port and verify the configuration: Switch# configure terminal Switch(config)# interface gigabitethernet0/1 Switch(config-if)# switchport protected Switch(config-if)# end Switch# show interfaces gigabitethernet0/1 switchport Name: Gi0/1 Switchport: Enabled Protected: True Unknown unicast blocked: disabled Unknown multicast blocked: disabled 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. If you limit the number of secure MAC addresses to one and assign a single secure MAC address, the workstation attached to that port is assured the full bandwidth of the port. If a port is configured as a secure port and the maximum number of secure MAC addresses is reached, when the MAC address of a station attempting to access the port is different from any of the identified secure MAC addresses, a security violation occurs. Also, if a station with a secure MAC address configured or learned on one secure port attempts to access another secure port, a violation is flagged. These sections include port security configuration information and procedures: • Understanding Port Security, page 18-5 • Default Port Security Configuration, page 18-7 • Port Security Configuration Guidelines, page 18-7 • Enabling and Configuring Port Security, page 18-7 • Enabling and Configuring Port Security Aging, page 18-10 18-4 Catalyst 2950 Desktop Switch Software Configuration Guide 78-14982-01