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

Subnet Extrusion


With IPsec tunnels, we can do more than just connect two existing subnets with each other. We can also move a subnet, or a part of a subnet, through an IPsec tunnel to another location. This is called subnet extrusion, as shown in the diagram below:

In this figure, packets for 193.111.228.64/30 that end up on 193.110.157.1 will now be sent further via IPsec to 209.112.44.4. Response packets travel back the same way and once they reach 193.110.157.1 will be sent plaintext onto the subnet.

Imagine we want to move a small part of Sunset, the first 64 addresses, to appear at East. We would use the following conn definition:

conn sunset-extrude
	left=193.110.157.131
	leftsubnet=0.0.0.0/0
	leftrsasigkey=0sAQ1234....
	right=205.150.200.209
	rightsubnet=193.111.228.0/26
	rightrsasigkey=0sAQ5678....
	auto=start

The example uses RSA, but you can also use PSK if you want to. The important option is to define the leftsubnet= as the entire Internet. This will cause all packets on East with...