Cisco Cisco IOS Software Release 12.2(33)SRE

IGMP Version 3 accommodates extended access lists, which allow you to leverage an important 
advantage of Source Specific Multicast (SSM) in IPv4, that of basing access on source IP address. Prior 
to this feature, an IGMP access list accepted only a standard access list, allowing membership reports to 
be filtered based only on multicast group addresses.

IGMPv3 allows multicast receivers not only to join to groups, but to groups including or excluding 
sources. For appropriate access control, it is therefore necessary to allow filtering of IGMPv3 messages 
not only by group addresses reported, but by group and source addresses. IGMP extended access lists 
introduce this functionality. Using SSM with an IGMP extended access list (ACL) allows you to permit 
or deny source S and group G (S, G) in IGMPv3 reports, thereby filtering IGMPv3 reports based on 
source address, group address, or both. 

Configuration information is included in the “Customizing IGMP” chapter in the 

, Release 12.4T, at the following URL:

Command reference information is included in the 

, 

Release 12.2SR, at the following URL:

The following command is modified for this feature:

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and 
figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and 
coincidental.

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