Book Image

Openswan: Building and Integrating Virtual Private Networks

By : Ken Bantoft, Paul Wouters
Book Image

Openswan: Building and Integrating Virtual Private Networks

By: Ken Bantoft, Paul Wouters

Overview of this book

<p>With the widespread use of wireless and the integration of VPN capabilities in most modern laptops, PDA's and mobile phones, there is a growing desire for encrypting more and more communications to prevent eavesdropping. Can you trust the coffee shop's wireless network? Is your neighbor watching your wireless? Or are your competitors perhaps engaged in industrial espionage? Do you need to send information back to your office while on the road or on board a ship? Or do you just want to securely access your MP3's at home? IPsec is the industry standard for encrypted communication, and Openswan is the de-facto implementation of IPsec for Linux.</p> <p>Whether you are just connecting your home DSL connection with your laptop when you're on the road to access your files at home, or you are building an industry size, military strength VPN infrastructure for a medium to very large organization, this book will assist you in setting up Openswan to suit those needs.</p> <p>The topics discussed range from designing, to building, to configuring Openswan as the VPN gateway to deploy IPsec using Openswan. It not only for Linux clients, but also the more commonly used Operating Systems such as Microsoft Windows and MacOSX. Furthermore it discusses common interoperability examples for third party vendors, such as Cisco, Checkpoint, Netscreen and other common IPsec vendors.</p> <p>The authors bring you first hand information, as they are the official developers of the Openswan code. They have included the latest developments and upcoming issues. With experience in answering questions on a daily basis on the mailing lists since the creation of Openswan, the authors are by far the most experienced in a wide range of successful and not so successful uses of Openswan by people worldwide.</p>
Table of Contents (22 chapters)
Building and Integrating Virtual Private Networks with Openswan
Credits
About the Authors
Acknowledgements
About the Reviewers
Preface

Methods of Encryption


There are a few different ways to accomplish the task of securing the local network with IPsec encryption.

Host-to-Host Mesh

If you only have a handful of machines, you could set up a full mesh of IP connections. This solution is the easiest to set up, very ugly, and a nightmare to maintain. For three servers (A, B, and C), you need to configure three IPsec tunnels (AB, AC, and BC). For four servers you need six IPsec connections, for five servers ten connections. In general, you would need (n-1) * n/2 connections for n servers. These are straightforward host-to-host IPsec connections, containing:

conn ab
left=a.b.c.d
right=a.b.c.e

Note

Sometimes host-to-host connections seem to fail in the LAN. If this happens to you, try adding type=%direct to the conn

Host-to-Gateway Setup

A slightly more advanced setup is where all machines have an IPsec connection to the default gateway, and they tunnel all traffic through this connection. However, this is not as simple as it may appear...