Monitoring Protected Ports; Where To Go Next; Information About Port Blocking; Port Blocking - Cisco Catalyst 2960-XR Security Configuration Manual

Configuring Port-Based Traffic Control

Monitoring Protected Ports

Table 31: Commands for Displaying Protected Port Settings
Command
show interfaces [interface-id] switchport

Where to Go Next

•

Information About Port Blocking

Port Blocking

By default, the switch floods packets with unknown destination MAC addresses out of all ports. If unknown
unicast and multicast traffic is forwarded to a protected port, there could be security issues. To prevent unknown
unicast or multicast traffic from being forwarded from one port to another, you can block a port (protected or
nonprotected) from flooding unknown unicast or multicast packets to other ports.
With multicast traffic, the port blocking feature blocks only pure Layer 2 packets. Multicast packets that
Note
contain IPv4 or IPv6 information in the header are not blocked.

How to Configure Port Blocking

Blocking Flooded Traffic on an Interface

Before You Begin
The interface can be a physical interface or an EtherChannel group. When you block multicast or unicast
traffic for a port channel, it is blocked on all ports in the port-channel group.
OL-29434-01
Purpose
Displays the administrative and operational status of all
switching (nonrouting) ports or the specified port, including
port blocking and port protection settings.
Catalyst 2960-XR Switch Security Configuration Guide, Cisco IOS Release 15.0(2)EX1
Monitoring Protected Ports
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