How, then, to begin the song of praises for the book? Let's start with its comprehensiveness. The authors--a whole passel of them, but miraculously consistent in style--deal with every subject that's central to the Unix universe. Their diligence extends even to detailed coverage of subjects (like the Domain Name System (DNS)) that many authorial squads omit. System administrators need to understand it all--it's good to see everything covered in one book. Of course, you still will need more focused texts for really complicated situations, but the coverage here will carry you a long way.

Although you probably will want to read this book cover to cover eventually, you might first look at the index, which typically will guide you to a couple of sections. First, an overview of the subject that interests you will explain what the service or feature is meant to do, what it isn't meant to do, and how (in fairly general terms) it does its job. You'll find four sections--one each on the relevant configuration facts of the four emphasized Unix variants. These sections aren't presented as explicit sequences of steps (which invariably leave the reader asking, "But, what if... " anyway), but as narratives that are interspersed with commands and configuration file listings. The approach works well, and it's made even better by the syntax summaries and conceptual diagrams that pop up now and then. --David Wall

Topics covered: Administration of Unix systems, with specific reference to Solaris 2.7, HP-UX 11.00, Red Hat Linux 6.2, and FreeBSD 3.4. Administration is a broad subject, and the authors touch on most of its aspects, including user and file operations (basic and advanced), hardware configuration, and kernel tweaking. Networking coverage includes basic connectivity, routing, server software, DNS, and security.

Preface

When we were writing the first edition of this book in the mid-1980s, we were eager to compare our manuscript with other books about UNIX system administration. To our delight, we could find only three. These days, you have your choice of at least fifty. Here are the features that distinguish our book:

We take a practical approach. Our purpose is not to restate the contents of your manuals but rather to give you the benefit of our collective experience in system administration. This book contains numerous war stories and a wealth of pragmatic advice.

We cover UNIX networking in detail. It is the most difficult aspect of UNIX system administration, and the area in which we think we can most likely be of help to you.

We do not oversimplify the material. Our examples reflect true-life situations, with all their warts and unsightly complications. In most cases, the examples have been taken directly from production systems.

We emphasize the use of software tools. Every piece of software mentioned in the text is either a standard UNIX tool or is freely available from the Internet—sometimes both, since many vendors don't do a perfect job of keeping up with new releases.

We cover all the major variants of UNIX.

Our four example systems

There have historically been two main flavors of UNIX: one from AT&T (known generically as System V) and one from the University of California, Berkeley (known as BSD). Neither AT&T nor Berkeley is still active in the UNIX marketplace, but the terms "AT&T UNIX" and "Berkeley UNIX" live on.This book covers four different operating systems:

Solaris 2.7

HP-UX 11.00

Red Hat Linux 6.2

FreeBSD 3.4 (and bits of 4.0)

We chose these systems because they are among the most popular and because they illustrate a broad range of approaches to UNIX administration. The first two systems are similar to AT&T UNIX, FreeBSD is a direct descendant of Berkeley UNIX, and Red Hat Linux is something of a mix.

We provide detailed information about each of these example systems for every topic that we discuss. Comments specific to a particular operating system are marked with the manufacturer's logo.

There are many other versions of UNIX. Most fall within the range of variation defined by these four systems, but a few (such as AIX and SCO) are so beautifully strange that they must be taken on their own terms.

The organization of this book

This book is divided into three large chunks: Basic Administration, Networking, and Bunch o' Stuff.

Basic Administration provides a broad overview of UNIX from a system administrator's perspective. The chapters in this section cover most of the facts and techniques needed to run a stand-alone UNIX system.

The Networking section describes the protocols used on UNIX systems and the techniques used to set up, extend, and maintain networks. High-level network software is also covered here. Among the featured topics are the Domain Name System, the Network File System, routing, sendmail, and network management.

Bunch o' Stuff includes a variety of supplemental information. Some chapters discuss optional software packages such as the UNIX printing system (or more accurately, systems ). Others give advice on topics ranging from hardware maintenance to the politics of running a UNIX installation.

Contact information

In this edition, we're pleased to welcome Adam Boggs, Rob Braun, Dan Crawl, Ned McClain, Lynda McGinley, and Todd Miller as contributing authors. We've turned to them for their deep knowledge in a variety of areas (and also for their ability to function amid the shifting sands of this book and its temperamental parents). Their contributions have greatly enriched the overall content of the book and the collective experience that we're able to share with you.

Please send suggestions, comments, typos, and bug reports to sa-book@admin. We answer all mail, but please be patient; it is sometimes a few days before one of us is able to respond. To get a copy of our current bug list and other late-breaking information, visit our web site at admin.

We hope you enjoy this book, and we wish you the best of luck with your adventures in system administration!Evi Nemeth
Garth Snyder
Scott Seebass
Trent R. HeinJune, 2000