homesrv ikar # sysctl net.ipv4.conf.eth0.rp_filter
net.ipv4.conf.eth0.rp_filter = 0

homesrv ikar # sysctl net.ipv4.conf.all.rp_filter
net.ipv4.conf.all.rp_filter = 0

# less /usr/src/linux/.config | grep \(MROUTE\|MULTICAST\)
CONFIG_IP_MULTICAST=y
CONFIG_IP_MROUTE=y
CONFIG_IP_MROUTE_MULTIPLE_TABLES=y

 # sysctl net.ipv4.conf.all.force_igmp_version
net.ipv4.conf.all.force_igmp_version = 0