Debian GNU Linux Bible

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HUNGER
If Debian GNU/Linux can do it, you can do it too . . .
Whether you’re a Linux newcomer looking for foolproof installation tips or a Debian GNU/ veteran who wants 
the scoop on the latest security enhancements, this authoritative guide delivers all the information you need 
to make the most of the Debian GNU/ “potato” release. From customizing a desktop system to troubleshooting
a network or setting up an e-commerce server, it’s the only reference you’ll ever need to become a Debian 
GNU/Linux pro. 
Inside, you’ll find 
complete coverage of
Debian GNU/Linux
• Get crystal-clear instructions for fast, painless
installation 
• Learn your way around the Linux shell, file
system, and X Window System
• Discover how easy it is to set up a LAN 
in Debian and connect to the Internet
• Make the most of Linux desktop applications,
games, and multimedia features
• Master Linux administration, from automating
system tasks to locking in security
• Find guidance on how to keep Debian current
and bug-free 
• Get the scoop on configuring servers, from
Apache and FTP to NIS and Sendmail
Shelving Category:
Linux
Reader Level:
Beginning to Advanced
System Requirements:
Intel 386 or better; 150MB+ hard drive space;
16MB+ RAM; CD-ROM drive
ISBN 0-7645-4710-0
$49.99 USA
$74.99 Canada
£39.99 UK incl. VAT
D
ebian G
N
U/Linux
Master Linux system
administration
Discover the power
of Debian’s package
management system
Build a network and
set up Linux servers
Steve Hunger
Foreword by Ian Murdock, Founder of Debian 
and now Cofounder of Progeny Linux Systems
“Steve Hunger’s book is the most comprehensive and 
up-to-date guide to Debian GNU/Linux in print.”
—Branden Robinson, Debian Developer
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4710-0 Cover 3/30/01 11:56 AM Page 1
Debian GNU/Linux® Bible
4710-0 FM.F 4/10/01 3:38 PM Page i
Debian GNU/Linux®
Bible
Steve Hunger
Hungry Minds, Inc. 
Indianapolis, IN ✦ Cleveland, OH ✦ New York, NY 
4710-0 FM.F 4/10/01 3:38 PM Page iii
Debian GNU/Linux® Bible
Published by
Hungry Minds, Inc.
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Copyright  2001 Hungry Minds, Inc. All rights
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About the Author
Steve Hunger has spent the last 10 years in the computer industry, the last four
supporting and integrating multiple platforms for a Fortune 500 Company. Having
been introduced to UNIX while attending Purdue University, he quickly latched onto
Linux as the primary platform for his startup Web hosting and development busi-
ness in 1996. He continues operating his Web business, consulting with local busi-
nesses, and freelance writing. When not conquering the world with Linux, he has
co-written and contributed to several books for Macmillan USA and Brady Games,
including work on the line of Mandrake Linux products. His latest work has been for
AOL Press called Powering Up the Internet. 
In his spare time he enjoys relaxing with his wife, riding bicycles, and tinkering with
an R/C model that is evolving into something that looks amazing like a plane. He is
also on the Board of Directors for the Central Indiana Linux Users Group 
(www.cinlug.org). Steve can be reached at steve@rhinoworld.com.
4710-0 FM.F 4/10/01 3:38 PM Page v
Credits
Acquisitions Editor
Terri Varveris
Project Editor
Gus A. Miklos
TechnicalEditor
Steve Schafer
Copy Editors
Victoria Lee O’Malley
Luann Rouff
Project Coordinator
Dale White
Graphics and Production Specialists
Amy Adrian
Sean Decker
Gabriele McCann
Kendra Span
Quality Control Technicians
David Faust
Susan Moritz
Marianne Santy
Charles Spencer
Permissions Editor
Laura Moss
Media Development Specialist
Travis Silvers
Media Development Coordinator
Marisa Pearman
Proofreading and Indexing
York Production Services, Inc.
4710-0 FM.F 4/10/01 3:38 PM Page vi
This book is dedicated to my beloved wife, Sandy. Without her love, support, and
encouragement to carry me on days I needed it, this book would not have been
possible. And to my father, who also saw me through this book.
4710-0 FM.F 4/10/01 3:38 PM Page vii
Foreword
In January 1993, while browsing USENET news one evening after work, I ranacross a thread with a subject line that read, simply, “LINUX.” I’m not sure what
it was about the word “LINUX” that made me hit Enter, but I did, and within a few
minutes, it was clear to me that I had to have it.
Unfortunately, that’s about where I hit a brick wall. I had just enough information
about Linux to whet my appetite, but there was precious little more of it to be
found. Over the course of the next few weeks, I hunted down and pieced together
the rest of what I needed to know: where to find it, how to download it, how to
install it, and what I could do with it once I had installed it.
It was a tedious process, because only scraps of information were available, and
those scraps were scattered about all over the place — a bit on a USENET group
here, a bit more on an FTP site there. And even when found and pieced together,
the scraps did not form a complete picture — I had to fill in large gaps for myself. All
in all, it was a tremendous learning experience, but it was also a tremendously frus-
trating and time-consuming experience, and if presented with the same obstacles
today, I likely would not have had the time or the inclination to overcome them.
Fortunately, becoming a Linux user is much easier today than it was in 1993. The
software itself has come a long way, and a wide range of books on the subject are
available, from installation and use to programming to administration and manage-
ment. These days, the local bookstore has all the information you need to get
started and become productive as a Linux user.
One subject that has not been covered as extensively as others, a subject near and
dear to my heart, is Debian, a project I founded not long after discovering Linux.
Debian has much to offer the Linux user — a huge selection of software, an open
development process that leads to rapid bug fixes and improvements, an unparal-
leled software management facility that allows software to be installed easily and
systems to be upgraded non-disruptively, and much more — but it has long
remained a daunting prospect to piece together the information you need to get
there.
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x Debian GNU/Linux Bible
And, so, I am extremely pleased to see books such as my friend Steve Hunger’s
Debian GNU/Linux Bible. Debian GNU/Linux Bible contains all the information you
need to know to get the most out of Debian, from installing it to using its powerful
package management system to install software and upgrade your system to setting
up a Web server and other advanced topics. With Debian GNU/Linux Bible by your
side, you will be well prepared to join the large and growing group of users that call
Debian home. I hope this book serves you well.
Ian Murdock
Founder of Debian and Co-founder of Progeny Linux Systems, Inc.
