Hi @davidSenseIT,
Yes, there is a good way to do it. You’ll need to set up the VPN and then block all access to your interface except your VPN’s IP address. Firstly, you’ll need to configure your VPN, I’ll recommend using OpenVPN. DigitalOcean has a pretty good tutorial on how to actually configure it and use it afterward:
https://www.digitalocean.com/community/tutorials/how-to-set-up-an-openvpn-server-on-ubuntu-18-04
OpenVPN is a full-featured, open-source Secure Socket Layer (SSL) VPN solution that accommodates a wide range of configurations. In this tutorial, you will set up an OpenVPN server on an Ubuntu 18.04 server and then configure access to it from Windows, macOS, iOS and/or Android. This tutorial will keep the installation and configuration steps as simple as possible for each of these setups.
Once you’ve done it, then you can go ahead and disable the access for your application, except of course the IP of your newly configured VPN.
Regards,
KDSys

by Mark Drake
OpenVPN is a full-featured, open-source Secure Socket Layer (SSL) VPN solution that accommodates a wide range of configurations. In this tutorial, you will set up an OpenVPN server on an Ubuntu 18.04 server and then configure access to it from Windows, OS X, iOS and/or Android devices. This tutorial will keep the installation and configuration steps as simple as possible for each of these setups.