In ubuntu, which process is sending igmp packets?

My Ubuntu keeps sending out IGMP Query requests for following IPs: 239.255.255.255.253, 224.1.1.7 and 234.55.66.77. I figured this out from Wireshark. As per IGMP spec, I believe query requests are sent only by routers. So,

1. Why is my machine sending these packets (i.e. behaving like a router)?
2. Which process sends these packets? I checked there is no mrouted or XORP or Quagga installed.

I would suggest you monitor the netstat to find out the 'culprit':

watch 'netstat -natp | grep 234.55.66.77'

There are some things you can check:

1. IGMP snooping feature is enabled:

   cat /sys/class/net/br0/bridge/multicast_snooping
   

2. you're using corosync in multicast mode