Install gadmin-openvpn-server by entering the following commands in the terminal:
sudo apt update sudo apt install gadmin-openvpn-server
Description:
GTK+ configuration tool for openvpn (server)
gadmin-openvpn-server is a fast and easy to use GTK+ administration tool for the OpenVPN server.
Homepage: http://www.gadmintools.org/
Version: 0.1.5-3.1build1
Section: universe/admin