port security

PORT SECURITY GUIDELINES

Configure port security

If I were to configure port security on Fast Ethernet port 0/1 I would type in the following commands:

ALSwitch(config)#interface fastethernet 0/1

ALSwitch(config-if)#switchport mode access

ALSwitch(config-if)#switchport port-security

ALSwitch(config-if)#switchport port-security mac-address sticky

ALSwitch(config-if)#switchport port-security maximum 1

ALSwitch(config-if)#switchport port-security violation shutdown

This configuration allows the port to learn the first MAC address it is connected to and “sticks it” to the port. In this configuration only one MAC address is learned. If any other MAC address is detected the port is configured to shutdown as set in the violation command above.

If you wanted to accept the new PC on that port and clear the alarm and enable the port, type in the following:

ALSwitch#clear port-security sticky

ALSwitch(config)#interface fa 0/1

ALSwitch(config-if)#shutdown

ALSwitch(config-if)#no shutdown

The “shutdown” “no shutdown” commands under the interface is how we “bounce” the interface (restart the interface).