Port sharing with an HTTPS server
A common OpenVPN setup to allow road warriors to reach the home office is to have OpenVPN listen on the secure web server (HTTPS) port  443
. The downside is that you can no longer use that port on the OpenVPN server to actually host a secure website. OpenVPN 2.1 introduces a new port-sharing
directive, enabling dual use of a TCP port. All traffic that is detected as OpenVPN traffic is processed by the OpenVPN server itself, and all other traffic is forwarded to another (local) machine and/or port.
In this recipe, we will set up an OpenVPN server to share TCP port 443
with a web server and we will show that both OpenVPN and a web browser can successfully connect to this server.
Getting ready
We will use the following network layout:
Set up the client and server certificates using the first recipe from Chapter 2, Client-server IP-only Networks. For this recipe, the server computer was running CentOS 6 Linux and OpenVPN 2.3.12. The client was running...