4710-0 FM.F 4/10/01 3:38 PM Page x
Preface
As Linux becomes more and more popular, resources to learn and use Linuxbecome more important. These resources help to guide, direct, and inform an
individual to make the best use of the tools available, just as a stack of boards,
nails, and a hammer don’t make a house — it takes the skilled craftsmanship of a
carpenter to turn the parts into a whole house. Debian GNU/Linux Bible gives you
the skilled guidance to help you turn the individual parts into a system.
Whom This Book Is For
This book covers the many aspects of the Debian GNU/Linux system, from the ini-
tial install of this reputable operating system to the more advanced functions like
Web servers or file servers. You do not need to have any special programming expe-
rience to use this book. You may just want to learn how to use Debian as a work-
station environment.
This book does assume some level of general computer knowledge, even though
not specifically related to Linux or UNIX. Many people get introduced to Linux after
becoming familiar with another operating system. You may be someone who wants
to learn something new, someone who wants to know what all the buzz is about
Linux, or someone who just likes the idea that the software and upgrades are free.
Whatever the reason you are reading this book, I’m sure that you will find assis-
tance in the pages of this book. You will find everything from installation to admin-
istration to server setup. This book will give you the boost needed to set up a home
or office network and to maintain that network of computers.
How This Book Is Organized
This book is organized in a progression of skill as well as function. The beginning of
the book starts out with an overview of Linux. It then progresses to the concepts
needed for average use. Then, it concludes with the concepts needed for more
intense use.
For those who are fairly new to Linux, this book will help them get their feet wet.
Some of the basic concepts, commands and tools are explained in the beginning
chapters of this book. As you become more experienced with Linux and specifically
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xii Debian GNU/Linux Bible
Debian GNU/Linux, you move into the intermediate areas of the book, namely the
middle sections. Lastly, the experienced administrator who will from time to time
need instruction on specific services can find this information in “Part III:
Administering Linux.”
Now that you have an idea of the overall layout of the book, let’s look over the book
chapter by chapter. The following will describe the contents of the book in slightly
more detail.
Part I: Getting Started
Part I provides the basic introduction to Debian GNU/Linux. The chapters in this
part start with background on Linux in general and the beginnings of the Debian
distribution; walk you through the important steps on getting Debian GNU/Linux
installed on your system; cover the essential base set of commands used to navi-
gate through the newly installed system; cover the differences between desktop
managers, desktop environments, and window managers; explain the requirements
and configuration of setting up a network and describe tools used to test, diagnose,
and evaluate the network once installed; and help you connect your system to the
Internet and explain some of the applications you’ll need for such things as e-mail,
news, and Web browsing.
Part II: Working with Debian
Chapters in Part II explain how to install additional applications on the system,
cover the features and functions of the popular Office-like application suites avail-
able to Linux, describe the intermediate commands found on the system (useful to
those interested in going on to the next step), provide examples of applications that
appeal to the senses — sight and sound alike, and list the multitude of games avail-
able for Linux (no computer user is complete with out at least trying some of the
games).
Part III: Administering Linux
The chapters in Part II cover the concerns that administrators face when managing
one system or many, deal with the programming environment found with Linux
(including the most common environments, like Perl, Tk/Tcl, and C), explain the
most amazing environment that makes Linux so powerful and how to mixthe envi-
ronment with the programming of scripts, detail the core part of the Linux
system — the kernel, and explain how to modify and create new versions of the 
kernel specifically designed for your needs.
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xiiiPreface
Part IV: Maintenance and Upgrade
Chapters in this part direct you on keeping the system updated and current to pre-
vent problems from creeping in, describe some of the hardware and how to make
changes to the system to accommodate additions, and explain why backups are
important.
Part V: Linux Server
In Part V, chapters detail how to lock down the security of a Linux system to pre-
vent intrusion; cover how Debian can be used as the first line of defense to protect
a home or office network; show you how to publish Web pages on the network or
Internet; explain how to set up a server to allow the transfer of files from any num-
ber of clients using the File Transfer Protocol; provide information on setting up a
central Network Information Server to manage a medium-sized to large network or
account; describe how to create a central point from which to share, store, and
archive files in one place; and list the servers used to handle electronic mail, one of
the most-used forms of communication among most medium-sized to large
companies.
Appendixes
The book concludes with three appendixes. 
✦ Appendix A, “What’s On the CD-ROM,” provides you with information on the
contents of the CD-ROM that accompanies this book.
✦ Appendix B, “Linux Commands,” covers many of the commands found in the
common areas on the Linux filesystem.
✦ Appendix C, “Debian Packages,” presents a list of commonly used Debian
packages with a short description of each.
System Requirements
Nearly all software has some level of requirements when referring to hardware that
it is run on. Debian GNU/Linux is no different. Even though Debian is available for
different platforms, the one used in this book is the i386-based platform. This
includes processors ranging from the Intel series (386, 486, Pentium class, and
other variations), AMD, and any of the other “Intel clone” processors. Other proces-
sor platforms will operate similarly, so this book can still operate as a reference
even though they may not be specifically referred to.
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xiv Debian GNU/Linux Bible
Beyond the core processor, the other components will be supported to varying lev-
els. For each of those, I will redirect you back to the manufacturers or to one of the
many Web site where the information about using hardware with Linux is available.
One such site is www.linuxdoc.com.
At the minimum, your systems should include at least a i486 class processor with
8MB of RAM, a 500MB hard disk and either a bootable floppy drive with CD-ROM
drive or a bootable CD-ROM drive. However, this distribution of Debian GNU/Linux
will work on systems with less. If you intend on using the i486 class processor as a
workstation, I recommend a higher standard for better response.
Conventions
There are several conventions used within this book that will help you to get more
out of it. The first is the use of special fonts or font styles to emphasize a special
kind of text; the second is the use of icons to emphasize special information.
✦ There are some situations when I’ll ask you to type something. This informa-
tion always appears in bold type like this: Type Hello World.
✦ Code normally appears on separate lines from the rest of the text. However,
there are some special situations when small amounts of code appear right in
the paragraph for explanation purposes. This code will appear in a
monospaced font like this: Some Special Code. URLs for Web sites are also
presented in monospaced font like this: http://www.microsoft.com.
✦ Definitions are always handy to have. I use italics to differentiate definitions
from the rest of the text like this: A CPU is the central processing unit for your
machine.
✦ In some code examples, I won’t have an exact value to provide so I’ll give you
an idea of what you should type by using italics and monospaced font like
this: Provide a Machine Name value for the Name field.
The following icons identify useful and important asides from the main text.
Notes help you to understand some principle or provide amplifying information. In
many cases, a Note is used to emphasize a piece of critical information that you
need.
