I had a long fight for this but this how I managed to find a workaround the issue in Ubuntu 18 using network-manager and GUI:
Download GUI packagesDownload GUI packages
$ sudo apt-get install network-manager-openvpn network-manager-openvpn-gnome
Network manager change [ifupdown] managed=true
$ sudo nano /etc/NetworkManager/NetworkManager.conf
.
.
[ifupdown]
managed=true
.
.
Import config.ovpnconfig.ovpn from GUI
(Settings -> Network -> VPN -> +)
Check imported connection id from from the connection file that was created automatically. (The file should be named config and id should also be config but they can be something else)
$ sudo grep /etc/NetworkManager/system-connections/config | grep "^id"
Change rendered to NetworkManager and add the new connection id inside the ethernets
$ sudo nano /etc/netplan/01-netcfg.yaml
network:
version: 2
renderedrenderer: NetworkManager
ethernets:
enp0s25:
dhcp4: yes
config:
dhcp4: yes
Apply changesApply changes
$ sudo netplan apply
Restart network-managerRestart network-manager
$ sudo service network-manager restart
Open the connection either from the GUI or using nmcli
$ nmcli connection up config