<preface><title>Preface</title>
<para>
The Internet is now a household term in many countries. With otherwise
serious people beginning to joyride along the Information Superhighway,
computer networking seems to be moving toward the status of TV sets
and microwave ovens. The Internet has unusually high media coverage, and
social science majors are descending on Usenet newsgroups, online virtual
reality environments, and the Web to conduct research on the new
&ldquo;Internet Culture.&rdquo;
</para>

<para>
Of course, networking has been around for a long time. Connecting
computers to form local area networks has been common practice, even
at small installations, and so have long-haul links using transmission
lines provided by telecommunications companies. A rapidly growing
conglomerate of world-wide networks has, however, made joining the
global village a perfectly reasonable option for even small non-profit
organizations of private computer users. Setting up an Internet host
with mail and news capabilities offering dialup and ISDN access has
become affordable, and the advent of DSL (Digital Subscriber Line) and
Cable Modem technologies will doubtlessly continue this trend.
</para>

<para>
Talking about computer networks often means talking about Unix. Of
course, Unix is not the only operating system with network
capabilities, nor will it remain a frontrunner forever, but it has
been in the networking business for a long time, and will surely
continue to be for some time to come.
</para>

<para>
What makes Unix particularly interesting to private users is that there has
been much activity to bring free Unix-like operating systems to the PC, such
as 386BSD, FreeBSD, and Linux.
</para>

<para>
Linux is a freely distributable Unix clone for personal computers.  It
currently runs on a variety of machines that includes the Intel family
of processors, but also Motorola 680x0 machines, such as the Commodore
Amiga and Apple Macintosh; Sun SPARC and Ultra-SPARC machines; Compaq
Alphas; MIPS; PowerPCs, such as the new generation of Apple Macintosh;
and StrongARM, like the rebel.com Netwinder and 3Com Palm
machines. Linux has been ported to some relatively obscure platforms,
like the Fujitsu AP-1000 and the IBM System 3/90. Ports to other
interesting architectures are currently in progress in developers'
labs, and the quest to move Linux into the embedded controller space
promises success.
</para>

<para>
Linux was developed by a large team of volunteers across the Internet.
The project was started in 1990 by Linus Torvalds, a Finnish college
student, as an operating systems course project. Since that time,
Linux has snowballed into a full-featured Unix clone capable of
running applications as diverse as simulation and modeling programs,
word processors, speech recognition systems, World Wide Web browsers,
and a horde of other software, including a variety of excellent
games. A great deal of hardware is supported, and Linux contains a
complete implementation of TCP/IP networking, including SLIP, PPP,
firewalls, a full IPX implementation, and many features and some
protocols not found in any other operating system. Linux is powerful,
fast, and free, and its popularity in the world beyond the Internet is
growing rapidly.
</para>

<para>
The Linux operating system itself is covered by the GNU General Public
License, the same copyright license used by software developed by the Free
Software Foundation. This license allows anyone to redistribute or modify
the software (free of charge or for a profit) as long as all modifications
and distributions are freely distributable as well. The term &ldquo;free
software&rdquo; refers to freedom of application, not freedom of cost.
</para>

<sect1><title>Purpose and Audience for This Book</title>
<para>
This book was written to provide a single reference for network
administration in a Linux environment. Beginners and experienced users
alike should find the information they need to cover nearly all
important administration activities required to manage a Linux network
configuration. The possible range of topics to cover is nearly
limitless, so of course it has been impossible to include everything
there is to say on all subjects. We've tried to cover the most
important and common ones. We've found that beginners to Linux
networking, even those with no prior exposure to Unix-like operating
systems, have found this book good enough to help them successfully
get their Linux network configurations up and running and get them
ready to learn more.
</para>

<para>
There are many books and other sources of information from which you
can learn any of the topics covered in this book (with the possible
exception of some of the truly Linux-specific features, such as the
new Linux firewall interface, which is not well documented elsewhere)
in greater depth. We've provided a bibliography for you to use when
you are ready to explore more.
</para>
</sect1>

<sect1><title>Sources of Information</title>
<para>
<indexterm><primary>information on Linux</primary></indexterm>
<indexterm><primary>Linux</primary><secondary>sources of information
on</secondary></indexterm> If you are new to the world of Linux, there
are a number of resources to explore and become familiar with. Having
access to the Internet is helpful, but not essential.
</para>

<variablelist>
<varlistentry>
<term>Linux Documentation Project guides</term>
<listitem>
<para>
<indexterm><primary>Linux Documentation Project</primary></indexterm>
<indexterm><primary>LDP (Linux Documentation Project)</primary></indexterm>
<indexterm><primary>Welsh, Matt</primary></indexterm> <indexterm><primary>Wirzenius, Lars</primary></indexterm>
<indexterm><primary>Oja, Joanna</primary></indexterm>
<INDEXTERM><PRIMARY>Frampton, Steve</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Burkett, B. Scott</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Goldt, Sven</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Harper, John D.</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Meer, Sven van der</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Rusling, David A.</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Pomerantz, Ori</PRIMARY></INDEXTERM>
The Linux Documentation Project is a group of volunteers who have
worked to produce books (guides), HOWTO documents, and manual pages on
topics ranging from installation to kernel programming. The LDP works
include:

<variablelist>
<varlistentry>
<term><emphasis>Linux Installation and Getting Started</emphasis></term>
<listitem>
<para>
By Matt Welsh, et al. This book describes how to obtain, install, and use
Linux. It includes an introductory Unix tutorial and information on systems
administration, the X Window System, and networking.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>Linux System Administrators Guide</emphasis></term>
<listitem>
<para>
By Lars Wirzenius and Joanna Oja. This book is a guide to general Linux system
administration and covers topics such as creating and configuring users,
performing system backups, configuration of major software packages, and
installing and upgrading software.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>Linux System Adminstration Made Easy</emphasis></term>
<listitem>
<para>
By Steve Frampton. This book describes day-to-day administration and
maintenance issues of relevance to Linux users.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>Linux Programmers Guide</emphasis></term>
<listitem>
<para>
By B. Scott Burkett, Sven Goldt, John D. Harper, Sven van der Meer, and
Matt Welsh. This book covers topics of interest to people who wish to
develop application software for Linux.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>The Linux Kernel</emphasis></term>
<listitem>
<para>
By David A. Rusling. This book provides an introduction to the Linux
Kernel, how it is constructed, and how it works. Take a tour of your
kernel.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>The Linux Kernel Module Programming
Guide</emphasis></term>
<listitem>
<para>
By Ori Pomerantz. This guide explains how to write Linux kernel <?troff .hw modules>modules.
</para>
</listitem>
</varlistentry>