Any time that you see a Caution, make sure that you take special care to read it.
This information is vital. I always uses the Caution to designate information that
will help you to avoid damage to your application, data, machine, or self. Never
skip the Cautions in a chapter and always follow their advice.
Caution
Note
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xvPreface
All of us like to know special bits of information that will make our job easier,
more fun, or faster to perform. Tips help you to get the job done faster and more
safely. In many cases, the information found in a Tip is drawn from experience,
rather than from experimentation or from the documentation.
There are times when information in another area of the book will help you to bet-
ter understand the current discussion. I always include the Cross-Reference icon to
indicate additional material that you might need.
Cross-
Reference
Tip
4710-0 FM.F 4/10/01 3:38 PM Page xv
Acknowledgments
Iwould first like to thank the Debian development community. Without their hardwork, high standards, and volunteer efforts, this Linux distribution would not
have the reputation it does today. So these thanks goes out to the hundreds of
those volunteers.
I would also like to thanks the two contributors to this book, John Goerzen and
Shawn Voss. John wrote the chapter on the available programming environments in
Debian. Shawn wrote the chapter on the shell environments and shell scripts.
I would also like to thank everyone who has worked to produce this book —
specifically, Terri Varveris for her efforts in planning, scheduling, and the other
details involved with getting a book like this to the shelves and Gus Miklos for all
his work making sure that what I wrote down could actually be read and under-
stood by others. I’d also like to thank Steve Schafer for his efforts editing the 
technical aspects of the book content. And a thanks go out to all the other involved
at differing levels on this book.
Thanks to all those who has had to listen to me get on my soap box about Linux
over the years — especially my wife for her patience while I spent the hours
chained to the computer working on some project or other.
4710-0 FM.F 4/10/01 3:38 PM Page xvi
Contents at a Glance
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvi
Part I: Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Chapter 1: Introduction to Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Chapter 2: Installing Debian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Chapter 3: First Steps as a Linux User . . . . . . . . . . . . . . . . . . . . . . . . . 41
Chapter 4: Choosing a GUI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Chapter 5: Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Chapter 6: Setting Up for the Internet . . . . . . . . . . . . . . . . . . . . . . . . . 113
Part II: Working with Debian . . . . . . . . . . . . . . . . . . . . . . . 131
Chapter 7: Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Chapter 8: Productivity Applications . . . . . . . . . . . . . . . . . . . . . . . . . 157
Chapter 9: Essential Tools . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 179
Chapter 10: Multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Chapter 11: Games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Part III: Administering Linux . . . . . . . . . . . . . . . . . . . . . . . . 235
Chapter 12: System Administration . . . . . . . . . . . . . . . . . . . . . . . . . . 237
Chapter 13: Scripting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Chapter 14: Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Chapter 15: Linux Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
Part IV: Maintenance and Upgrade . . . . . . . . . . . . . . . . . . . . 335
Chapter 16: Finding Updated Files . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Chapter 17: Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
Chapter 18: Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
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xviii Debian GNU/Linux Bible
Part V: Linux Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395
Chapter 19: Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
Chapter 20: Firewall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
Chapter 21: Web Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 431
Chapter 22: FTP Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
Chapter 23: Network Information System . . . . . . . . . . . . . . . . . . . . . . 485
Chapter 24: File Server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
Chapter 25: Mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
Appendix A: What’s On the CD-ROM . . . . . . . . . . . . . . . . . . . . . . . . . 539
Appendix B: Linux Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
Appendix C: Debian Packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 557
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625
GNU General Public License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 659
CD-ROM Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . 664
4710-0 FM.F 4/10/01 3:38 PM Page xviii
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvi
Part I: Getting Started 1
Chapter 1: Introduction to Linux . . . . . . . . . . . . . . . . . . . . . . . 3
Understanding the Role of the Operating System . . . . . . . . . . . . . . . . 3
History of GNU/Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Linux versus Other Operating Systems . . . . . . . . . . . . . . . . . . . . . . 6
The Word on Free Software and Open Source . . . . . . . . . . . . . . . . . . 8
What’s So Special about GNU/Linux? . . . . . . . . . . . . . . . . . . . . . . . 8
Understanding the Debian Distribution . . . . . . . . . . . . . . . . . . . . . 10
Chapter 2: Installing Debian . . . . . . . . . . . . . . . . . . . . . . . . 13
Preparing Your System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Basic Debian Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Booting off the CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
The main menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Configuring the keyboard . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Partitioning a hard disk . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Initializing and activating a swap partition . . . . . . . . . . . . . . . . 18
Initializing a Linux partition . . . . . . . . . . . . . . . . . . . . . . . . 18
Initializing the operating system kernel and modules . . . . . . . . . 19
Configuring device driver modules . . . . . . . . . . . . . . . . . . . . 20
Configuring the network . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Installing the base system . . . . . . . . . . . . . . . . . . . . . . . . . 22
Configuring the base system . . . . . . . . . . . . . . . . . . . . . . . . 23
Booting Linux directly from the hard drive . . . . . . . . . . . . . . . 24
Making a boot floppy . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Rebooting the system . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
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Configuring the Debian system . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Apt configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Using the Debian Package-Management System . . . . . . . . . . . . . . . . 31
What are deb packages? . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Adding deb packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Changing the package archive source . . . . . . . . . . . . . . . . . . 35
Gnome-apt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Installing Non-Debian Software . . . . . . . . . . . . . . . . . . . . . . . . . . 37
RPM packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
tar packages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Chapter 3: First Steps as a Linux User . . . . . . . . . . . . . . . . . . . 41
Logging In and Out of Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Basic Navigation with Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Finding special file locations . . . . . . . . . . . . . . . . . . . . . . . . 43
Finding ready-reference documentation . . . . . . . . . . . . . . . . . 45
Maneuvering through the files . . . . . . . . . . . . . . . . . . . . . . . 48
Stopping the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Using the reboot, halt, and poweroff commands . . . . . . . . . . . . 56
Using the shutdown command . . . . . . . . . . . . . . . . . . . . . . . 57
Working with the Filesystem and Related Commands . . . . . . . . . . . . . 58
Mounting drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
Chapter 4: Choosing a GUI . . . . . . . . . . . . . . . . . . . . . . . . . 63
Linux’s Graphical User Interface . . . . . . . . . . . . . . . . . . . . . . . . . 63
Deciding on a Graphical Interface . . . . . . . . . . . . . . . . . . . . . . . . 65
Installing and Configuring the X Environment . . . . . . . . . . . . . . . . . 66
X system requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Installing fonts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Installing the Display Manager . . . . . . . . . . . . . . . . . . . . . . . 69
XF86Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Starting the X server . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Starting X remotely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Managing the X server . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Installing and Using Window Managers . . . . . . . . . . . . . . . . . . . . . 79
