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Catalyst 3750 SwitchSoftware Configuration Guide
OL-8550-09
Chapter25 Configuring Port-Based Traffic Control
Configuring Port Security
To return the interface to the default condition where no traffic is blocked and normal forwarding occurs
on the port, use the no switchport block {multicast | unicast} interface configuration commands.
This example shows how to block unicast and Layer 2 multicast flooding on a port:
Switch# configure terminal
Switch(config)# interface gigabitethernet1/0/1
Switch(config-if)# switchport block multicast
Switch(config-if)# switchport block unicast
Switch(config-if)# end
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 contain this conceptual and configuration information:
•Understanding Port Security, page25-10
•Default Port Security Configuration, page25-12
•Port Security Configuration Guidelines, page25-12
•Enabling and Configuring Port Security, page25-13
•Enabling and Configuring Port Security Aging, page25-18
•Port Security and Switch Stacks, page 25-19
•Port Security and Private VLANs, page25-19