Bridge setup on Ubuntu 16.04

main.sh

# Remove all exist connections
# http://www.rene-pickhardt.de/cleaning-up-my-network-connections-on-ubuntu-linux-using-the-network-manager-nmcli/
for i in `nmcli c | \
  grep -o --  "[0-9a-fA-F]\{8\}-[0-9a-fA-F]\{4\}-[0-9a-fA-F]\{4\}-[0-9a-fA-F]\{4\}-[0-9a-fA-F]\{12\}"` ; \
  do nmcli connection delete uuid $i ; \
done

# "main" is name of bridge
nmcli con add type bridge ifname main
# "enp0s25" is name of your real interface
nmcli con add type bridge-slave ifname enp0s25 master bridge-main