Cisco Catalyst 4500 Series Command Reference Guide

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Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.4.0SG and IOS 15.1(2)SG)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
switchport block
switchport block
To prevent the unknown multicast or unicast packets from being forwarded, use the switchport block
interface configuration command. To allow the unknown multicast or unicast packets to be forwarded,
use the no form of this command.
switchport block {multicast | unicast}
no switchport block {multicast | unicast}
Syntax Description
Defaults Unknown multicast and unicast traffic are not blocked.
All traffic with unknown MAC addresses is sent to all ports.
Command Modes Interface configuration mode
Command History
Usage Guidelines You can block the unknown multicast or unicast traffic on the switch ports.
Blocking the unknown multicast or unicast traffic is not automatically enabled on the switch ports; you
must explicitly configure it.
Note For more information about blocking the packets, refer to the software configuration guide for this
release.
Examples This example shows how to block the unknown multicast traffic on an interface:
Switch(config-if)# switchport block multicast
You can verify your setting by entering the show interfaces interface-id switchport privileged EXEC
command.
Related Commands
multicast Specifies that the unknown multicast traffic should be blocked.
unicast Specifies that the unknown unicast traffic should be blocked.
Release Modification
12.1(19)EW Support for this command was introduced on the Catalyst 4500 series switch.
Command Description
show interfaces switchport Displays the administrative and operational status of a
switching (nonrouting) port.

Cisco Catalyst 4500 Series Specifications

General

Series	Catalyst 4500 Series
Category	Switch
Layer Support	Layer 2, Layer 3
Form Factor	Modular chassis
Stackable	No
Chassis Slots	3, 6, 7, 10
Power Supply Options	AC, DC
Redundancy	Power supply, Supervisor engine
Network Management	Cisco IOS Software CLI, SNMP, Cisco Prime Infrastructure
Features	Security, QoS
Port Density	Up to 384 ports per chassis
Security Features	802.1X, ACLs, DHCP Snooping, Dynamic ARP Inspection, IP Source Guard
Supervisor Engine	8-E