VPN tunnel from DO to private network
I'm running a local network, with a few web servers and what not. For some of my web servers, I use a DO server as a reverse proxy and cache.
As of right now it is just connecting through the public IPs, but I wish to create a private VPN (or sock) tunnel between the DO server and my private network. I've searched this DO site and google, but they mostly come up with a normal VPN client which is not what I need. The VPN doesn't need to forward any traffic, just simply provide a private (secure) network between the two networks.
The server which i use on DO is Ubuntu 16.04, and the load balancer on my private network is a raspberry pi running Raspbian.
Anyone able to help me out? or at least point me the right way?