Internet Group Management Protocol (IGMP) is a protocol used to manage host membership in Internet Protocol version 4 (IPv4) multicast groups on a network segment. An IPv4 multicast group is a set of hosts that listen for IP traffic destined for a specified IP multicast address. IP multicast traffic is sent to a single MAC address but processed by multiple IP hosts. A host listens on a specified IP multicast address and receives all packets to that IP address.

The information that appears under IGMP in the RRAS MMC snap-in is the list of interfaces that are currently listening for IGMP messages from hosts on the attached subnet.

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