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

Routing Decisions


So far we have made decisions on where to send packets to based on where they need to go to. This is called destination-based routing, and is the most common type of routing on leaf nodes. Routing decisions can, however, be made based on many criteria. Another common type of routing is source-based routing. For those familiar with the 'funny routes' with Openswan, these two half default routes into the IPsec network device make sure all packets are processed by Openswan to get encrypted. This mechanism predates proper source routing and will be replaced soon. Linux source routing is performed using the ip rule command.

Routing of packets to non-local machines is a rather dynamic process. Hosts on the Internet keep changing locations from a network topology point of view. If there is an outage, a different route will be taken. But there are more things to consider when routing packets, and the most common criterion on backbone routers these days sadly is money. Packets will be routed based on the cost. Some call this hot-potato routing, which means "get rid of the packet as soon as you can", because that is most often the cheapest solution.