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

Ciphers and Algorithms


Normally Openswan proposes all the ciphers and algorithms it supports, using a hardcoded preference. You can force which ciphers and algorithms to propose, and in which order to propose them, per connection. This can be useful for various reasons. The remote could have a buggy cipher implementation that would be otherwise selected. The remote could be a low-CPU appliance, and you wish to reduce the crypto strength. Some remotes do not respond at all after the first proposal, and you need to send the exact proposal for the remote as the first suggestion. Depending on the ciphers and algorithms that your version of Openswan and kernel support, you can define them using ike= and esp= lines. Ciphers and algorithms can either come from the KLIPS code or from the Linux CryptoAPI code. If a cipher or algorithm is available from KLIPS, it will be used instead of the CryptoAPI version.

You can use the following command to see what ciphers and algorithms are supported and loaded...