</variablelist>
</para>

<para>
More manuals are in development. For more information about the LDP
you should consult their World Wide Web server at <systemitem
role=url>http://www.linuxdoc.org/</systemitem> or one of its many
mirrors.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>HOWTO documents</term>
<listitem>
<para>
<indexterm><primary>Linux</primary><secondary>HOWTOs</secondary></indexterm>
<indexterm><primary>HOWTOs</primary></indexterm> The Linux HOWTOs are
a comprehensive series of papers detailing various aspects of the
system&mdash;such as installation and configuration of the X Window
System software, or how to write in assembly language programming
under Linux. These are generally located in the
<filename>HOWTO</filename> subdirectory of the FTP sites listed later,
or they are available on the World Wide Web at one of the many Linux
Documentation Project mirror sites.  See the Bibliography at the end
of this book, or the file <filename>HOWTO-INDEX</filename> for a list
of what's available.
</para>

<para>
You might want to obtain the <emphasis>Installation HOWTO</emphasis>, which
describes how to install Linux on your system; the <emphasis>Hardware
Compatibility HOWTO</emphasis>, which contains a list of hardware known to
work with Linux; and the <emphasis>Distribution HOWTO</emphasis>, which lists
software vendors selling Linux on diskette and CD-ROM.
</para>

<para>
The bibliography of this book includes references to the HOWTO documents
that are related to Linux networking.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term>Linux Frequently Asked Questions</term>
<listitem>
<para>
The <emphasis>Linux Frequently Asked Questions with Answers</emphasis>
(FAQ) contains a wide assortment of questions and answers about the
system. It is a must-read for all newcomers.
</para>
</listitem>
</varlistentry>
</variablelist>

<sect2><title>Documentation Available via FTP</title>
<para>
<indexterm><primary>Linux</primary><secondary>documentation</secondary></indexterm>
<indexterm><primary>documentation (Linux)</primary><secondary>via
FTP</secondary></indexterm> If you have access to anonymous FTP, you
can obtain all Linux documentation listed above from various sites,
including <systemitem role=url> metalab.unc.edu:/pub/Linux/docs
</systemitem> and <systemitem role=url> tsx-11.mit.edu:/pub/linux/docs
</systemitem>.
</para>

<para>
These sites are mirrored by a number of sites around the world.
</para>

</sect2>
<sect2><title>Documentation Available via WWW</title>
<indexterm><primary>documentation (Linux)</primary><secondary>via
WWW</secondary></indexterm>
<para>
There are many Linux-based WWW sites available. The home site for the
Linux Documentation Project can be accessed at <systemitem
role=url>http://www.linuxdoc.org/</systemitem>.
</para>

<para>
<indexterm><primary>Open Source Writers Guild</primary></indexterm>
<indexterm><primary>OSWG (Open Source Writers
Guild)</primary></indexterm> The Open Source Writers Guild (OSWG) is a
project that has a scope that extends beyond Linux. The OSWG, like
this book, is committed to advocating and facilitating the production
of OpenSource documentation. The OSWG home site is at
<systemitem role=url>http://www.oswg.org:8080/oswg</systemitem>.
</para>

<para>
Both of these sites contain hypertext (and other) versions of many Linux
related documents.
</para>

</sect2>

<sect2><title>Documentation Available Commercially</title>
<para>
<indexterm><primary>documentation
(Linux)</primary><secondary>commercial</secondary></indexterm> A
number of publishing companies and software vendors publish the works
of the Linux Documentation Project. Two such vendors are:
</para>

<literallayout>
Specialized Systems Consultants, Inc. (SSC) 
<systemitem role="url">http://www.ssc.com/</systemitem> 
P.O. Box 55549 Seattle, WA 98155-0549 
1-206-782-7733 
1-206-782-7191 (FAX) 
<systemitem role="emailaddr">sales@ssc.com</systemitem>
</literallayout>

<para>
and:
</para>

<literallayout>
Linux Systems Labs
<systemitem role="url">http://www.lsl.com/</systemitem>
18300 Tara Drive
Clinton Township, MI 48036
1-810-987-8807
1-810-987-3562 (FAX)
<systemitem role="emailaddr">sales@lsl.com</systemitem>
</literallayout>

<para>
Both companies sell compendiums of Linux HOWTO documents and other
Linux documentation in printed and bound form.
</para>

<para>
<indexterm><primary>Running Linux</primary></indexterm>
<INDEXTERM><PRIMARY>Learning Debian GNU/Linux</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Learning Red Hat Linux</PRIMARY></INDEXTERM>
<indexterm><primary>Linux in a Nutshell</primary></indexterm> O'Reilly
&amp; Associates publishes a series of Linux books. This one is a work
of the Linux Documentation Project, but most have been independently
authored. Their range includes:

<variablelist>
<varlistentry>
<term><emphasis>Running Linux</emphasis></term>
<listitem>
<para>
An installation and user guide to the system describing how to get the most
out of personal computing with Linux.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>Learning Debian GNU/Linux</emphasis></term>
<term><emphasis>Learning Red Hat Linux</emphasis></term>
<listitem>
<para>
More basic than <emphasis>Running Linux</emphasis>, these books
contain popular distributions on CD-ROM and offer robust directions
for setting them up and using them.
</para>
</listitem>
</varlistentry>

<varlistentry>
<term><emphasis>Linux in a Nutshell</emphasis></term>
<listitem>
<para>
Another in the successful "in a Nutshell" series, this book focuses on
providing a broad reference text for Linux.
</para>
</listitem>
</varlistentry>
</variablelist>

</para>
</sect2>

<sect2><title>Linux Journal and Linux Magazine</title>
<indexterm><primary>Linux Journal</primary></indexterm> 
<indexterm><primary>Linux Magazine</primary></indexterm> 
<para>
<emphasis>Linux Journal</emphasis> and <emphasis>Linux
Magazine</emphasis> are monthly magazines for the Linux community,
written and published by a number of Linux activists. They contain
articles ranging from novice questions and answers to kernel
programming internals. Even if you have Usenet access, these magazines
are a good way to stay in touch with the Linux community.
</para>

<para>
<emphasis>Linux Journal</emphasis> is the oldest magazine and is
published by S.S.C. Incorporated, for which details were listed
previously. You can also find the magazine on the World Wide Web at
<systemitem role=url>http://www.linuxjournal.com/</systemitem>.
</para>