FVWM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Enlightenment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Window Maker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
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Installing and Using Desktop Environments . . . . . . . . . . . . . . . . . . 84
GNOME . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
KDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Troubleshooting Your New Components. . . . . . . . . . . . . . . . . . . . 88
Chapter 5: Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Components of the Linux Network . . . . . . . . . . . . . . . . . . . . . . . . 91
TCP/IP Network Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
IP addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Network classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Ports and services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Netmasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Understanding Host Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Understanding Domain Names and the DNS . . . . . . . . . . . . . . . . . . 97
Setting Up the Physical Network . . . . . . . . . . . . . . . . . . . . . . . . 100
Ethernet cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Hubs and switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Setting Up the Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103
Making Changes to the Network . . . . . . . . . . . . . . . . . . . . . . . . 104
Making manual changes . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Adding IP addresses to one Ethernet card . . . . . . . . . . . . . . . 105
Troubleshooting the Network . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Using dmesg to troubleshoot . . . . . . . . . . . . . . . . . . . . . . . 106
Using ifconfig to troubleshoot . . . . . . . . . . . . . . . . . . . . . . 106
Using ping to troubleshoot . . . . . . . . . . . . . . . . . . . . . . . . 108
Using traceroute to troubleshoot . . . . . . . . . . . . . . . . . . . . 109
Using route to troubleshoot . . . . . . . . . . . . . . . . . . . . . . . 110
Chapter 6: Setting Up for the Internet . . . . . . . . . . . . . . . . . . 113
Connecting to an ISP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
Using wvdial to connect . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Using diald to connect . . . . . . . . . . . . . . . . . . . . . . . . . . . 115
Web Browsers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
E-Mail Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Balsa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Netscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
mutt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
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mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
Mail utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
News Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
PAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
Netscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
tin newsreader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
FTP Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Telnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128
Dial-in PPP Server Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Part II: Working with Debian 131
Chapter 7: Applications . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Installing Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Using the Windows Application with Linux . . . . . . . . . . . . . . . . . . 134
DOSEMU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Wine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
VMware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Plex86 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Graphics Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Gimp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
ImageMagick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Browsers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Lynx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Mozilla . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
Opera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
Netscape . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
Chapter 8: Productivity Applications . . . . . . . . . . . . . . . . . . . 157
StarOffice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
The StarOffice desktop . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Applixware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
Navigating Applixware . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
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Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Gnome Office . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Publishing documents with text files . . . . . . . . . . . . . . . . . . 174
TeX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
Groff . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
File Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Chapter 9: Essential Tools . . . . . . . . . . . . . . . . . . . . . . . . . 179
Using Text Editors in Debian GNU . . . . . . . . . . . . . . . . . . . . . . . 179
Learning to use vi . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Learning to use Emacs . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Using Commands and Programs . . . . . . . . . . . . . . . . . . . . . . . . 188
alias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
grep . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
find . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
locate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
cat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
The more program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
The less program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Automating Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196
The at command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
The batch command . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
The cron command . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198
The anacron command . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Chapter 10: Multimedia . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Listening to Audio Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203
Audio file formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Audio CDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
MP3 on Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209
Recording CDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 210
Streaming audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 212
Watching Videos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
MPEG videos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
DVD videos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Using Live Voice Chat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
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Chapter 11: Games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
System Considerations for Gaming . . . . . . . . . . . . . . . . . . . . . . . 217
Graphical interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217
Sound system requirements . . . . . . . . . . . . . . . . . . . . . . . 218
Other system demands . . . . . . . . . . . . . . . . . . . . . . . . . . 219
Playing Debian-Packaged Games . . . . . . . . . . . . . . . . . . . . . . . . 219
Adventure games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220
Arcade games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Board games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222
Card games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 223
Simulation games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224
Strategy games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
Multi-player games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
GNOME games . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228
Playing Commercial Games . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
SimCity 3000 Unlimited . . . . . . . . . . . . . . . . . . . . . . . . . . 231
Unreal Tournament . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232
Part III: Administering Linux 235
Chapter 12: System Administration . . . . . . . . . . . . . . . . . . . 237
The Roles of the System Administrator . . . . . . . . . . . . . . . . . . . . 237
The System Administrator and the Root Account . . . . . . . . . . . . . . 239
Using the su command . . . . . . . . . . . . . . . . . . . . . . . . . . 240
Using the sudo command . . . . . . . . . . . . . . . . . . . . . . . . . 241
Administering and Setting up Accounts . . . . . . . . . . . . . . . . . . . . 242
The passwd file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
The purpose of shadow passwords . . . . . . . . . . . . . . . . . . . 243
The group file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243
Employing adduser to add a user account . . . . . . . . . . . . . . . 244
The new user template — skel . . . . . . . . . . . . . . . . . . . . . . 245
Using userdel to remove a user . . . . . . . . . . . . . . . . . . . . . . 246
Restricting access to the root account . . . . . . . . . . . . . . . . . 246
Setting File and Directory Permissions . . . . . . . . . . . . . . . . . . . . . 246
Access with chmod . . . . . . . . . . . . . . . . . . . . . . . . . . . . 247
