$IPTABLES -I zone_${zone}_nat 1 -t nat -o "$ifname" -j MASQUERADE
$IPTABLES -I PREROUTING 1 -t nat -i "$ifname" -j zone_${zone}_prerouting
$IPTABLES -A forward -i "$ifname" -j zone_${zone}_forward
$IPTABLES -I zone_${zone}_nat 1 -t nat -o "$ifname" -j MASQUERADE
$IPTABLES -I PREROUTING 1 -t nat -i "$ifname" -j zone_${zone}_prerouting
$IPTABLES -A forward -i "$ifname" -j zone_${zone}_forward