Book Image

Mastering OpenVPN

By : Jan Just Keijser, Eric F Crist
Book Image

Mastering OpenVPN

By: Jan Just Keijser, Eric F Crist

Overview of this book

Security on the internet is increasingly vital to both businesses and individuals. Encrypting network traffic using Virtual Private Networks is one method to enhance security. The internet, corporate, and “free internet” networks grow more hostile every day. OpenVPN, the most widely used open source VPN package, allows you to create a secure network across these systems, keeping your private data secure. The main advantage of using OpenVPN is its portability, which allows it to be embedded into several systems. This book is an advanced guide that will help you build secure Virtual Private Networks using OpenVPN. You will begin your journey with an exploration of OpenVPN, while discussing its modes of operation, its clients, its secret keys, and their format types. You will explore PKI: its setting up and working, PAM authentication, and MTU troubleshooting. Next, client-server mode is discussed, the most commonly used deployment model, and you will learn about the two modes of operation using "tun" and "tap" devices. The book then progresses to more advanced concepts, such as deployment scenarios in tun devices which will include integration with back-end authentication, and securing your OpenVPN server using iptables, scripting, plugins, and using OpenVPN on mobile devices and networks. Finally, you will discover the strengths and weaknesses of the current OpenVPN implementation, understand the future directions of OpenVPN, and delve into the troubleshooting techniques for OpenVPN. By the end of the book, you will be able to build secure private networks across the internet and hostile networks with confidence.
Table of Contents (17 chapters)
Mastering OpenVPN
About the Authors
About the Reviewers

Troubleshooting routing issues

Most of the questions asked on the OpenVPN e-mail lists and user forums are actually routing questions. Setting up a VPN connection is one thing, but integrating it into your existing network is quite another. To a novice, the difficult part is to see where OpenVPN stops and where routing begins. This section is intended as a step-by-step guide to troubleshoot routing issues in a fairly basic OpenVPN setup.

Consider the following network plan:

  • The network at the main office location needs to be made accessible to a secondary office and to people working from home

  • The servers in the secondary office needs to be made accessible to the IT department of the main office

  • The people working from home only need to access the computer resources at the main office

For this, an OpenVPN server is set up at the main office, with the employees connecting as regular VPN clients, and with the secondary office connecting as a special client, disclosing its own network.

Drawing a...