Wireless
Networks
FOR
DUMmIES
‰
by Barry Lewis and Peter T. Davis
Wireless
Networks
FOR
DUMmIES
‰
by Barry Lewis and Peter T. Davis
Wireless Networks For Dummies®
Published by
Wiley Publishing, Inc.
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Copyright © 2004 by Wiley Publishing, Inc., Indianapolis, Indiana
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About the Author
Barry D. Lewis (CISSP, CISM) has been in the information technology sector
for 35 years, specializing in information security since 1980. He co-founded
Cerberus Information Security Consulting in 1993 and was elevated to
President of the firm shortly thereafter. He served as Secretary and then Vice
President of the ISC(2) organization, past-President of the Toronto ISSA, and
Chairperson of the Eastern Canada ACF2 Users Group. Barry is listed in the
International Who’s Who of Entrepreneurs. Mr. Lewis lectures worldwide on
computer security and audit issues and was honored with the Best Speaker
Award at the annual Computer Associates Enterprise Wide Security & Audit
conference (ESAC), one of North America’s largest security conferences. Mr.
Lewis has written and co-authored numerous articles and seven books,
including Computer Security For Dummies, and Teach Yourself Windows 2000
Server in 21 Days. He lives near Toronto with his wife Elizabeth and son
Derek.
Peter T. Davis (CISA, CMA, CISSP, CWNA, CCNA, CMC, CISM) founded
Peter Davis+Associates (a very original name) as a firm specializing in the
security, audit, and control of information. A 29-year information systems
veteran, Mr. Davis’s career includes positions as programmer, systems analyst, security administrator, security planner, information systems auditor,
and consultant. Peter also is the past President and founder of the Toronto
ISSA chapter, past Recording Secretary of the ISSA’s International Board, and
past Computer Security Institute Advisory Committee member. Mr. Davis has
written or co-written numerous articles and 10 books, including Computer
Security For Dummies and Securing and Controlling Cisco Routers. Peter was
also the technical editor for Hacking For Dummies and Norton Internet Security
For Dummies. Peter is listed in the International Who’s Who of Professionals. In
addition, he was only the third Editor in the three-decade history of EDPACS,
a security, audit and control publication. He finds time to be a part-time lecturer in data communications at Seneca College (cs.senecac.on.ca). He
lives with his wife Janet, daughter Kelly, two cats, and a dog in Toronto,
Ontario.
Dedication
To my wife Elizabeth, who puts up with far more than I have a right to expect.
— Barry
To all my friends and enemies. Hopefully, the first group is bigger than the
second.
— Peter
Author’s Acknowledgments
We’d like to offer special thanks to Pat O’Brien, who started this rolling. Peter
worked as the technical editor for Pat on Hacking For Dummies. Thanks for
passing on Melody’s name.
Thanks to Melody Layne, acquisitions editor, for pitching the book to the editorial committee and getting us a contract. Much appreciated.
Thanks to Becky Huehls, who started us out on this project as editor but
wisely got herself re-assigned. Thanks to Kelly Ewing for picking up the ball
and running with it after Becky. Unfortunately, Kelly fumbled it, but Colleen
Totz was able to struggle with it over the goal line.
Dan DiNicolo, technical editor, is commended for his diligence in reviewing
the material. Thanks, Dan.
Peter would like to thank Kevin Beaver, Ken Cutler, Gerry Grindler, Ronnie
Holland, Carl Jackson, Ray Kaplan, Kevin Kobelsky, Carrie Liddie, Dexter
Mills Jr., and Larry Simon for responding to a request for wireless information. Thanks for answering the call for help. The provided information shows
in this book.
Barry would like to thank his co-author Peter. Always a pleasure, sir. He
would also like to acknowledge Craig McGuffin and John Tannahill who are
always there for him, as friends and business associates , and never fail to
lend a helping hand.
