Wireless Hacking: Projects for Wi-Fi Enthusiasts

Cut the cord and discover the world of wireless hacks!

Lee Barken

• Publisher: Syngress
• Year: 2004
• Print ISBN: 9781931836371
• eBook ISBN: 9780080481784
• Topic: Computer Science
• Subtopic: Computer Science General
• Index: Computer Science

Sales of wireless LANs to home users and small businesses will soar this year, with products using IEEE 802.11 (Wi-Fi) technology leading the way, according to a report by Cahners research. Worldwide, consumers will buy 7.3 million wireless LAN nodes--which include client and network hub devices--up from about 4 million last year. This third book in the "HACKING" series from Syngress is written by the SoCalFreeNet Wireless Users Group and will cover 802.11a/b/g ("Wi-Fi) projects teaching these millions of Wi-Fi users how to "mod" and "hack" Wi-Fi access points, network cards, and antennas to run various Linux distributions and create robust Wi-Fi networks.Cahners predicts that wireless LANs next year will gain on Ethernet as the most popular home network technology. Consumers will hook up 10.9 million Ethernet nodes and 7.3 million wireless out of a total of 14.4 million home LAN nodes shipped. This book will show Wi-Fi enthusiasts and consumers of Wi-Fi LANs who want to modify their Wi-Fi hardware how to build and deploy "homebrew Wi-Fi networks, both large and small. - Wireless LANs next year will gain on Ethernet as the most popular home network technology. Consumers will hook up 10.9 million Ethernet nodes and 7.3 million wireless clients out of a total of 14.4 million home LAN nodes shipped. - This book will use a series of detailed, inter-related projects to teach readers how to modify their Wi-Fi hardware to increase power and performance to match that of far more expensive enterprise networking products. Also features hacks to allow mobile laptop users to actively seek wireless connections everywhere they go! - The authors are all members of the San Diego Wireless Users Group, which is famous for building some of the most innovative and powerful "home brew" Wi-Fi networks in the world.

Part I

Introduction to Wireless Hacking

Chapter 1

A Brief Overview of the Wireless World

Topics in this Chapter:

Introduction to Wi-Fi

The History and Basics of 802.11

Why Wi-Fi?

Introduction to Wi-Fi

Welcome to the world of “wireless magic.” 802.11 (Wi-Fi) wireless LANs have exploded onto the scene with an excitement not seen since the introduction of the Internet itself. Getting rid of the wires means getting rid of the hassle. With Wi-Fi, you can roam through your favorite coffee shop, boardroom or living room, all the while maintaining the convenience of high-speed connectivity. With Wi-Fi, life is good!

Once you’ve gone through the experience of setting up a local Wi-Fi network, your first instinct is likely to think that “bigger is better.” Expanding the coverage and increasing the network cloud enables you to share Internet resources with others as a community service. As long as you’re not breaking the law (or violating your ISP’s terms of service), you should listen to that creative instinct and start getting together with your neighbors (or others in your community) and begin planning a community wireless network! This book is all about the challenges, thrills, and adventures of such an effort, started in San Diego, and known as “SoCalFreeNet.” By offering this roadmap to you, the reader, we hope to inspire more such efforts in neighborhoods all around the world.

In this chapter, we will cover some of the Wi-Fi basics you’ll need to understand in order to complete the wireless hacks found throughout this book. We start with the history and basics of 802.11, including a review of the differences between a, b and g. Next, we cover wireless architectures and FCC rules. Finally, we include some discussion on the social benefits of community wireless networking.

The History and Basics of 802.11

The desire of people to communicate wirelessly spans many generations and technologies. Some might even argue that the ancient activity of lighting fires and using smoke signals was an early attempt to distribute a message without wires. In this book, however, we refer to the term “wireless” in the context of a modern data network. In other words: the ability to transmit and receive binary data from one location to another. A great deal of wireless data technology evolved in the late 20^th century. Unfortunately, these wireless devices were typically proprietary and expensive. Their uses included specialized applications, such as remote cash registers and warehouse inventory systems.

After spending the better part of the 1990s engaged in technical discussions, the Institute of Electrical and Electronics Engineers (IEEE) ratified the 802.11 protocol in 1997. The original protocol supported three physical layer definitions: Direct Sequence Spread Spectrum (DSSS), Frequency Hopping Spread Spectrum (FHSS), and InfraRed (IR). The supported data rates for DSSS and FHSS were 1 and 2 Mbps. These protocols operated in the 2.4 GHz unlicensed spectrum. IR remains an interesting footnote in the history of 802.11, as it never achieved any notable commercial success due to its limited range and line of sight requirements.

In 1999, the higher speed 802.11a and 802.11b protocols were ratified. 802.11b added 5.5 and 11 Mbps support using DSSS in 2.4 GHz, making it backwards-compatible with existing 1 and 2 Mbps DSSS gear (but not compatible with FHSS or IR equipment). 802.11a added Orthogonal Frequency Division Multiplexing (OFDM) as a modulation technique in the 5 GHz unlicensed spectrum, with speeds of up to 54 Mbps. In 2003, 802.11g was ratified, which provided higher speeds (up to 54 Mbps). 802.11g works by applying OFDM modulation techniques in the 2.4 GHz unlicensed spectrum. It remains backwards-compatible with 802.11b by integrating DSSS modulation (at 11, 5.5, 2, and 1 Mbps).

NOTE … WHAT IS THE WI-FI ALLIANCE?

If the IEEE publishes the 802.11 standards that define how wireless communication works, then why do we have the Wi-Fi Alliance? The answer is simple: Although standards do exist, the Wi-Fi Alliance performs interoperability testing and also serves as a non-profit, industry advocate. Once a product has successfully completed interoperability testing, it can use the “Wi-Fi” trademark on its packaging. Surprisingly, up to 25 percent of products do not pass the testing process on their first run! With the Wi-Fi seal on various products, consumers can rest assured that an Access Point purchased from one company will work with a PCMCIA card purchased from another company. This kind of guaranteed interoperability has been a major factor in the widespread adoption and prolific success of mass-produced 802.11 gear. For more information about the Wi-Fi Alliance, you can visit www.wi-fialliance.com.

IEEE Alphabet Soup

Understanding the differences between the various IEEE protocols can be daunting. Consumers often make the mistake of purchasing incompatible hardware and then returning it to the computer store when it doesn’t work. In this section, we will clear up any confusion about the differences between 802.11a, b, and g. Using this information as a guide, you will be ready to make informed and educated choices regarding the protocol best suited for your particular deployment.

802.11b

For many years, 802.11b was widely regarded as the most popular form of Wi-Fi. It utilizes frequencies in the 2.4 GHz rang...

Table of contents

• Cover image
• Title page
• Table of Contents
• Register for Free Membership to [email protected]
• Copyright
• Acknowledgments
• Technical Editor & Contributor
• Contributors
• Foreword Contributor
• Foreword
• Introduction
• Part I: Introduction to Wireless Hacking
• Part II: Hacking Projects
• Part III: Software Projects
• Part IV: Antennas and Outdoor Enclosure Projects
• Appendix A: Wireless 802.11 Hacks
• Index