Some theory
http://ntrg.cs.tcd.ie/undergrad/4ba2/multicast/antony/example.html
Praxis
Make sure that Multicast is enabled in kernel. May need recompiled.
ifconfig, check if interface has “MULTICAST”.
ip route add 224.0.0.0/4 dev wlan0.
disable icmp
echo
ignore
broadcasts: echo 0 > /proc/sys/net/ipv4/icmp
echo
ignore
broadcasts.