<para>
<emphasis>Linux Magazine</emphasis> is a newer, independent
publication. The home web site for the magazine is <systemitem
role=url>http://www.linuxmagazine.com/</systemitem>.
</para>
</sect2>

<sect2><title>Linux Usenet Newsgroups</title>
<indexterm><primary>newsgroups</primary><secondary>Usenet</secondary></indexterm> 
<para>
If you have access to Usenet news, the following Linux-related newsgroups
are available:

<variablelist>
<indexterm><primary>comp.os.linux.announce</primary></indexterm> 
<varlistentry>
<term><systemitem role=newsgroup>comp.os.linux.announce</systemitem></term>
<listitem>
<para>
A moderated newsgroup containing announcements of new software,
distributions, bug reports, and goings-on in the Linux community. All
Linux users should read this group. Submissions may be mailed to
<systemitem role=emailaddr>linux-announce@news.ornl.gov</systemitem>.
</para>
</listitem>
</varlistentry>

<indexterm><primary>comp.os.linux.help</primary></indexterm>
<varlistentry>
<term><systemitem
role=newsgroup>comp.os.linux.help</systemitem></term>
<listitem>
<para>
General questions and answers about installing or using Linux.
</para>
</listitem>
</varlistentry>

<indexterm><primary>comp.os.linux.admin</primary></indexterm> 
<varlistentry>
<term><systemitem role=newsgroup>comp.os.linux.admin</systemitem></term>
<listitem>
<para>
Discussions relating to systems administration under Linux.
</para>
</listitem>
</varlistentry>

<indexterm><primary>comp.os.linux.networking</primary></indexterm> 
<varlistentry>
<term><systemitem
role=newsgroup>comp.os.linux.networking</systemitem></term>
<listitem>
<para>
Discussions relating to networking with Linux.
</para>
</listitem>
</varlistentry>

<indexterm><primary>comp.os.linux.development</primary></indexterm>
<varlistentry>
<term><systemitem role=newsgroup>comp.os.linux.development</systemitem></term>
<listitem>
<para>
Discussions about developing the Linux kernel and system itself.
</para>
</listitem>
</varlistentry>

<indexterm><primary>comp.os.linux.misc</primary></indexterm> 
<varlistentry>
<term><systemitem role=newsgroup>comp.os.linux.misc</systemitem></term>
<listitem>
<para>
A catch-all newsgroup for miscellaneous discussions that don't
fall under the previous categories.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>

<para>
There are also several newsgroups devoted to Linux in languages other
than English, such as <systemitem
role=newsgroup>fr.comp.os.linux</systemitem> in French and <systemitem
role=newsgroup>de.comp.os.linux</systemitem> in German.
</para>
</sect2>

<sect2><title>Linux Mailing Lists</title>
<para>
<INDEXTERM><PRIMARY>mailing lists</PRIMARY></INDEXTERM>
There is a large number of specialist Linux mailing lists on which you
will find many people willing to help with questions you might have.
</para>

<para>
The best-known of these are the lists hosted by Rutgers University.
You may subscribe to these lists by sending an email message formatted
as follows:

<screen>
To: majordomo@vger.rutgers.edu
Subject: anything at all
Body:

subscribe <replaceable>listname</replaceable>
</screen>
</para>

<para>
Some of the available lists related to Linux networking are:

<variablelist>
<indexterm><primary>linux-net mailing list</primary></indexterm> 
<varlistentry>
<term><systemitem role=newsgroup>linux-net</systemitem></term>
<listitem>
<para>
Discussion relating to Linux networking
</para>
</listitem>
</varlistentry>

<indexterm><primary>linux-ppp mailing list</primary></indexterm>
<varlistentry>
<term><systemitem role=newsgroup>linux-ppp</systemitem></term>
<listitem>
<para>
Discussion relating to the Linux PPP implementation
</para>
</listitem>
</varlistentry>

<indexterm><primary>linux-kernel mailing list</primary></indexterm>
<varlistentry>
<term><systemitem role=newsgroup>linux-kernel</systemitem></term>
<listitem>
<para>
Discussion relating to Linux kernel development
</para>
</listitem>
</varlistentry>
</variablelist>

</para>
</sect2>

<sect2><title>Online Linux Support</title>
<para>
<indexterm><primary>support, online</primary></indexterm> 
<indexterm><primary>help, online</primary></indexterm> 
<INDEXTERM><PRIMARY>online help</PRIMARY></INDEXTERM>
There are many ways of obtaining help online, where volunteers
from around the world offer expertise and services to assist
users with questions and problems.
</para>

<para>
<indexterm><primary>OpenProjects IRC network</primary></indexterm>
<indexterm><primary>IRC Network, OpenProjects</primary></indexterm>
The OpenProjects IRC Network is an IRC network devoted entirely to
Open Projects&mdash;Open Source and Open Hardware alike. Some of its
channels are designed to provide online Linux support services. IRC
stands for Internet Relay Chat, and is a network service that allows
you to talk interactively on the Internet to other users. IRC networks
support multiple channels on which groups of people talk. Whatever you
type in a channel is seen by all other users of that channel.
</para>

<para>
<?troff .hw openprojects>
There are a number of active channels on the OpenProjects IRC network
where you will find users 24 hours a day, 7 days a week who are
willing and able to help you solve any Linux problems you may have, or
just chat. You can use this service by installing an IRC client like
<emphasis>irc-II</emphasis>, connecting to servername <systemitem
role=sitename>irc.openprojects.org:6667</systemitem>, and joining the
<literal>#linpeople</literal> channel.
</para>
</sect2>

<sect2><title>Linux User Groups</title>
<para>
<INDEXTERM><PRIMARY>user groups</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>Linux User Groups (LUG)</PRIMARY></INDEXTERM>
<INDEXTERM><PRIMARY>LUG (Linux User Groups)</PRIMARY></INDEXTERM>
Many Linux User Groups around the world offer direct
support to users. Many Linux User Groups engage in activities such as
installation days, talks and seminars, demonstration nights, and other
completely social events. Linux User Groups are a great way of meeting other
Linux users in your area. There are a number of published lists of Linux
User Groups. Some of the better-known ones are:

<variablelist>
<varlistentry><term>Groups of Linux Users Everywhere</term>
<listitem><para> <systemitem
role=url>http://www.ssc.com/glue/groups/</systemitem>
</para></listitem>
</varlistentry>

<varlistentry><term>LUG list project</term> <listitem><para>
<systemitem role=url>http://www.nllgg.nl/lugww/</systemitem>
</para></listitem>
</varlistentry>