Publisher’s Acknowledgments
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Contents at a Glance
Introduction .................................................................1
Part I: Planning and Acquiring Your Network ................7
Chapter 1: Removing the Tethers: Entering the Wireless World .................................9
Chapter 2: If You Fail to Plan, You Plan to Fail .............................................................25
Chapter 3: Matching Wireless Technologies to Your Plan .........................................47
Part II: Implementing Your Wireless Network ..............59
Chapter 4: Getting a Quick Start with Wireless Personal Area Networks ................61
Chapter 5: Moving On to a Wireless LAN: Your Wireless Access Point ....................83
Chapter 6: Connecting Your Clients ............................................................................103
Chapter 7: Building the Multi-Zone Network .............................................................121
Chapter 8: Using Wireless on the Road to Connect to the Office ............................133
Part III: Using Your Network Securely .......................147
Chapter 9: Considering a Deadbolt: Understanding the Risks of
Wireless Networks ......................................................................................................149
Chapter 10: Designing a Secure Network ...................................................................169
Chapter 11: Maintaining Network Security ................................................................185
Chapter 12: Secure Wireless Access with Virtual Private Networking ...................209
Part IV: Keeping Your Network on the Air —
Administration and Troubleshooting ..........................229
Chapter 13: Problems with Keeping on the Air .........................................................231
Chapter 14: Bridging Networks to Manage Coverage ...............................................249
Chapter 15: Dealing with Network Throughput Issues .............................................265
Chapter 16: It’s Ten O’Clock: Do You Know Where Your Access Points Are? ........283
Part V: The Part of Tens ...........................................303
Chapter 17: Ten Administrator Tools and What They Do ........................................305
Chapter 18: Top Ten Ways to Secure Your Network .................................................313
Chapter 19: Ten Ways Wireless Is Used in Business .................................................327
Part VI: Appendixes .................................................339
Appendix A: Industry Trade Associations .................................................................341
Appendix B: Wireless Standards .................................................................................347
Appendix C: The Fundamentals of Radio Frequency.................................................353
Index .......................................................................371
Table of Contents
Introduction ..................................................................1
About This Book ..............................................................................................2
How to Use This Book ....................................................................................3
How This Book Is Organized ..........................................................................3
Part I: Planning and Acquiring Your Network ....................................3
Part II: Implementing Your Wireless Network ....................................4
Part III: Using Your Network Securely .................................................4
Part IV: Keeping Your Network on the Air —
Administration and Troubleshooting ..............................................4
Part V: The Part of Tens ........................................................................5
Part VI: Appendixes ...............................................................................5
Icons Used in This Book .................................................................................5
Where to Go from Here ...................................................................................6
Part I: Planning and Acquiring Your Network .................7
Chapter 1: Removing the Tethers: Entering the Wireless World . . . . .9
Understanding the Risks and Rewards of Going Wireless .......................10
What you risk .......................................................................................10
The benefits you gain ..........................................................................11
Applications of Wireless Networks .............................................................11
Sorting Out the Nets: Do I Need a WPAN, WLAN, or WMAN? ..................12
Let’s get personal: WPAN ....................................................................13
The holy grail of wireless networking: WLAN ..................................14
Where the rubber hits the road: WMAN ...........................................15
Using Wireless Networks ..............................................................................16
Accessing networks ............................................................................16
Extending the network ........................................................................17
Connecting buildings ..........................................................................17
Going mobile ........................................................................................18
Getting mail on the road .....................................................................19
Turning a Notion into a Network .................................................................20
Planning your wireless network ........................................................20
Installing your wireless network .......................................................20
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Wireless Networks For Dummies
Configuring a wireless network .........................................................21
Staying secure in the wireless world ................................................22
Administering and maintaining a wireless network ........................22
Convergence of Wireless Technologies —
What Will the Future Hold? ......................................................................23
Chapter 2: If You Fail to Plan, You Plan to Fail . . . . . . . . . . . . . . . . . . .25
Evaluating Your Wireless Needs ..................................................................25
What is my environment? ...................................................................26
What is my budget? .............................................................................26
How many clients do I expect? ..........................................................27
Where will they want to access the network? .................................28
What does the data look like? ............................................................28
What technology do I want to use? ...................................................29
Do I need to protect the data? ...........................................................31
What coverage do I need? ..................................................................31
Preparing for a Site Survey ..........................................................................32
Analyzing your facility ........................................................................33
Working with existing networks ........................................................33
Area coverage ......................................................................................34
Purpose and business requirements ................................................36
Bandwidth and roaming requirements .............................................37
Available resources .............................................................................37
Security needs analysis ......................................................................38
Developing a site survey checklist ....................................................38
Using Site Survey Equipment to Get It Right .............................................39
Doing That Site Survey .................................................................................41
Analyzing your indoor network .........................................................42
Analyzing your outdoor network ......................................................42
Calculating a link budget ....................................................................42
Describing Your Final Plan in a Site Survey Report ..................................45
Defining the business requirements and methodology ..................45
Documenting the requirements .........................................................46
Chapter 3: Matching Wireless Technologies to Your Plan . . . . . . . . .47
Choosing the Right Networking Hardware ................................................47
Are You Being Served? IBSS, BSS, and ESS .................................................50
Selecting the Wireless Mode ........................................................................51
Considering ad hoc mode ..................................................................51
Using infrastructure mode .................................................................52
Table of Contents
Gearing Up to Send and Receive Signals ....................................................52
Frequencies and spectrums ...............................................................53
Get the right antennae ........................................................................54
Introducing the zone — a wireless diet ............................................56
Understanding and Using Layer 2 and 3 Concepts ...................................57
Part II: Implementing Your Wireless Network ...............59
Chapter 4: Getting a Quick Start with
Wireless Personal Area Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Understanding IrDA ......................................................................................61
Installing infrared devices ..................................................................63
Using IrDA to transfer data ................................................................64
Securing IrDA .......................................................................................66
Understanding Bluetooth .............................................................................67
Adding Bluetooth capabilities ...........................................................71
Securing Bluetooth ..............................................................................74
Protecting Bluetooth networks .........................................................75
IrDA and Bluetooth Comparison .................................................................82
Chapter 5: Moving On to a Wireless LAN:
Your Wireless Access Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Parts Is Parts — Do You Have Them All? ...................................................83
Connecting and Configuring Your Access Point ........................................84
Connecting the access point ..............................................................85
Configure your browser ......................................................................86
Changing the default network settings .............................................87
Initial Setup and Testing ...............................................................................88
Deciding on initial setup options ......................................................88
Performing the advanced setup functions .......................................92
Back up your work ..............................................................................94
Turning Off the Defaults ...............................................................................94
Changing the password ......................................................................95
Changing the access point name .......................................................95
Changing security options .................................................................96
Understanding the other options ......................................................98
Configuration and setup of a Cisco Aironet 1200 ............................99
Testing the Signal ........................................................................................102
xiii