Persistent Static Routes in Ubuntu Linux

In Ubuntu Linux, in order to make Static Routes Persistent, we need to add route entries to the network interface file (/etc/network/interfaces) using up lines.

Example:
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# Generated by debian-installer.

# The loopback interface
auto lo
iface lo inet loopback
auto eno2
up ip route add 172.16.0.0/12 via 192.168.0.1
#up ip route add  172.30.0.0/16 via 192.168.0.1 dev eno2
#up ip route add  172.29.0.0/16 via 192.168.0.1 dev eno2

However, if your interfaces are being managed by Network Manager, then you can do the following:

nmcli device modify ${device_name} \

    ipv4.routes "${destination_network} ${gateway}" \

    ipv4.route-metric 25

For example:

$ sudo nmcli device modify eno2 ipv4.routes "172.16.0.0/12 192.168.0.1" ipv4.route-metric 25                                                                         Connection successfully reapplied to device 'eno2'.

$ sudo nmcli device modify eno1 ipv4.routes "172.16.0.0/12 192.168.0.1" ipv4.route-metric 25

Connection successfully reapplied to device 'eno1'.

$ sudo systemctl restart NetworkManager.service