Internet Group Management Protocol (IGMP) is a communication protocol used by hosts and adjacent routers on IP networks to establish multicast group memberships. IGMP can be used for online streaming video and gaming, and can allow more efficient use of resources when supporting these types of applications.
IGMP Proxy enables hosts that are not directly connected to a downstream router to join a multicast group sourced from an upstream network. IGMP Snooping constrains IPv4 multicast traffic at Layer 2 by configuring Layer 2 LAN ports dynamically to forward IPv4 multicast traffic only to those ports that want to receive it. IGMP Snooping runs on IGMP Version 3 that is backward compatible with the previous versions.
Note By default, multicast traffic from Any zone to Any zone is blocked by the firewall. When you enable IGMP Proxy and want to receive multicast packets from WAN to LAN, you must first uncheck Block Multicast Packets in the Firewall > Attack Protection page, and then create a firewall rule to permit multicast traffic from WAN to LAN. For information on configuring firewall rules to allow or deny multicast traffic, see Configuring a Firewall Rule to Allow Multicast Traffic, page 193.
2. Enter the following information:
• IGMP Proxy: Click On to enable IGMP Proxy so that the security appliance can act as a proxy for all IGMP requests and communicate with the IGMP servers of the ISP, or click Off to disable it.
• IGMP Version: Choose either IGMP Version 1 and 2 or IGMP Version 3.
– IGMP Version 1: Hosts can join multicast groups. There are no leave messages. Routers use a time-out based mechanism to discover the groups that are of no interest to the members.
– IGMP Version 2: Leave messages are added to the protocol. This allows group membership termination to be quickly reported to the routing protocol, which is important for high-bandwidth multicast groups and/or subnets with highly volatile group membership.
– IGMP Version 3: Major revision of the protocol. It allows hosts to specify the lists of hosts from which they want to receive traffic. Traffic from other hosts is blocked inside the network. It also allows hosts to block packets inside the network that come from sources sending unwanted traffic.
• IGMP Snooping: Snooping streamlines multicast traffic handling for VLANs. By examining (snooping) IGMP membership report messages from interested hosts, multicast traffic is limited to the subset of VLAN interfaces on which the hosts reside. IGMP snooping can reduce bandwidth consumption to avoid flooding the entire VLAN. Click On to enable IGMP snooping, or click Off to disable it.