<varlistentry><term>LUG registry</term>
<listitem><para>
<systemitem role=url>http://www.linux.org/users/</systemitem>
</para></listitem>
</varlistentry>
</variablelist>

</para>
</sect2>

<sect2><title>Obtaining Linux</title>
<para>
<indexterm><primary>code, obtaining for</primary><secondary>Linux network</secondary></indexterm>
<indexterm><primary>Linux</primary><secondary>networks</secondary><tertiary>obtaining code for</tertiary></indexterm>
<INDEXTERM><PRIMARY>Linux distributions</PRIMARY></INDEXTERM>
<indexterm><primary>Caldera (Linux distribution)</primary></indexterm>
<INDEXTERM><PRIMARY>Corel (Linux distribution)</PRIMARY></INDEXTERM>
<indexterm><primary>Debian (Linux distribution)</primary></indexterm>
<indexterm><primary>RedHat (Linux distribution)</primary></indexterm>
<indexterm><primary>Slackware (Linux distribution)</primary></indexterm>
<indexterm><primary>SuSE (Linux distribution)</primary></indexterm>

There is no single distribution of the Linux software; instead, there
are many distributions, such as Debian, RedHat, Caldera, Corel, SuSE,
and Slackware. Each distribution contains everything you need to run a
complete Linux system: the kernel, basic utilities, libraries, support
files, and applications software.
</para>

<para>
Linux distributions may be obtained via a number of online sources, such as
the Internet. Each of the major distributions has its own FTP and web site.
Some of these sites are:

<variablelist>
<varlistentry><term>Caldera</term> <listitem><para><literallayout>
<systemitem role=url>http://www.caldera.com/</systemitem><systemitem
role=url>ftp://ftp.caldera.com/</systemitem>
</literallayout></para></listitem>
</varlistentry>

<varlistentry><term>Corel</term> <listitem><para><literallayout>
<systemitem role=url>http://www.corel.com/</systemitem><systemitem
role=url>ftp://ftp.corel.com/</systemitem>
</literallayout></para></listitem>
</varlistentry>

<varlistentry><term>Debian</term> <listitem><para><literallayout>
<systemitem role=url>http://www.debian.org/</systemitem><systemitem
role=url>ftp://ftp.debian.org/</systemitem>
</literallayout></para></listitem>
</varlistentry>

<varlistentry><term>RedHat</term>
<listitem><para><literallayout>
<systemitem role=url>http://www.redhat.com/</systemitem><systemitem role=url>ftp://ftp.redhat.com/</systemitem>
</literallayout></para></listitem>
</varlistentry>

<varlistentry><term>Slackware</term> <listitem><para><literallayout>
<systemitem role=url>http://www.slackware.com/</systemitem><systemitem
role=url>ftp://ftp.slackware.com/</systemitem>
</literallayout></para></listitem>
</varlistentry>

<varlistentry><term>SuSE</term> <listitem><para><literallayout>
<systemitem role=url>http://www.suse.com/</systemitem><systemitem
role=url>ftp://ftp.suse.com/</systemitem>
</literallayout></para></listitem>
</varlistentry>

</variablelist>

Many of the popular general FTP archive sites also mirror various
Linux distributions. The best-known of these sites are:
<literallayout>
<systemitem
role=url>metalab.unc.edu:/pub/Linux/distributions/</systemitem>
<systemitem role=url>ftp.funet.fi:/pub/Linux/mirrors/</systemitem>
<systemitem role=url>tsx-11.mit.edu:/pub/linux/distributions/</systemitem>
<systemitem role=url>mirror.aarnet.edu.au:/pub/linux/distributions/</systemitem>
</literallayout>
</para>
<?troff .Nd 7>
<para>
Many of the modern distributions can be installed directly from the
Internet.  There is a lot of software to download for a typical
installation, though, so you'd probably want to do this only if you
have a high-speed, permanent network connection, or if you just need
to update an existing installation.<footnote id="X-087-2-FNPR02">
<para>
&hellip; or you are extremely impatient and know that the 24 hours it
might take to download the software from the Internet is faster than
the 72 hours it might take to wait for a CD-ROM to be delivered!
</para>
</footnote>
</para>

<para>
Linux may be purchased on CD-ROM from an increasing number of software
vendors. If your local computer store doesn't have it, perhaps you
should ask them to stock it! Most of the popular distributions can be
obtained on CD-ROM. Some vendors produce products containing multiple
CD-ROMs, each of which provides a different Linux distribution. This
is an ideal way to try a number of different distributions before you
settle on your favorite one.
</para>

</sect2>
</sect1>

<sect1><title>File System Standards</title>
<indexterm><primary>File System Standard</primary></indexterm>
<indexterm><primary>FSSTND (File System Standard)</primary></indexterm>
<indexterm><primary>FHS (File Hierarchy Standard)</primary></indexterm>
<indexterm><primary>standards, filesystem</primary></indexterm>

<para>
In the past, one of the problems that afflicted Linux distributions,
as well as the packages of software running on Linux, was the lack of
a single accepted filesystem layout. This resulted in
incompatibilities between different packages, and confronted users and
administrators with the task of locating various files and programs.
</para>

<para>
To improve this situation, in August 1993, several people formed the
Linux File System Standard Group (FSSTND). After six months of
discussion, the group created a draft that presents a coherent file
sytem structure and defines the location of the most essential
programs and configuration files.
</para>

<para>
This standard was supposed to have been implemented by most major
Linux distributions and packages. It is a little unfortunate that,
while most distributions have made some attempt to work toward the
FSSTND, there is a very small number of distributions that has
actually adopted it fully. Throughout this book, we will assume that
any files discussed reside in the location specified by the standard;
alternative locations will be mentioned only when there is a long
tradition that conflicts with this specification.
</para>

<para>
The Linux FSSTND continued to develop, but was replaced by the Linux
File Hierarchy Standard (FHS) in 1997. The FHS addresses the
multi-architecture issues that the FSSTND did not. The FHS can be
obtained from the Linux documentation directory of all major Linux FTP
sites and their mirrors, or at its home site at <systemitem
role=url>http://www.pathname.com/fhs/</systemitem>.  Daniel Quinlan,
the coordinator of the FHS group, can be reached at <systemitem
role=emailaddr>quinlan@transmeta.com</systemitem>.

