# The primary network interface
allow-hotplug eth0
iface eth0 inet dhcp
        post-up echo 2 > /proc/sys/net/ipv4/conf/eth0/force_igmp_version
        post-up echo 0 > /proc/sys/net/ipv4/conf/all/rp_filter
        post-up echo 0 > /proc/sys/net/ipv4/conf/eth0/rp_filter