configure kernel
edit /etc/sysctl.conf:
net.ipv4.conf.all.mc_forwarding = 1
net.ipv4.conf.default.mc_forwarding = 1
net.ipv4.conf.lo.mc_forwarding = 1
net.ipv4.conf.eth0.mc_forwarding = 1
net.ipv4.conf.wlan0.mc_forwarding = 1
net.inet.ip.mforwarding=1
multicast_router=YES