Cisco Catalyst 3550 series Software Configuration Manual page 814

Configuring IP Multicast Routing
Defining the IP Multicast Boundary
You define a multicast boundary to prevent Auto-RP messages from entering the PIM domain. You
create an access list to deny packets destined for 224.0.1.39 and 224.0.1.40, which carry Auto-RP
information.
Beginning in privileged EXEC mode, follow these steps to define a multicast boundary:
Command
Step 1
configure terminal
Step 2 access-list access-list-number deny
source [source-wildcard]
Step 3 interface interface-id
Step 4
ip multicast boundary
access-list-number
Step 5
end
Step 6
show running-config
Step 7 copy running-config startup-config
To remove the boundary, use the no ip multicast boundary interface configuration command.
This example shows a portion of an IP multicast boundary configuration that denies Auto-RP
information:
Switch(config)# access-list 1 deny 224.0.1.39
Switch(config)# access-list 1 deny 224.0.1.40
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# ip multicast boundary 1
Catalyst 3550 Multilayer Switch Software Configuration Guide
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Purpose
Enter global configuration mode.
Create a standard access list, repeating the command as many times as
necessary.
For access-list-number, the range is 1 to 99.
•
The deny keyword denies access if the conditions are matched.
•
For source, enter multicast addresses 224.0.1.39 and 224.0.1.40,
•
which carry Auto-RP information.
(Optional) For source-wildcard, enter the wildcard bits in dotted
•
decimal notation to be applied to the source. Place ones in the bit
positions that you want to ignore.
Recall that the access list is always terminated by an implicit deny
statement for everything.
Enter interface configuration mode, and specify the interface to be
configured.
Configure the boundary, specifying the access list you created in Step 2.
Return to privileged EXEC mode.
Verify your entries.
(Optional) Save your entries in the configuration file.
Chapter 34 Configuring IP Multicast Routing
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