Summary
After spending years in the OpenVPN IRC channel and on the OpenVPN support forum, there are some recurring difficulties among the server administration user base: basic networking and routing, X.509 certificate management, and user or client authentication. Having now read this book, you should have a solid grasp of these concepts and understand the underlying mechanisms. The differences between the tun and tap virtual network adapters have been discussed as well.
OpenVPN is a very active open source project and is ever evolving. The techniques and examples within Mastering OpenVPN will likely not go stale in the near future. Inefficiencies within the code are anticipated, however, so we strongly recommend that you read the manual (man page) available at https://openvpn.net/index.php/open-source/documentation/manuals.html.
Like most open source projects, OpenVPN needs more help—more volunteers to help moderate the forum and help on IRC, and additional developers to help increase...