</para>
</sect1>

<sect1><title>Standard Linux Base</title>
<indexterm><primary>Linux Standard Base (LSB)</primary></indexterm>
<indexterm><primary>LSB (Linux Standard Base)</primary></indexterm>
<indexterm><primary>Linux distributions</primary><secondary>standard base</secondary></indexterm>
<para>
The vast number of different Linux distributions, while providing lots of
healthy choice for Linux users, has created a problem for software
developers&mdash;particularly developers of non-free software.
</para>

<para>
Each distribution packages and supplies certain base libraries,
configuration tools, system applications, and configuration
files. Unfortunately, differences in their versions, names, and
locations make it very difficult to know what will exist on any
distribution. This makes it hard to develop binary applications that
will work reliably on all Linux distribution bases.
</para>

<para>
To help overcome this problem, a new project sprang up called the
&ldquo;Linux Standard Base.&rdquo; It aims to describe a standard base
distribution that complying distributions will use. If a developer
designs an application to work against the standard base platform, the
application will work, and be portable to, any complying Linux
distribution.
</para>

<para>
You can find information on the status of the Linux Standard Base
project at its home web site at <systemitem role=url>
http://www.linuxbase.org/</systemitem>.
</para>

<para>
If you're concerned about interoperability, particularly of software
from commercial vendors, you should ensure that your Linux
distribution is making an effort to participate in the standardization
project.
</para>
</sect1>

<sect1><title>About This Book</title>
<para>
When Olaf joined the Linux Documentation Project in 1992, he wrote two
small chapters on UUCP and <command>smail</command>, which he meant to
contribute to the System Administrator's Guide. Development of TCP/IP
networking was just beginning, and when those &ldquo;small chapters&rdquo;
started to grow, he wondered aloud whether it would be nice to have a
Networking Guide. &ldquo;Great!&rdquo; everyone said. &ldquo;Go for it!&rdquo;
So he went for it and wrote the first version of the Networking Guide, which
was released in September 1993.
</para>

<para>
<indexterm><primary>Skahan, Vince</primary></indexterm> Olaf continued
work on the Networking Guide and eventually produced a much enhanced
version of the guide. Vince Skahan contributed the original
<command>sendmail</command> mail chapter, which was completely
replaced in this edition because of a new interface to the
<command>sendmail</command> configuration.
</para>

<para>
The version of the guide that you are reading now is a revision and
update prompted by O'Reilly &amp; Associates and undertaken by Terry
Dawson.<footnote id="X-087-2-FNPR04"><para> Terry Dawson can be
reached at <systemitem role=emailaddr>terry@linux.org.au</systemitem>.
</para>
</footnote>
Terry has been an amateur radio operator for over 20 years and has
worked in the telecommunications industry for over 15 of those. He was
co-author of the original NET-FAQ, and has since authored and
maintained various networking-related HOWTO documents. Terry has
always been an enthusiastic supporter of the Network Administrators
Guide project, and added a few new chapters to this version describing
features of Linux networking that have been developed since the first
edition, plus a bunch of changes to bring the rest of the book up to
date.
</para>

<para>
<INDEXTERM><PRIMARY>Hazel, Philip</PRIMARY></INDEXTERM>
The <command>exim</command> chapter was contributed by
Philip Hazel,<footnote id="X-087-2-FNPR05"><para>
Philip Hazel can be reached at
<systemitem role=emailaddr>ph10@cus.cam.ac.uk</systemitem>.
</para>
</footnote>
who is a lead developer and maintainer of the package.
</para>

<para>
The book is organized roughly along the sequence of steps you have to
take to configure your system for networking. It starts by discussing
basic concepts of networks, and TCP/IP-based networks in particular.
It then slowly works its way up from configuring TCP/IP at the device
level to firewall, accounting, and masquerade configuration, to the
setup of common applications such as <command>rlogin</command> and
friends, the Network File System, and the Network Information
System. This is followed by a chapter on how to set up your machine as
a UUCP node.  Most of the remaining sections is dedicated to two major
applications that run on top of TCP/IP and UUCP: electronic mail and
news.  A special chapter has been devoted to the IPX protocol and the
NCP filesystem, because these are used in many corporate environments
where Linux is finding a home.
</para>

<para>
The email part features an introduction to the more intimate parts of
mail transport and routing, and the myriad of addressing schemes you
may be confronted with. It describes the configuration and management
of <command>exim</command>, a mail transport agent ideal for use in most
situations not requiring UUCP, and <command>sendmail</command>, which is for
people who have to do more complicated routing involving UUCP.
</para>

<para>
The news part gives you an overview of how Usenet news works. It covers
INN and C News, the two most widely used news transport software packages
at the moment, and the use of NNTP to provide newsreading access to a local
network. The book closes with a chapter on the care and feeding of the most
popular newsreaders on Linux.
</para>

<para>
Of course, a book can never exhaustively answer all questions you
might have. So if you follow the instructions in this book and
something still does not work, please be patient. Some of your
problems may be due to mistakes on our part (see the section <xref
linkend="X-087-2-submitchanges">", later in this Preface), but they also may be caused by changes
in the networking software. Therefore, you should check the listed
information resources first. There's a good chance that you are not
alone with your problems, so a fix or at least a proposed workaround
is likely to be known. If you have the opportunity, you should also
try to get the latest kernel and network release from one of the Linux
FTP sites or a BBS near you.  Many problems are caused by software
from different stages of development, which fail to work together
properly. After all, Linux is a &ldquo;work in progress.&rdquo;
</para>

</sect1>

<sect1><title>The Official Printed Version</title>
<para>
In Autumn 1993, Andy Oram, who had been around the LDP mailing list
from almost the very beginning, asked Olaf about publishing this book
at O'Reilly &amp; Associates. He was excited about this book, never having
imagined that it would become this successful. He and Andy
finally agreed that O'Reilly would produce an enhanced Official
Printed Version of the Networking Guide, while Olaf retained the
original copyright so that the source of the book could be freely
distributed. This means that you can choose freely: you can get the
various free forms of the document from your nearest Linux
Documentation Project mirror site and print it out, or you can
purchase the official printed version from O'Reilly.
</para>

<para>
Why, then, would you want to pay money for something you can get for
free?  Is Tim O'Reilly out of his mind for publishing something
everyone can print and even sell themselves?<footnote
id="X-087-2-FNPR06"><para> Note that while you are allowed to print
out the online version, you may <emphasis>not</emphasis> run the
O'Reilly book through a photocopier, much less sell any of its
(hypothetical) copies.
</para>
</footnote>
Is there any difference between these versions?
</para>

