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

Dynamic IP Addresses


In our examples so far, we have assumed that the IP addresses of the IPsec endpoints are known and do not change. This is not always the case, though often the VPN server at the office will be static, and only the connecting clients will use various unknown IP addresses.

Hostnames

First, you could use a fully qualified domain name (FQDN) instead of an IP address. This way, if one endpoint changes IP address, as long as the DNS is changed, changes on all the connecting peers will not be necessary. Even though DNS is not secure, and anyone can spoof DNS answers, it will suffice for our use here, because all our peers have already exchanged their public RSA key or PSK. Even if some attacker spoofs the DNS, no information could leak, because the IPsec tunnel to the rogue endpoint would never get established. It is missing vital credentials—either the private RSA key or the PSK. So we can safely use:

left=west.testbed.xelerance.net
right=east.testbed.xelerance.net

Openswan would...