Check IGMP Version on an Interface

May 2020

This is from CentOS 7.7. It may work with other Linux distros, but I cannot guarantee that.
One way to check the IGMP version being used by an interface is to use the following command:

cat /proc/net/igmp

Below is a sample output:

Idx Device : Count Querier Group Users Timer Reporter
1 lo : 1 V3
010000E0 1 0:00000000 0
2 eth0 : 4 V2
61FBDBED 1 0:00000000 1
FE7F02EB 3 0:00000000 1
120000E0 1 0:00000000 1
010000E0 1 0:00000000 0
3 eth1 : 3 V3
026400EF 1 0:00000000 0
016400EF 1 0:00000000 0
010000E0 1 0:00000000 0
4 eth2 : 2 V3
FE7F02EB 1 0:00000000 0
010000E0 1 0:00000000 0

Here we can see that eth0 is using IGMP V2, while eth1 and eth2 are using IGMP V3.