<para>
The answers are &ldquo;it depends,&rdquo; &ldquo;no, definitely not,&rdquo;
and &ldquo;yes and no.&rdquo; O'Reilly &amp; Associates does take a risk in
publishing the Networking Guide, and it seems to have paid off for them
(they've asked us to do it again). We believe this project serves as a fine
example of how the free software world and companies can cooperate to produce
something both can benefit from. In our view, the great service O'Reilly is
providing to the Linux community (apart from the book becoming readily
available in your local bookstore) is that it has helped Linux become
recognized as something to be taken seriously: a viable and useful alternative
to other commercial operating systems. It's a sad technical bookstore
that doesn't have at least one shelf stacked with O'Reilly Linux books.
</para>

<para>
Why are they publishing it? They see it as their
kind of book. It's what they'd hope to produce if they contracted with
an author to write about Linux. The pace, level of detail, and style
fit in well with their other offerings.
</para>

<para>
The point of the LDP license is to make sure no one gets shut out. Other
people can print out copies of this book, and no one will blame you if you
get one of these copies. But if you haven't gotten a chance to see the
O'Reilly version, try to get to a bookstore or look at a friend's copy. We
think you'll like what you see, and will want to buy it for yourself.
</para>

<para>
So what about the differences between the printed and online versions?
Andy Oram has made great efforts at transforming our ramblings into
something actually worth printing. (He has also reviewed a few other
books produced by the Linux Documentation Project, contributing
whatever professional skills he can to the Linux community.)
</para>

<para>
Since Andy started reviewing the Networking Guide and editing the
copies sent to him, the book has improved vastly from its original
form, and with every round of submission and feedback it improves
again. The opportunity to take advantage of a professional editor's
skill is one not to be wasted. In many ways, Andy's contribution has
been as important as that of the authors.  The same is also true of
the copyeditors, who got the book into the shape you see now. All
these edits have been fed back into the online version, so there is no
difference in content.
</para>

<para>
Still, the O'Reilly version <emphasis>will</emphasis> be different. It
will be professionally bound, and while you may go to the trouble to
print the free version, it is unlikely that you will get the same
quality result, and even then it is more unlikely that you'll do it for
the price. <?troff .ne 7>Secondly, our amateurish attempts at illustration will have
been replaced with nicely redone figures by O'Reilly's professional
artists. Indexers have generated an improved index, which makes
locating information in the book a much simpler process. If this book
is something you intend to read from start to finish, you should
consider reading the official printed version.
</para>

</sect1>

<sect1 id="X-087-2-intro.outlook"><title>Overview</title>
<para>
<xref linkend="X-087-2-intro">, discusses the history of Linux and
covers basic networking information on UUCP, TCP/IP, various
protocols, hardware, and security. The next few chapters deal with
configuring Linux for TCP/IP networking and running some major
applications. We examine IP a little more closely in <xref
linkend="X-087-2-issues">, before getting our hands dirty with file
editing and the like. If you already know how IP routing works and how
address resolution is performed, you can skip this chapter.
</para>

<para>
<xref linkend="X-087-2-hardware">, deals with very basic configuration issues,
such as building a kernel and setting up your Ethernet card. The
configuration of your serial ports is covered separately in
<xref linkend="X-087-2-serial">, because the discussion does not apply
to TCP/IP networking only, but is also relevant for UUCP.
</para>

<para>
<xref linkend="X-087-2-iface">, helps you set up your machine for TCP/IP
networking.  It contains installation hints for standalone hosts with
loopback enabled only, and hosts connected to an Ethernet.  It also
introduces you to a few useful tools you can use to test and debug your
setup. <xref linkend="X-087-2-resolv">, discusses how to configure hostname
resolution and explains how to set up a name server.
</para>

<para>
<xref linkend="X-087-2-slip">, explains how to establish SLIP connections
and gives a detailed reference for <command>dip</command>, a tool that
allows you to automate most of the necessary steps.
<xref linkend="X-087-2-ppp">, covers PPP and <command>pppd</command>,
the PPP daemon.
</para>

<para>
<xref linkend="X-087-2-firewall">, extends our discussion on network
security and describes the Linux TCP/IP firewall and its configuration
tools: <command>ipfwadm</command>, <command>ipchains</command>, and
<command>iptables</command>. IP firewalling provides a means of
controlling who can access your network and hosts very precisely.
</para>

<para>
<xref linkend="X-087-2-accounting">, explains how to configure IP Accounting
in Linux so you can keep track of how much traffic is going where and who is
generating it.
</para>

<para>
<xref linkend="X-087-2-ipmasq">, covers a feature of the Linux
networking software called IP masquerade, which allows whole IP
networks to connect to and use the Internet through a single IP
address, hiding internal systems from outsiders in the process.
</para>

<para>
<xref linkend="X-087-2-appl">, gives a short introduction to setting up some
of the most important network applications, such as <command>rlogin</command>,
<command>ssh</command>, etc. This chapter also covers how services are managed
by the <command>inetd</command> superuser, and how you may restrict certain
security-relevant services to a set of trusted hosts.
</para>

<para>
<xref linkend="X-087-2-nis">, and <xref linkend="X-087-2-nfs">,
discuss NIS and NFS. NIS is a tool used to distribute administative
information, such as user passwords in a local area network. NFS
allows you to share filesystems between several hosts in your network.
</para>

<para>
In <xref linkend="X-087-2-ipx">, we discuss the IPX protocol and the NCP
filesystem. These allow Linux to be integrated into a Novell NetWare
environment, sharing files and printers with non-Linux machines.
</para>

<para>
<xref linkend="X-087-2-uucp">, gives you an extensive introduction to the
administration of Taylor UUCP, a free implementation of the UUCP suite.
</para>

<para>
The remainder of the book is taken up by a detailed tour of electronic
mail and Usenet news. <xref linkend="X-087-2-mail">, introduces you to the
central concepts of electronic mail, like what a mail address looks like, and
how the mail handling system manages to get your message to the
recipient.
</para>

<para>
<xref linkend="X-087-2-sendmail">, and <xref linkend="X-087-2-exim">, cover 
the configuration of <command>sendmail</command> and <command>exim</command>, 
two mail transport agents you can use for Linux.  This book explains both 
of them, because <command>exim</command> is easier to install for the 
beginner, while <command>sendmail</command> provides support for UUCP.
</para>

