25-7
Cisco Catalyst Blade Switch 3130 for Dell Software Configuration Guide
OL-13270-01
Chapter25 Configuring Port-Based Tra ffic Control Configuring Port Security

Default Port Blocking Configuration

The default is to not block flooding of unknown multicast and unicast traffic out of a port, but to flood
these packets to all ports.

Blocking Flooded Traffic on an Interface

Note The interface can be a physical interface or an EtherChannel group. When you block multicas t or unicast
traffic for a port channel, it is blocked on all ports in the port-channel group.
Beginning in privileged EXEC mode, follow these steps to disable the flooding of mult icast and unicast
packets out of an interface:
To return the interface to the default condition where no traffic is blocke d and normal forwa rding occurs
on the port, use the no switchport block {multicast | unicast} interface configuration commands.
This example shows how to block unicast and 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 add resses. If
you limit the number of secure MAC addresses to one and assign a singl e se cu re M AC address, th e
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 flagg ed.
Command Purpose
Step1 configure terminal Enter global configuration mode.
Step2 interface interface-id Specify the interface to be configured, and enter interface
configuration mode.
Step3 switchport block multicast Block unknown multicast forwarding out of the port.
Step4 switchport block unicast Block unknown unicast forwarding out of the port.
Step5 end Return to privileged EXEC mode.
Step6 show interfaces interface-id switchport Verify your entries.
Step7 copy running-config startup-config (Optional) Save your entries in the configuration file.