ifconfig eth1 inet 192.168.10.20 netmask 255.255.255.0

ip route add 192.168.10.0/24 dev eth1

ifconfig en0 inet 192.168.1.100 netmask 255.255.255.0
ifconfig en6 inet 192.168.10.10 netmask 255.255.255.0

sysctl -w net.inet.ip.forwarding=1
sysctl -w net.inet.ip.fw.enable=1
route -n change -net 192.168.10.0/24 -interface en6