Changing user ownership with chown . . . . . . . . . . . . . . . . . . 249
Changing group membership with chgrp . . . . . . . . . . . . . . . . 250
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Using Quotas for Accounts . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Installing quotas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251
Using edquota . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252
Quota reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253
Using System Monitoring Tools . . . . . . . . . . . . . . . . . . . . . . . . . 255
Monitoring system log files . . . . . . . . . . . . . . . . . . . . . . . . 255
Disk monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 258
User monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260
Automated monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Chapter 13: Scripting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Working with Perl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265
Finding documentation for Perl . . . . . . . . . . . . . . . . . . . . . 265
Using modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 267
Using Java . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272
Using Kaffe and the Sun JDK . . . . . . . . . . . . . . . . . . . . . . . 273
Using gcj . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273
Finding documentation for Java . . . . . . . . . . . . . . . . . . . . . 274
Using Java libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275
Using Tcl/Tk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276
Finding documentation for Tcl/Tk . . . . . . . . . . . . . . . . . . . . 277
Adding Tcl/Tk libraries . . . . . . . . . . . . . . . . . . . . . . . . . . 277
Programming With Python . . . . . . . . . . . . . . . . . . . . . . . . . . . . 278
Finding documentation for Python . . . . . . . . . . . . . . . . . . . . 278
Installing Python libraries . . . . . . . . . . . . . . . . . . . . . . . . . 279
Using C/C++ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
Finding C/C++ documentation . . . . . . . . . . . . . . . . . . . . . . 284
Using C/C++ tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285
Using C/C++ libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . 286
Chapter 14: Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
What Is a Shell? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Using the shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
The Command Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
Standard input and output . . . . . . . . . . . . . . . . . . . . . . . . 295
Command substitution . . . . . . . . . . . . . . . . . . . . . . . . . . 298
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Jobs and job control . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
Escaping — special characters . . . . . . . . . . . . . . . . . . . . . . 303
Shell variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
The Shell Variants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
Bourne shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 306
C shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
Korn shell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 309
Special shell characters . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Shell Scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
Chapter 15: Linux Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . 313
Configuring the Linux Kernel . . . . . . . . . . . . . . . . . . . . . . . . . . 313
Kernel code and versions . . . . . . . . . . . . . . . . . . . . . . . . . 315
Kernel modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 316
Adding modules on the fly . . . . . . . . . . . . . . . . . . . . . . . . 317
Upgrading and updating the kernel . . . . . . . . . . . . . . . . . . . 318
Making changes to the kernel . . . . . . . . . . . . . . . . . . . . . . . 319
Compiling and installing a new kernel . . . . . . . . . . . . . . . . . . 322
Using the Linux Boot Loader . . . . . . . . . . . . . . . . . . . . . . . . . . 324
Configuring LILO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Adding the new kernel to LILO . . . . . . . . . . . . . . . . . . . . . . 326
Booting to other operating systems . . . . . . . . . . . . . . . . . . . 327
Testing and installing a new LILO configuration . . . . . . . . . . . . 327
System Initialization . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 328
Run levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 330
Initialization scripts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331
Adding and removing daemon programs . . . . . . . . . . . . . . . . 334
Part IV: Maintenance and Upgrade 335
Chapter 16: Finding Updated Files . . . . . . . . . . . . . . . . . . . . 337
Defining System Bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
Bugless software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 338
Stable versus secure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Bugs versus features . . . . . . . . . . . . . . . . . . . . . . . . . . . . 339
Getting help and reporting bugs . . . . . . . . . . . . . . . . . . . . . 340
Patches that fix bugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 341
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xxviiContents
Updating Debian Files with the Package-Management System . . . . . . . 341
Upgrading from an older Debian version . . . . . . . . . . . . . . . . 343
Upgrading over the Internet . . . . . . . . . . . . . . . . . . . . . . . 343
Upgrading from installation CD-ROMs . . . . . . . . . . . . . . . . . . 345
Chapter 17: Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . 347
Finding Linux-Compatible Hardware . . . . . . . . . . . . . . . . . . . . . . 347
Finding Linux-Compatible Laptops . . . . . . . . . . . . . . . . . . . . . . . 353
Adding Hardware to Your Linux System . . . . . . . . . . . . . . . . . . . . 356
Hard drives and CD-ROM drives . . . . . . . . . . . . . . . . . . . . . 357
Changing video cards . . . . . . . . . . . . . . . . . . . . . . . . . . . 358
Adding and changing network cards . . . . . . . . . . . . . . . . . . . 359
Adding Peripheral Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
Iomega drives (Zip, Jaz, and so on) . . . . . . . . . . . . . . . . . . . 361
Scanners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Offline printing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365
Setting up printer queues . . . . . . . . . . . . . . . . . . . . . . . . . 367
Apsfilter configuration tool . . . . . . . . . . . . . . . . . . . . . . . . 368
Chapter 18: Backups . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Planning for Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Choosing a Backup Technique . . . . . . . . . . . . . . . . . . . . . . . . . 372
Knowing what to back up . . . . . . . . . . . . . . . . . . . . . . . . . 373
Knowing what to back up with caution . . . . . . . . . . . . . . . . . 374
Choosing adequate media . . . . . . . . . . . . . . . . . . . . . . . . . 375
Choosing a backup method . . . . . . . . . . . . . . . . . . . . . . . . 377
Selecting Your Backup and Restore Tools . . . . . . . . . . . . . . . . . . . 378
amanda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
dump/restore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 382
KBackup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 385
mirrordir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387
Taper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388
tar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 389
Creating a backup using a CD-ROM . . . . . . . . . . . . . . . . . . . 390
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xxviii Debian GNU/Linux Bible
Recovering from a Crashed System . . . . . . . . . . . . . . . . . . . . . . 392
Rescue disk boot options . . . . . . . . . . . . . . . . . . . . . . . . . 393
Fixing disk problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
Part V: Linux Server 395
Chapter 19: Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397
Understanding the Need for Security . . . . . . . . . . . . . . . . . . . . . . 397
Avoiding crackers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Tools of the Trade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Authentication tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Network monitoring tools . . . . . . . . . . . . . . . . . . . . . . . . . 401
Service and integrity tools . . . . . . . . . . . . . . . . . . . . . . . . 402
Diagnostic tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402
Other helpful tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 404
Limiting the Available Services . . . . . . . . . . . . . . . . . . . . . . . . . 405
Viruses, worms, and other creepy things . . . . . . . . . . . . . . . . 407
Setting secure permissions . . . . . . . . . . . . . . . . . . . . . . . . 407
A word about passwords . . . . . . . . . . . . . . . . . . . . . . . . . 408
Tips for Securing Your System . . . . . . . . . . . . . . . . . . . . . . . . . 409
The compromised system . . . . . . . . . . . . . . . . . . . . . . . . . 412
Sources for additional information . . . . . . . . . . . . . . . . . . . . 413
Chapter 20: Firewall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
Protecting a Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415
Hardware Requirements and Preparations . . . . . . . . . . . . . . . . . . 416
Adding a Second Network Card . . . . . . . . . . . . . . . . . . . . . . . . . 417