<para>

<xref linkend="X-087-2-news">, through <xref linkend="X-087-2-inn">,
explain the way news is managed in Usenet and how you install and use
C News, <command>nntpd</command>, and INN: three popular software
packages for managing Usenet news. After the brief introduction in
<xref linkend="X-087-2-news">, you can read <xref
linkend="X-087-2-cnews">, if you want to transfer news using C News, a
traditional service generally used with UUCP. The following chapters
discuss more modern alternatives to C News that use the Internet-based
protocol NNTP (Network News Transfer Protocol).  <xref
linkend="X-087-2-nntp"> covers how to set up a simple NNTP daemon,
<command>nntpd</command>, to provide news reading access for a local
network, while <xref linkend="X-087-2-inn"> describes a more robust
server for more extensive NetNews transfers, the InterNet News daemon
(INN).  And finally, <xref linkend="X-087-2-newsreaders">, shows you
how to configure and maintain various newsreaders.
</para>
</sect1>

<sect1><title>Conventions Used in This Book</title>
<para>
All examples presented in this book assume you are using a
<command>sh</command> compatible shell. The <command>bash</command> shell
is <command>sh</command> compatible and is the standard shell of all Linux
distributions. If you happen to be a <command>csh</command> user, you will
have to make appropriate adjustments.
</para>

<para>
The following is a list of the typographical conventions
used in this book:</para>

<variablelist>
<varlistentry>
<term><emphasis>Italic</emphasis></>
<listitem><para>Used for file and directory names,
program and command names, command-line options, email addresses and
pathnames, URLs, and for emphasizing new terms.</para></>
</>
<varlistentry>
<term><emphasis role=bold>Boldface</emphasis></> <listitem><para>Used for machine names, hostnames, site names, usernames and IDs, and for occasional emphasis.</></>
</>
<varlistentry>
<term><literal>Constant Width</literal></>
<listitem><para>Used in examples to show the contents of
code files or the output from commands and to indicate environment
variables and keywords that appear in code.</para></>
</>
<varlistentry>
<term><replaceable>Constant Width Italic</replaceable></>
<listitem><para>
Used to indicate variable options, keywords, or text that the user is to
replace with an actual value.
</para></>
</>
<varlistentry>
<term><userinput>Constant Width Bold</userinput></term>
<listitem><para>
Used in examples to show commands or other text that should be typed
literally by the user.
</para></listitem>
</varlistentry>
</variablelist>

<warning>
<para>
Text appearing in this manner offers a warning. You can make a
mistake here that hurts your system or is hard to recover from.
</para>
</warning>

</sect1>

<sect1 id="X-087-2-submitchanges"><title>Submitting Changes</title>
<para>
We have tested and verified the information in this book to the best of our
ability, but you may find that features have changed (or even that we have
made mistakes!). Please let us know about any errors you find, as well as
your suggestions for future editions, by writing to:
</para>

<literallayout>
O'Reilly &amp; Associates, Inc.
101 Morris Street
Sebastopol, CA 95472
1-800-998-9938 (in the U.S. or Canada)
1-707-829-0515 (international or local)
1-707-829-0104 (FAX)
</literallayout>

<?troff .Nd 7>
<para>
You can send us messages electronically. To be put on the mailing list
or request a catalog, send email to:
</para>

<literallayout>
<emphasis>info@oreilly.com</emphasis>     
</literallayout>

<para>
To ask technical questions or comment on the book, send email to:
</para>

<literallayout>
<emphasis>bookquestions@oreilly.com</emphasis>
</literallayout>

<para>
We have a web site for the book, where we'll list examples, errata,
and any plans for future editions. You can access this page at:
</para>

<literallayout>
<emphasis>http://www.oreilly.com/catalog/linag2</emphasis>
</literallayout>

<para>
For more information about this book and others, see the O'Reilly
web site:
</para>

<literallayout>
<emphasis>http://www.oreilly.com</emphasis>
</literallayout>

</sect1>

<sect1><title>Acknowledgments</title>
<para>
This edition of the Networking Guide owes almost everything to the
outstanding work of Olaf and Vince. It is difficult to appreciate the
effort that goes into researching and writing a book of this nature
until you've had a chance to work on one yourself. Updating the book
was a challenging task, but with an excellent base to work from, it
was an enjoyable one.
</para>

<para>
This book owes very much to the numerous people who took the time to
proof-read it and help iron out many mistakes, both technical and
grammatical (never knew that there was such a thing as a dangling
participle). Phil Hughes, John Macdonald, and Erik Ratcliffe all
provided very helpful (and on the whole, quite consistent) feedback on
the content of the book.
</para>

<para>
We also owe many thanks to the people at O'Reilly we've had the
pleasure to work with: Sarah Jane Shangraw, who got the book into the
shape you can see now; Maureen Dempsey, who copyedited the text; Rob
Romano, Rhon Porter, and Chris Reilley, who created all the figures;
Hanna Dyer, who designed the cover; Alicia Cech, David Futato, and
Jennifer Niedherst for the internal layout; Lars Kaufman for
suggesting old woodcuts as a visual theme; Judy Hoer for the index;
and finally, Tim O'Reilly for the courage to take up such a project.
</para>

<para>
We are greatly indebted to Andres Sep&uacute;lveda, Wolfgang Michaelis,
Michael K. Johnson, and all developers who spared the time to check
the information provided in the Networking Guide. Phil Hughes, John 
MacDonald, and Eric Ratcliffe contributed invaluable comments on the 
second edition. We also wish to thank all those who read the first version 
of the Networking Guide and sent corrections and suggestions. You can find 
a hopefully complete list of contributors in the file 
<filename>Thanks</filename> in the online distribution. Finally, this book 
would not have been possible without the support of Holger Grothe, who 
provided Olaf with the Internet connectivity he needed to make the original 
version happen.
</para>

<para>
Olaf would also like to thank the following groups and companies that 
printed the first edition of the Networking Guide and have donated
money either to him or to the Linux Documentation Project as a whole:
Linux Support Team, Erlangen, Germany; S.u.S.E. GmbH, Fuerth, Germany;
and Linux System Labs, Inc., Clinton Twp., United States, RedHat
Software, North Carolina, United States.
</para>

<para>
Terry thanks his wife, Maggie, who patiently supported him throughout
his participation in the project despite the challenges presented by
the birth of their first child, Jack. Additionally, he thanks the
<emphasis>many</emphasis> people of the Linux community who either
nurtured or suffered him to the point at which he could actually take
part and actively contribute. &ldquo;I'll help you if you promise to
help someone else in return.&rdquo;
</para>

