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Configuring IGMP (NSM Procedure)


On security devices, you must explicitly enable IGMP in Router mode on the interfaces that are connected to hosts. Security devices support the following Internet Group Management Protocol (IGMP) versions:

  • IGMPv1, as defined in RFC 1112, Host Extensions for IP Multicasting, defines the basic operations for multicast group memberships.

  • IGMPv2, as defined in RFC 2236, Internet Group Management Protocol, Version 2, expands on the functionality of IGMPv1.

  • IGMPv3, as defined in RFC 3376, Internet Group Management Protocol, Version 3, adds support for source filtering. Hosts running IGMPv3 indicate which multicast groups they want to join and the sources from which they expect to receive multicast traffic. IGMPv3 is required when you run Protocol Independent Multicast in source-specific multicast (PIM-SSM) mode.

To enable IGMP in Router mode:

  1. In the NSM navigation tree, select Device Manager > Devices. Double-click the device object to open the device configuration.
  2. In the device navigation tree, select Network > Interface.
  3. Double-click the interface on which you are enabling IGMP. The General Properties screen appears.
  4. In the interface navigation tree, select Protocol.
  5. Select the IGMP tab and configure the following options:
    • In the Type box, select Router.

    • Select Enable.

    • Click OK to save your changes to the interface.

  6. Click OK to save your changes to the device.

You can optionally change the default parameters for each interface on which IGMP is enabled. You can also use access lists to control traffic to and from an IGMP interface. First, create access lists that identify the following items:

  • Multicast groups that the hosts on a specified interface can join

  • Hosts from which an IGMP router interface can receive IGMP messages

  • Routers that are eligible for querier selection

Then, enter the access list IDs in the IGMP configuration screen of the IGMP interface(s). The security device then filters IGMP traffic based on the access lists.