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Cisco Nexus 5500 Series NX-OS Layer 2 Interfaces Command Reference
OL-27880-02
Chapter S Commands
switchport block
switchport block
To prevent the unknown multicast or unicast packets from being forwarded, use the
switchport block
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
Command Default
Unknown multicast and unicast traffic are not blocked. All traffic with unknown MAC addresses is sent
to all ports.
Command Modes
Interface configuration mode
Virtual Ethernet 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.
Examples
This example shows how to block the unknown multicast traffic on an interface:
switch#
configure terminal
switch(config)#
interface ethernet 1/1
switch(config-if)#
switchport block multicast
switch(config-if)#
This example shows how to block the unknown unicast traffic on a virtual Ethernet interface:
switch#
configure terminal
switch(config)#
interface vethernet 1
switch(config-if)#
switchport block uniicast
switch(config-if)#
multicast
Specifies that the unknown multicast traffic should be blocked.
unicast
Specifies that the unknown unicast traffic should be blocked.
Release
Modification
5.2(1)N1(1)
This command was introduced.
