root@basil-host:/etc/network# cat /etc/network/interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback
source /etc/network/interfaces.d/*.cfg
root@versa-analytics:/etc/network#
root@versa-analytics:/etc/network# cat /etc/network/interfaces.d/eth0.cfg
# The primary network interface
auto eth0
iface eth0 inet dhcp
iface eth0 inet6 auto
  privext 0
root@basil-host:/etc/network#