Configure client your_client.ovpn
file,
# redirect all default traffic via the VPN
redirect-gateway def1
# redirect another network to NOT go via the VPN
route 10.0.0.0 255.255.255.0 net_gateway
route 192.168.0.0 255.255.255.0 net_gateway
# redirect the Intranet network 192.168.254/24 via the VPN
route 192.168.254.0 255.255.255.0
# redirect a host using a domainname to NOT go via the VPN
#route www.google.ca 255.255.255.255 net_gateway
Start OpenVPN client as service on Ubuntu,
# move `your_client.ovpn` to `/etc/openvpn/` and rename it to end in `your_client.conf`
sudo mv ~/Downloads/your_client.ovpn /etc/openvpn/your_client.conf
# reload service
sudo systemctl restart openvpn
# disable auto start
sudo systemctl disable openvpn
# enable auto start
sudo systemctl enable openvpn