etcnetworkinterfaces

/etc/network/interfaces:
# interfaces(5) file used by ifup(8) and ifdown(8)

# Please note that this file is written to be used with dhcpcd
# For static IP, consult /etc/dhcpcd.conf and 'man dhcpcd.conf'

# Include files from /etc/network/interfaces.d:
# /etc/network/interfaces.d is an empty directory
source-directory /etc/network/interfaces.d