<sect2><title>The Hall of Fame</title>

<para>
Besides those we have already mentioned, a large number of people have
contributed to the Networking Guide, by reviewing it and sending us
corrections and suggestions. We are very grateful.
</para>

<para>
Here is a list of those whose contributions left a trace in our mail folders.
</para>

<para>
Al Longyear, Alan Cox, Andres Sep&uacute;lveda, Ben Cooper, Cameron Spitzer,
Colin McCormack, D.J. Roberts, Emilio Lopes, Fred N. van Kempen, Gert
Doering, Greg Hankins, Heiko Eissfeldt, J.P. Szikora, Johannes Stille,
Karl Eichwalder, Les Johnson, Ludger Kunz, Marc van Diest, Michael
K. Johnson, Michael Nebel, Michael Wing, Mitch D'Souza, Paul
Gortmaker, Peter Brouwer, Peter Eriksson, Phil Hughes, Raul Deluth
Miller, Rich Braun, Rick Sladkey, Ronald Aarts, Swen Th&uuml;emmler,
Terry Dawson, Thomas Quinot, and Yury Shevchuk.
</para>


<indexterm><primary>electronic mail</primary><see>email</see></indexterm> 
<indexterm><primary>mail</primary><see>email</see></indexterm> 
<indexterm><primary>news (Usenet)</primary><see>news (network); Usenet</see></indexterm> 
<indexterm><primary>networks</primary><secondary>TCP/IP</secondary><see>TCP/IP</see></indexterm>
<indexterm><primary>LANs</primary><see>Local Area Networks</see></indexterm> 
<indexterm><primary>Internet Protocol</primary><see>IP</see></indexterm>
<indexterm><primary>Transmission Control Protocol</primary><see>TCP</see></indexterm>
<indexterm><primary>routing</primary><secondary>IP</secondary><tertiary>datagrams</tertiary><see>IP, routing</see></indexterm>
<indexterm><primary>serial line IP</primary><see>SLIP; PPP</see></indexterm>
<indexterm><primary>Compressed Serial Line IP</primary><see>CSLIP</see></indexterm>
<indexterm><primary>Point-to-Point Protocol</primary><see>PPP</see></indexterm>
<indexterm><primary>networks</primary><secondary>connections</secondary><see>networks, ports</see></indexterm>
<indexterm><primary>networks</primary><secondary>interfaces</secondary><see>interfaces</see></indexterm>
<indexterm><primary>access network hardware</primary><see>interfaces</see></indexterm>
<indexterm><primary>default IP route</primary><see>IP (Internet Protocol), default route</see></indexterm>
<indexterm><primary>Address Resolution Protocol</primary><see>ARP</see></indexterm>
<indexterm><primary>Reverse Address Resolution Protocol</primary><see>RARP</see></indexterm>
<indexterm><primary>Internet Control Message Protocol</primary><see>ICMP</see></indexterm> 
<indexterm><primary>Domain Name System</primary><see>DNS</see></indexterm>
</sect2>
<indexterm><primary>zones, DNS</primary><see>DNS, zones</see></indexterm>
<indexterm><primary>DNS (Domain Name System)</primary><secondary>RR</secondary><see>DNS, resource record</see></indexterm>
<indexterm><primary>IP (Internet Protocol)</primary><secondary>parallel line</secondary><see>PLIP (Parallel Line IP) protocol</see></indexterm>
<indexterm><primary>IP (Internet Protocol)</primary><secondary>serial line</secondary><see>SLIP (Serial Line IP) protocol</see></indexterm>
<indexterm><primary>Parallel Line IP</primary><see>PLIP (Parallel Line IP) protocol</see></indexterm>
<indexterm><primary>Berkeley Internet Name Domain</primary><see>BIND</see></indexterm>
<indexterm><primary>Serial Line Internet protocols</primary><seeALSO>SLIP; PPP</seeALSO></indexterm> 
<indexterm><primary>Link Control Protocol</primary><see>LCP</see></indexterm>
<indexterm><primary>Password Authentication Protocol</primary><see>PAP</see></indexterm>

<indexterm><primary>Internet Protocol Control Protocol</primary><see>IPCP</see></indexterm>
<indexterm><primary>networks</primary><secondary>interconnecting</secondary><see>internetworking</see></indexterm>
<indexterm><primary>networks</primary><secondary>UUCP</secondary><see>UUCP</see></indexterm>
<indexterm><primary>networks</primary><secondary>services</secondary><see>ports</see></indexterm>
<indexterm><primary>Remote Procedure Call</primary><see>RPC</see></indexterm>
<indexterm><primary>Network Information System</primary><see>NIS</see></indexterm>
<indexterm><primary>Network File System</primary><see>NFS</see></indexterm>
<indexterm><primary>UUCP</primary><secondary>Taylor</secondary><see>Taylor UUCP</see></indexterm> 
<indexterm><primary>Basic Networking Utilities</primary><see>Taylor UUCP, HDB</see></indexterm>
<indexterm><primary>HoneyDanBer</primary><see>Taylor UUCP, HDB</see></indexterm>
<indexterm><primary>HDB</primary><see>Taylor UUCP, HDB</see></indexterm>
<indexterm><primary>BNU (Basic Networking Utilities)</primary><see>Taylor UUCP, HDB</see></indexterm>
<indexterm><primary>Simple Mail Transfer Protocol (SMTP)</primary><see>SMTP</see></indexterm>
<indexterm><primary>routing</primary><secondary>email</secondary><see>email, routing</see></indexterm>
<indexterm><primary>email</primary><secondary>Exim</secondary><seeALSO>Exim</seeALSO></indexterm> 
<indexterm><primary>configuring</primary><secondary>Exim</secondary><see>Exim</see></indexterm>
<indexterm><primary>network news</primary><see>news (network)</see></indexterm>
<indexterm><primary>Network News Transfer Protocol</primary><see>NNTP</see></indexterm>
<indexterm><primary>news, C</primary><see>C News</see></indexterm> 
<indexterm><primary>news (network)</primary><secondary>C release</secondary><see>C News</see></indexterm>
<indexterm><primary>Trivial File Transfer Protocol</primary><see>TFTP</see></indexterm>
<indexterm><primary>filtering</primary><seeALSO>masquerade</seeALSO></indexterm>
<indexterm><primary>Unix-to-Unix Copy</primary><see>UUCP</see></indexterm>
<indexterm><primary>Netnews</primary><see>news (network); Usenet</see></indexterm>
<indexterm><primary>Internet News</primary><see>INN (Internet News)</see></indexterm>

</sect1>

</preface>

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