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

IP Network Overview


Most people are familiar with IP address notation and netmasks, but in our support work and on the mailing lists we often see people using impossible configurations. Usually, this is because they have not fully understood the meaning of netmasks, the CIDR notation, or the concept of the gateway. We will give a quick explanation of these concepts for IPv4. If you are familiar with these, you can skip this part, but be aware that if you do not fully understand netmasks and gateways, you will run into problems later.

If you connect a computer to the Internet, you have to ensure that its address is unique, or else you cannot distinguish it. This is done by assigning the computer (which becomes a host on the network) an Internet Protocol address, or IP address.

An IPv4 address is a unique 32 bit number. Because humans are not fluent in binary notation, we write them in a special way, four bytes separated by dots. For example, 193.110.157.77 is the IP address of the mailing list server of the Openswan project.