IGMP snooping source IP address for messages

IGMP snooping is a Layer 2 feature used for multicast traffic, and has a scope of operation that is confined within a specific broadcast domain/VLAN. One of the prerequisites for IGMP snooping to operate in a specific VLAN is that the VLAN interface is assigned an IP address. It is this IP address that is used as the source of all IGMP messages.

This address is used as the query source address for the specific VLAN. The query source address for each VLAN on a switch can be determined using the following command:

SW1#show ip igmp snooping querier Vlan IP Address IGMP Version Port ------------------------------------------------------------- 1 v2 Gi0/1

The result will show you the source IP address for IGMP snooping messages for each individual VLAN.