/etc/network/interfaces

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto ens32
iface ens32 inet static
    address 20.1.40.109
    netmask 255.255.255.0
    gateaway 20.1.40.1
    dns-nameservers 20.1.40.23 
    up route add -net 15.17.160.0 netmask 255.255.240.0 gw 20.1.40.1
    down route del -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.2.1

# The primary network interface
auto ens33
iface ens33 inet dhcp