Using ipchains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419
Masquerading a Private Network . . . . . . . . . . . . . . . . . . . . . . . . 422
Configuring a Firewall with PMFirewall . . . . . . . . . . . . . . . . . . . . 423
Locking Down the Firewall . . . . . . . . . . . . . . . . . . . . . . . . . . . . 425
Squid Proxy Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 426
Accessing the Internet through a Firewall/Proxy . . . . . . . . . . . . . . . 428
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xxixContents
Chapter 21: Web Server . . . . . . . . . . . . . . . . . . . . . . . . . . 431
Introduction to Apache Web Server . . . . . . . . . . . . . . . . . . . . . . 431
Installing the Apache Server . . . . . . . . . . . . . . . . . . . . . . . . . . . 432
Configuration files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 434
The httpd.conf configuration file . . . . . . . . . . . . . . . . . . . . . 434
The srm.conf configuration file . . . . . . . . . . . . . . . . . . . . . . 444
The access.conf configuration file . . . . . . . . . . . . . . . . . . . . 453
Controlling the daemon . . . . . . . . . . . . . . . . . . . . . . . . . . 456
Monitoring the Web server . . . . . . . . . . . . . . . . . . . . . . . . 456
Setting Controls for Web Pages . . . . . . . . . . . . . . . . . . . . . . . . . 457
.htaccess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 458
htpasswd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459
Enabling Virtual Hosting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 460
Chapter 22: FTP Server . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
All About FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463
Anonymous FTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
Installing and Configuring an FTP Server . . . . . . . . . . . . . . . . . . . 465
The ftpd server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465
The wu-ftpd server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 466
The proftpd server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 472
Administering an FTP Server . . . . . . . . . . . . . . . . . . . . . . . . . . 475
Using FTP Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
The ftp client . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 476
The ncftp client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 478
The xftp client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
gftp clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 482
Browsers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483
Chapter 23: Network Information System . . . . . . . . . . . . . . . 485
The Network Information System . . . . . . . . . . . . . . . . . . . . . . . . 485
An overview of NIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 486
Configuring a Master NIS Server . . . . . . . . . . . . . . . . . . . . . . . . 487
Configuring a NIS Client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489
Configuring a NIS Slave Server . . . . . . . . . . . . . . . . . . . . . . . . . 490
Using NIS Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 491
Administering NIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 492
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xxx Debian GNU/Linux Bible
Chapter 24: File Server . . . . . . . . . . . . . . . . . . . . . . . . . . . 495
Using the Network File System . . . . . . . . . . . . . . . . . . . . . . . . . 496
Installing and running NFS . . . . . . . . . . . . . . . . . . . . . . . . 496
Setting up the NFS shares in /etc/exports . . . . . . . . . . . . . . . . 497
Mounting an NFS share automatically . . . . . . . . . . . . . . . . . . 499
Mounting an NFS file system manually . . . . . . . . . . . . . . . . . 501
Unmounting an NFS filesystem . . . . . . . . . . . . . . . . . . . . . . 502
Sharing Files Using Samba . . . . . . . . . . . . . . . . . . . . . . . . . . . . 502
Installing Samba . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
Configuring Samba . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 503
Testing the Samba server . . . . . . . . . . . . . . . . . . . . . . . . . 511
Configuring Samba with SWAT . . . . . . . . . . . . . . . . . . . . . . 512
Configuring Samba with gnosamba . . . . . . . . . . . . . . . . . . . 513
Checking the network with smb-nat . . . . . . . . . . . . . . . . . . . 514
Connecting to a Samba server from Linux . . . . . . . . . . . . . . . 514
Connecting to a Samba server from Windows . . . . . . . . . . . . . 515
Sharing files between Linux and Windows machines . . . . . . . . . 515
Chapter 25: Mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 517
Understanding Internet E-Mail Protocols and Standards . . . . . . . . . . 517
exim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 519
Using Sendmail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525
Questions during installation . . . . . . . . . . . . . . . . . . . . . . . 525
Alternatively configuring sendmail . . . . . . . . . . . . . . . . . . . 528
Testing and using sendmail . . . . . . . . . . . . . . . . . . . . . . . . 529
General Mail Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . 530
E-mail aliases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 530
Forwarding your mail . . . . . . . . . . . . . . . . . . . . . . . . . . . 531
Virtual mail server . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 532
DNS and Internet mail . . . . . . . . . . . . . . . . . . . . . . . . . . . 533
Using mailing lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
Setting Up POP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534
Installing and configuring POP . . . . . . . . . . . . . . . . . . . . . . 534
Testing POP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535
Setting Up IMAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
Installation and configuration . . . . . . . . . . . . . . . . . . . . . . 536
Testing IMAP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 536
Getting Help . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 537
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xxxiContents
Appendix A: What’s On the CD-ROM . . . . . . . . . . . . . . . . . . . 539
Using the CD with Linux . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
What’s On the CD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 539
Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540
Source code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 540
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 541
Appendix B: Linux Commands . . . . . . . . . . . . . . . . . . . . . . 543
Linux Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 543
bin commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 544
sbin commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 545
usr commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 547
Appendix C: Debian Packages . . . . . . . . . . . . . . . . . . . . . . . 557
Administration utilities . . . . . . . . . . . . . . . . . . . . . . . . . . 557
Base utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 562
Communication programs . . . . . . . . . . . . . . . . . . . . . . . . 565
Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 566
Graphics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 571
Mail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577
Miscellaneous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 582
Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 588
Newsgroups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599
Other OS’s and file systems . . . . . . . . . . . . . . . . . . . . . . . . 600
Shells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603
Utilities for I/O and storage . . . . . . . . . . . . . . . . . . . . . . . . 609
Web software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 616
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625
GNU General Public License. . . . . . . . . . . . . . . . . . . . . . . . . . 659
CD-ROM Installation Instructions . . . . . . . . . . . . . . . . . . . . . . . 664
4710-0 FM.F 4/10/01 3:38 PM Page xxxi
Getting Started
✦ ✦ ✦ ✦
In This Part
Chapter 1
Introduction to Linux
Chapter 2
Installing Debian
Chapter 3
First Steps as a 
Linux User
Chapter 4
Choosing a GUI
Chapter 5
Networking
Chapter 6
Setting Up for the
Internet
✦ ✦ ✦ ✦
P A R T
II
4710-0 pt1.F 4/10/01 11:19 AM Page 1
Introduction to
Linux
Welcome to the Debian GNU/Linux Bible where youcan find hints, tips, and helpful instructions on most
areas of this robust operating system. As you begin to learn
more about this distribution of the Linux operating system,
I’m sure you will find that you have made an excellent choice.
Debian GNU/Linux is one of the best-kept secrets from the
general public.
In case you were wondering, GNU stands for GNU’s Not
UNIX, which still doesn’t answer the question of the defini-
tion of GNU. That’s the best I can come up with.
This chapter covers the background of Linux, what makes it
special, and how Debian compares to other operating sys-
tems. You will discover the true meaning behind free software
and why it is so important to Debian.
Before you begin to read about the origins of this great operat-
ing system, I open with a definition of the operating system.
This helps to define how you look at the accomplishments
described later.
Understanding the Role of the
Operating System
The operating system controls the interaction between hard-
ware and thesoftware applications. The hardware consists of
the processor, hard drives, video cards, sound cards, and more.
