O'Reilly logo

Mastering OpenVPN by Jan Just Keijser, Eric F Crist

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

OpenVPN internals

The design of OpenVPN is not extensively documented, but most of the internals of OpenVPN can be discovered by looking at the source code.

The tun/tap driver

One of the basic building blocks of OpenVPN is the tun/tap driver. The concept of the tun/tap driver comes from the Unix/Linux world, where it is often natively available as part of the operating system. This is a virtual network adapter that is treated by the operating system as either a point-to-point adapter (tun-style) for IP-only traffic or as a full virtual Ethernet adapter for all types of traffic (tap-style). At the backend of this adapter is an application, such as OpenVPN, to process the incoming and outgoing traffic. Linux, Free/Open/NetBSD, Solaris and Mac OS include ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required