Enabling IGMP

The Internet Group Management Protocol (IGMP) manages multicast groups by establishing, maintaining, and removing groups on a subnet. Multicast routing devices use IGMP to learn which groups have members on each of their attached physical networks. IGMP must be enabled for the router to receive IPv4 multicast packets. IGMP is only needed for IPv4 networks, because multicast is handled differently in IPv6 networks. IGMP is automatically enabled on all IPv4 interfaces on which you configure PIM and all IPv4 broadcast interfaces when you configure DVMRP.

If IGMP is not running on an interface—either because neither PIM nor DVMRP is configured on the interface or because IGMP is explicitly disabled on the interface—you can explicitly enable IGMP.

To explicitly enable IGMP:

If neither PIM nor DVMRP is running on the interface, explicitly enabling IGMP by including the interface name.
[edit]user@host# edit protocols igmpuser@host# set interface fe-0/0/0.0
Check to see if IGMP is disabled on any interfaces. In the following example, IGMP is disabled on a Gigabit Ethernet interface.
[edit protocols igmp]user@host# show
```
interface fe-0/0/0.0;
interface ge-0/0/0.0 {
    disable;
}
```
Enable IGMP on the interface by deleting the disable statement.
[edit protocols igmp]delete interface ge-0/0/0.0 disable
Verify the configuration.
[edit protocols igmp]user@host# show
```
interface fe-0/0/0.0;
interface ge-0/0/0.0;
```
Verify the operation of IGMP on the interfaces by checking the output of the show igmp interface command.

Enabling IGMP

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