Each processor has built into it a language that only it under-
stands, plus each manufacturer creates a different language for
its processor. For instance, an Intel x86 processor uses a differ-
ent internal language than, say, a Motorola 68000 processor.
Therefore, any software must be complied (converted into the
Note
11C H A P T E R
✦ ✦ ✦ ✦
In This Chapter
Understanding the
role of the operating
system
Understanding the
history of Linux
Considering the story
behind Open Source
Comparing Linux to
other operating
systems
Using the Debian
Distribution
✦ ✦ ✦ ✦
4710-0 ch01.F 4/10/01 11:20 AM Page 3
4 Part I ✦ Getting Started
processor language) or customized for the processor (often referred to as the com-
puter platform). Some of the platforms include:
✦ x86 (Intel [386, 486, Pentium, Pentium II, Pentium III, Celeron], AMD [K6-2,
Athlon, or others equivalent to the Intel line])
✦ Alpha (Was DEC, Now Compaq)
✦ Power PC, also known as PPC (Motorola/IBM Power PC)
✦ M68k (Motorola 68000 series)
✦ Sparc (Sun Microsystems’s SPARCstation)
The core component to the operating system is called the kernel in UNIX and UNIX-
like operating systems. The kernel communicates with the basic computer hard-
ware like the microprocessor, memory, and device controllers. All interaction
between the hardware and any programs must be negotiated through the kernel.
The kernel takes care of translating the requests into the form the particular device
speaks. This includes everything from drawing a picture to saving a file to a floppy
to printing a document. In addition to the kernel, the user interface, device drivers,
file system, and system services complete the whole operating system and make it
functional for someone to use.
✦ The user interface makes it possible for the individual to interact with the
computer to issue commands, launch programs, and generally control the
computer. This usually starts as a command-line interface and later becomes
some kind of graphical interface. One example of the interface is the shell
which allows commands to be typed in and the output gets displayed to the
screen in text form. Chapters 4 and 14 cover the graphical interface and shell
interface respectively.
✦ The device drivers allow the kernel to talk to the various devices, such as
hard drives and modems, which are connected to the computer. Each hard-
ware device speaks its own language, and the operating system must be capa-
ble of interacting with it. In order for a specific piece of hardware to be used,
like the mouse, hard drive or sound card, the corresponding driver must be
installed for it to get used. See Chapter 17 for more information about hard-
ware or Chapter 15 for the kernel details.
✦ The information for the operating system — such as programs, data, and
such — gets stored to a disk. The filesystem sets the method that the informa-
tion gets stored. Different operating systems use different methods of storing
their data. For instance Windows 3.1 uses File Allocation Tables (FAT) fir its
filesystem. Newer versions of Windows like 95 and 98 use a more advanced
version called FAT32. And Windows NT uses NTFS for its filesystem. Not all of
these filesystems are compatible with all operating systems, even among the
Windows family. Windows NT can read FAT and NTFS, but not FAT32. Like
wise, Windows 95 and 98 can read FAT and FAT32, but not NTFS. Linux uses
EXT2, but can read FAT and FAT32 using the VFAT driver. You can learn more
about this scattered through the book.
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5Chapter 1 ✦ Introduction to Linux
✦ When the computer starts up, some functions, features, or services start to
manage the system. For instance, when Linux first starts, it loads the filesys-
tems, network interfaces, and any background services known as daemons.
When the filesystem loads, it assigns what drives get used. The network inter-
face gets initialized and configured to communicate on the network. 
A daemon is a program that runs in the background without anyone being aware
of it until it is needed. (This is referred to as services in the Windows NT world.) For
instance, a Web server (Chapter 21) runs in the background because it was
designed to work with out human intervention.
Now that you have a better understanding of what an operating system is, you can
move on to see what Linux is all about.
History of GNU/Linux
Free operating systems are not a new concept in the computer world,. (The aca-
demic versions of UNIX, Slackware, and FreeBSD come to mind.) Then a student of
the University of Helsinki, Linus Torvalds announced in 1991 that he had created a
very experimental operating system core called a kernel, based on a clone of UNIX
called Minux. This new operating system kernel later became known as Linux.
Torvolds chose this UNIX variant because of the well-respected stability, design and
functionality of the UNIX operating system developed by Bell Laboratories.
This new operating system kernel was refined for maximum performance on the Intel
386 microprocessor, which made this new Linux kernel platform specific. This gener-
ated criticism from some corners of the UNIX software world. Traditionally, UNIX was
independent of platform, meaning that you could use the softeware with different
computer processors without much trouble. This didn’t stop Torvalds from continu-
ing to develop his kernel. His efforts eventually led him to the free software commu-
nity where programmers got behind his efforts and contributed to the new kernel.
However, long before Torvalds started work on his Linux kernel, Richard M.
Stallman left his job at the MIT Artificial Intelligence Lab to develop a UNIX-like
operating system. He formed the Free Software Foundation and developed the GNU
General Public License (GPL). Stallman began working on various software pro-
grams for his GNU operating system project. (By the way, GNU is pronounced with
a hard G, ga-nu) By 1991, he had most of the software pieces of the GNU operating
system complete with the exception of the kernel. In 1990, he started working on
the kernel and named it HURD (Hird of UNIX-Replacing Daemons). Hird stands for
Hurd of Interfaces Representing Depth. According to an interview with Stallman,
people interested in the GNU project began to put Torvald’s Linux kernel with
Stallman’s GNU operating system to form the GNU/Linux operating system.
The HURD project is a rewrite of the UNIX kernel. The difference between this ker-
nel and others is that it has an object-oriented structure that enables you to
change, add, or remove components without major rewrites of the entire kernel.
Currently, HURD only works with the Intel i386 and the last official release was
Note
Note
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6 Part I ✦ Getting Started
back in 1997. However, it remains an active project. Had the Linux kernel been
available in 1990, Stallman says they would not have started their own.
In truth, from its adoption as an operating system, the rightful name of Linux is
really GNU/Linux. Linux is really only the kernel (the core component) and GNU
contains the supporting applications around the kernel that make it functional.
These supporting applications include the user interface and all other applications
(editors, Most refer to GNU/Linux as simply Linux, which you may even see in this
book from time to time for the sake of brevity. Please understand I mean no disre-
spect to the developers.
