Changing IGMP version on Ubuntu

Sometimes users of IP Multicast based probes for IPTV on Ubuntu Linux ask how to use IGMPv2 instead of IGMPv3 (which is currently default with Ubuntu lynx Linux).  IGMP behaviour is defined by the Linux kernel instead and supported from linux kernel 2.6.

djstava@Thinkpad:~$ su -
Password:
root@Thinkpad:~# cd /
root@Thinkpad:/#

root@Thinkpad:/# cat /proc/sys/net/ipv4/conf/eth0/force_igmp_version
0


This display the highest available version.

root@Thinkpad:/# echo "2" > /proc/sys/net/ipv4/conf/eth0/force_igmp_version
root@Thinkpad:/# cat /proc/sys/net/ipv4/conf/eth0/force_igmp_version
2


The first statement change the IGMP version from 3 to 2.

Check by the command

tcpdump -i eth0 igmp

djstava