What is a Web Server?

Before we get into the

particulars of Apache, let\'s talk about what a web server is. A

web server is a program that runs

on a host computer (also, confusingly enough, called a web server) that serves

up web sites. In other words, the web server program sits around awaiting

requests from visitors\' web browsers for objects it has in its possession, and

then sends these objects back for the visitor\'s viewing pleasure. Objects that

web servers can serve include HTML documents, plain text, images, sounds,

video, and other forms of data. These objects may not necessarily exist in

static form, but instead are generated on-the-fly by programs run by the

server; CGI scripts are the most common of these programs.

Web servers and browsers

communicate using HTTP, Hypertext

Transfer

Protocol, a

simple but effective language for requesting and transmitting data over a

network. Thus, you\'ll sometimes hear web servers referred to as HTTP servers.

Web servers come in various

shapes and sizes. They run under a variety of operating systems, have varying

levels of power and complexity, and range in price from rather expensive to

free.

What\'s so special about

Apache?

Apache is:

Powerful

-- Apache\'s performance and reliability is legendary.

Feature-Rich

-- The Apache server sports a host of features, including: XML support,

server-side includes, powerful URL-rewriting, and virtual hosting, to name

but a few. We\'ll be talking about some of these features in future articles.

Modular

-- Looking for a feature not implemented in the core Apache server? Chances

are you\'ll find a module that can add the functionality you need.

Extensible

-- Can\'t find a module that suits your purposes? Well, as Apache is open

source, you can write one yourself. In fact, you can even make changes to

the inner workings of Apache. All the information you need is right there in

the source code and numerous online resources. Share your patches or modules

with the community by making them open source as well!

Popular

-- At the time of this writing, Apache holds a smidge under 60 percent of

the web server market. And, yes, popularity does count; help abounds and is

only a mailing list or newsgroup posting away.