Linux versus Other Operating Systems
When Bill Gates, founder of Microsoft, made his deal with IBM to include his disk oper-
ating system (DOS) with IBM personal computers, his goal was to put a computer in
every home. Today many homes do have personal computers (PCs), and most use
some type of Microsoft operating system. Until recently, a Microsoft operating systemwas your only preinstalled choice when purchasing a new personal computer. Now,
many name brand PC manufacturers — such as Dell, Compaq, and others — offer other
operating systems. Table 1-1 shows a list of many of the operating systems.
Table 1-1
Popular PC operating systems and platforms
Operating System Platform
Linux (Debian) Intel x86, PowerPC, M68k, Alpha, Sparc, ARM
Windows 95/98 Intel x86
Windows NT/2000 Intel x86, PPC
MacOS PPC
Be OS Intel x86
OS/2 Warp Intel x86, Alpha
Solaris Sparc, Intel x86
As you can see from Table 1-1, no other operating system can be used with nearly
as many platforms as Linux can. Plans are in the works by Linux developers to
include others, such as sparc64, MIPS, and PS-RISK. Development teams of program-
mers from all around the world are credited for this outstanding growth.
Even though the Windows 95/98 operating system gained vast popularity due to its
professed user friendliness, GNU/Linux has made steady improvements to reach
the same level of user friendliness. In 1999, the growth rate seen by Linux exceeded
Note
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7Chapter 1 ✦ Introduction to Linux
the growth of Windows NT. Despite the strong marketing power, available
resources, and influence of the big boys, the cheap (by price only) operating sys-
tem called Linux is taking the world by storm.
Table 1-2 lists some significant differences between Linux and the other operating
systems:
Table 1-2
Benefits of Linux
Benefit Description
Costs nothing Linux is the only operating system that costs nothing. All others listed
have some purchasing fee ranging from just under $100 to several 
hundred dollars. For a business with several servers and 
workstations, this can add up fast.
Downloadable With a fast Internet connection, you can have your operating system 
available in a short period of time. No need to order it, have it 
shipped, or visit a local computer dealer to get the copies you need.
Freely distributed Make as many copies of Debian GNU/Linux as you want or need. 
There is no copyright with GPL software except that the source code 
must be included. Other operating systems require a purchased 
license for each installation.
Built by volunteers Other operating systems are company creations in which all the 
work is either contracted or programmed in-house. Volunteers make
up the primary programming body of Linux. Some companies 
contribute to the cause for the benefit of the whole. This volunteer 
principle contributes to its overall stability.
Source code available When you buy an operating system off the shelf, you only get the 
compiled version ready to run straight out of the box. If there is a 
problem or a minor change you want to make, you have no chance 
to make it because of no available source code. Linux encourages 
individual adjustments, modifications, and fixes because the source
is always available. As a result of the available source code, fixes to 
problems can take place literally overnight.
Reliable Though this may not be unique to Linux, it is important nonetheless. 
Linux is very stable as are some of the other operating systems. I
have known Linux servers to run without needing to be restarted for 
months at a time (and then only for hardware maintenance). In
contrast, some Windows NT servers need to be restarted every day 
to ensure their reliability.
Flexible With the vast numbers of programs available for Linux, its uses can 
range from a single task as a monitor, to uses as a workstation for 
calculating advanced mathematical formulas or graphics. You can 
use Linux as an Internet router, firewall, proxy, Web server, or mail 
server that is as powerful as any on the open market.
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8 Part I ✦ Getting Started
The Word on Free Software and Open Source 
The Free Software Foundation believes, of course, that software should be free. This
includes the source code for the executable programs. When they say free, they
mean it. 
The foundation, which developed the GNU General Public License (GPL), promotes
sharing of free software (including the source code). The purpose of this is to allow
the programming community to make changes to the code. According to the GPL,
no software that claims this license can be distributed without the source code.
When source code is included, the programming community can respond to
defects, bugs, and cracks faster. A fix for a commercial operating system can take
up to six months to be released, compared to a few days in the Linux world.
Just because software is free and the source gets included doesn’t mean that it’s a
free-for-all on the program. Once a developer releases GPL software, any licensing
changes made to that software must be made with the consent of the author.
However, you can freely distribute, modify, and use it. Although most software
released with Debian uses the GPL and is free, some software discussed in this
book and found elsewhere is not free as it is sold commercially. However, most soft-
ware for Linux is free.
The Open Source community differs slightly from the Free Software movement,
although both desire to see freely available software. The Open Source movement is
less concerned with whether anyone makes a profit along the way, but more con-
cerned with the distribution of free software. Eric Raymond cofounded the Open
Source Software Group out of a concern that businesses weren’t getting the word. As a
result of his efforts, some companies have adopted the Open Source philosophy. One
such company, Cygnus Solutions, produced the GNUPro Developers Kit as an Open
Source product. Red Hat acquired this product, which is now called GNUPro ETS. 
Having corporations involved in the development and promotion of Linux helps
everyone. Companies bring training, certification, and support to an otherwise hobby
operating system. Without this kind of support, many people (and companies) stay
away from a product to avoid its potential failure of an unknown future. As more
companies get behind a system — for better or worse — it gains more credibility in
the minds of businesses. Therefore, having companies involved in the development
of Linux is a good thing.
What’s So Special about GNU/Linux?
Stallman’s dream of having an operating system free from commercial purse strings
came true with the completion of the kernel by Torvalds. As the community of pro-
grammers grew, so did the draw to GNU/Linux. The metamorphosis of the operating
system grew to gain the attention of the world. 
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9Chapter 1 ✦ Introduction to Linux
More and more people started joining the Linux movement by adopting GNU/Linux
as their operating system of choice. Many migrated to it looking for a stable envi-
ronment from which to create programs, while others sought something that
wouldn’t crash when performing simple daily tasks like word processing. Both
groups of users were pleasantly surprised with GNU/Linux.
With the popularity of GNU/Linux increasing, some programmers created special
distributions of the operating systems by adding in their own special programs as
enhancements. You can easily obtain some of these systems, while others encour-
age the purchase of their packages. Still others include software at a price, which
dilutes the openness of the source. Table 1-3 lists some of the more popular Linux
distributions. All can be purchased from store (except Debian) or downloaded from
a site like www.linuxiso.org where all you have to do is burn the distribution
image to a CD for you own copy.
Table 1-3
Linux distributions and Web sites
Distribution Web Site
Debian GNU/Linux www.debian.org
Red Hat www.redhat.com
SuSE www.suse.org
Caldera OpenLinux www.caldera.com
Slackware Linux www.slackware.com
Linux-Mandrake www.mandrake.com
Corel Linux linux.corel.com
Storm Linux www.stormix.com
Turbo Linux www.turbolinux.com
Some of these distributions listed