Enable bridge
sudo ifconfig bridge0 create
sudo ifconfig bridge0 up
sudo ifconfig bridge0 addm en6 addm en3
sudo sysctl -w net.inet.ip.forwarding=1
Disable bridge
sudo ifconfig bridge0 down
sudo ifconfig bridge0 deletem en6 deletem en3
sudo ifconfig bridge0 destroy
sudo sysctl -w net.inet.ip.forwarding=0