Hello Muhammad
Remember that IGMP snooping is a Layer 2 feature, 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. This can be seen on page two of the following Cisco Documentation as a prerequisite for IGMP snooping:
It is this IP address that is used as the source address for IGMP. Specifically, it says:
Configure an IP address on the VLAN interface. When enabled, the IGMP snooping querier uses the IP address as the query source address.
To determine the current querier IP address, use the following command:
SW1#show ip igmp snooping querier
Vlan IP Address IGMP Version Port
-------------------------------------------------------------
1 192.168.1.254 v2 Gi0/1
The result will show you the source IP address for IGMP snooping messages for each individual VLAN.
I hope this has been helpful!
Laz