Apache is a Web server. Unless you've been under a rock for the last 10 years, you've probably heard about the World Wide Web. And, chances are you would not be holding this book if you were not already familiar with the Apache Web Server. A Web server is a piece of software that is responsible for showing you the documents you ask for when you type Web addresses into your browser.

If you're looking for a book about the Apache Native American Indian tribe, and picked up this one by mistake, you should know that the Apache Server was named out of respect for the Apache system of social organization. Apache tribe leaders were selected based on the quality of their contribution to the community. This is the same way that the Apache Software Foundation manages itself.

If you're reading this book in an attempt to determine whether you should use Apache, as opposed to one of the other Web server packages available, you should know that this book, for the most part, assumes that you've already made that decision. Although we'll briefly discuss the criteria that you should consider when choosing a server, no time is given to comparing Apache to IIS, Netscape, or any of the dozens of other Web servers out there.

Apache is a solid, dependable, reliable Web server, developed by talented, dedicated developers who are deeply concerned about the quality of the product, and the quality of the code that goes into the product. They are all amateurs, in the original sense of that word. That is, they are not doing this development because they are paid to do so (although some lucky guys are actually paid to do this). They do it because they love it and want to see something good come out of it, and see millions of people use the results of their work.

According to Netcraft (http://www.netcraft.com/), more than 60% of all Web sites on the World Wide Web are running the Apache Web Server. That's nearly 18 million Web sites. The nearest competitor, Microsoft's Internet Information Server, has just more than 20% of the market.

Now, although the fact that everyone is doing something does not necessarily mean it's a good thing to do, numbers like this seem to suggest that Apache is doing something right.

Another good measure of the server's quality is to look at who is using Apache. Companies running Apache include Thawte (http://www.thawte.com/), the premier vendor of Web security technologies; The British Monarchy (http://www.royal.gov.uk/); Cisco (http://www.cisco.com/), which manufactures more than half of the hardware on which the Internet runs; and Slashdot (http://www.slashdot.org/), a popular technology news site, which gets thousands of visitors per minute.

Granted, similar impressive references could be provided for other Web servers. It is the responsibility of every Web site admin to consider all the options, and make the best decision for their particular situation. This subject will be addressed in Chapter 1, “Getting Started,” because there are many more things to consider than just who else is using it.

This book is intended for the people that will be primarily responsible for an Apache Server—the Server Administrator. The Server Administrator is the person who installs the server, and gets called in the middle of the night when the server isn't working. He is also responsible for making daily changes to the server configuration, generating reports from the server logs, and giving people access to the portions of the Web site that they are supposed to update.

If any of those things describe what you do, or if you're just getting into this whole Web server thing and are not sure where to start, this book was written expressly with you in mind. We're taking our experiences running Web servers, both as server admins and as content providers, to give you the tools and information that you will need to avoid those calls at 3 a.m. and keep your Web site operating smoothly.

This book is not a comprehensive Apache manual, several of those are on the market. This book tries to be a little more focused than that.

Specifically, this book does not attempt to cover the aspects of the server that would be of interest to someone that wanted to work on the server code itself. For that, there is no substitute for downloading the source code and diving in.

Additionally, this book does not contain a complete listing of all the Apache directives, and their usage. If you want that, go to the Apache Web site (http://httpd.apache.org/) and start printing out the documentation. This book is intended to be a companion to the documentation, not a substitute for it. You should, however, check the Apache Web site for the most recent version of the documentation because it is being updated and improved almost every day.

I expect that some folks will wonder what significance the quotes throughout the book have. Do they have something to do with the chapter that they are attached to? Is there some overarching message conveyed by them? Or is there some secret code going on?

In college, I had a physics textbook that had strange quotes at the start of each chapter that had nothing at all to do with the chapter. Occasionally, there was a really bad pun in a quote that had to do—marginally, at least—with the content of the chapter.

I resolved then that if I ever wrote a book I would do something similar, putting in quotes that are significant to me in some way. For the most part, however, this means that you'll just have to endure my quotes without the benefit of knowing exactly why they are significant to me. If you happen to run into me at a conference, or if I'm doing training at your company, I'll try to explain a few of them to you, if you're really interested.

Code lines, directives, variables, and any text you type or see onscreen, appears in a monospaced typeface.

Placeholders appear in an italic monospace typeface. Replace the placeholder with the actual filename, parameter, or whatever element it represents.

The companion Web site to this book, which you can find at http://www.apacheadmin.com/, will contain a list of errata found in this book, as they are found, and other updates to the book's content. You will also find additional information about the topics covered in this book, one or two of the chapters, and a smattering of articles on Apache-related topics, as time permits.

There will also be a forum for discussion of Apache and related technologies, and, in particular, parts of the book on which you want clarification.