Apache is a public web server developed by a small group of programmers. A public domain license refers to any program that is not protected by copyright. Public domain software is free and can be used without restrictions. The term public domain is often mistakenly associated with freeware, which is free software but still protected by copyright. The first version of Apache, based on the NCSA httpd web server, was developed in 1995. Because Apache was developed from existing NCSA code with various fixes, it was called a patchy server, hence the name Apache Server.
As a result of its sophisticated features, excellent performance, and low price (it is free), Apache has become the most popular web server in the world. According to Netcraft (http://news.netcraft.com), it is used to host more than 60% of all websites worldwide.
The core development of the Apache Web Server is carried out by a group of about 20 volunteer programmers, known as the "Apache Group." However, since the source code is freely available, anyone can adapt the server for specific needs, and there is a large public library of add-ons for Apache. An "add-on" refers to a product that complements another product. In many ways, the development of Apache is similar to the development of the Linux operating system.
The original version of Apache was written on UNIX, but there are now versions that run on OS/2, Windows, and other platforms.
Apache has proven to be more robust, more stable, and more feature-rich than other web servers. Although some commercial servers have claimed to surpass Apache in speed.
Apache runs on more than 6 million servers on the Internet (as of February 2000). It has been thoroughly tested by both developers and users. The Apache group maintains strict standards before releasing new versions of their server, and when bugs appear, the developers release fixes for new versions as soon as they are available.
Who would have believed that a small freeware web server could stand up to the combined attack of Netscape and Microsoft? Well, the Apache project is doing quite well. By most accounts, Apache remains the No. 1 HTTP server on the web. In fact, according to Netcraft, Apache currently hosts more websites than Microsoft servers by tens of percent.
This is quite an achievement, considering that the Apache Group is not even a corporation. Instead, it is a group of contributors who propose and approve changes to the code by voting.
The Apache Group and the free Apache HTTP Server stand as a throwback to the less commercial early days of the web, when it seemed that things should be done for love, not for money. Open standards supported and maintained by the people who use them is still a good thing for the internet.
The Apache httpd server is a powerful, flexible HTTP/1.1-compliant server. It implements the latest protocols, including HTTP/1.1 (RFC2616), and is very easy to configure and extend with third-party modules. It can be customized by writing "modules" using the Apache API module, provides full source code, and comes with an unrestrictive license. It runs on Windows NT/9x, Netware 5.x and above, OS/2, and most versions of Unix, as well as several other operating systems. It is actively developed and encourages user feedback through new ideas, bug reports, and patches. It implements many features requested by users, including:
DBM databases for authentication
This allows you to easily set up password-protected pages with a huge number of authorized users, which does not overload the server.
Customized responses to errors and problems
Allows you to configure files, or even CGI scripts, which are returned by the server in response to errors and problems, for example installing a script to intercept 500 server errors and perform real-time diagnostics for both visitors and yourself.
Multiple Directory Index Directives
Allows you to say Directory Index index.cgi index.html, which instructs the server to either send back index.cgi index.html or run when a URL in the directory is requested, whatever it finds in the directory. Flexible URL rewriting aliasing.
Apache has no fixed limit on the number of aliases and redirects that may be found in configuration files. In addition, a powerful rewrite engine can be used to solve most URL manipulation problems.
Content Negotiation
This is the ability to automatically serve clients of different sophistication and HTML compatibility levels with documents that offer the best representation of information that the client is capable of receiving.
Virtual Hosts
A much-requested feature, sometimes referred to as multi-homed servers. This server allows you to distinguish between different requests made to IP addresses or names (mapped to the same machine). Apache also offers dynamic configuration of virtual hosts.
Reliable configuration Tweet logs
You can configure Apache to create logs in the desired format. In addition, on most Unix architectures, Apache can send log files to a pipe, which allows log rotation, hit filtering, real-time splitting of multiple vhosts into separate logs, and asynchronous DNS resolution on the fly.
Your first steps into the Apache world are much easier than you might think. If you are a regular Unix user, you will be well prepared to set up Apache. And the Windows version installs just like any other Windows application.
The first step is to obtain a copy of Apache. Since it's free, there's no reason not to try it. The download files are 2.7MB for the Windows version and just over 1MB for the Unix version. Yes, it's possible to write lean, high-end applications.