The concept here is to forward VPN traffic received on the public interface of the Internet router (via incoming TCP port 1194) to the OpenVPN server's interface. The VPN server authenticates the connection, and regulates forwarding traffic to and from various destinations on your private network, based on a defined set of rules. This could include forwarding traffic to your desktop to enable a remote sharing via VNC, RDP, SSH, or other protocol.
In this post, I'd like to share my most recent home lab project - a nested OpenVPN server. I refer to it as nested, because it is running completely within my desktop computer. See the illustration below.
The idea for this project came along when I working on setting up a VPN with my older Linksys router. Basically, I wanted to come up with a way to run a home lab VPN server without requiring any additional hardware, and I wanted to incorporate virtualization into this project. In addition, running it as a VM allows for fairly safe and controlled experimentation, without running the risk of bricking one's router with non-standard firmware.
