Apache HTTP Server

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Apache HTTP Server is a free software/open source web server for Unix-like systems, Microsoft Windows, Novell NetWare and other platforms. Apache is notable for playing a key role in the initial growth of the World Wide Web, and continues to be the most popular web server in use,http://news.netcraft.com/archives/web_server_survey.html serving as the de facto reference platform against which other web servers are designed and judged.

Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported by several graphical user interfaces (GUIs) which permit easier, more intuitive configuration of the server.

Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

Contents

1 History
2 License
3 Usage
4 Features
5 Apache 2
6 See also
7 References
8 External links

History

The first version of the Apache web server was created by Rob McCool, who was heavily involved with the National Center for Supercomputing Applications web server, known simply as NCSA HTTPd. When Rob left NCSA in mid-1994, the development of httpd stalled, leaving a variety of patches for improvements circulating through e-mails.

Rob McCool was not alone in his efforts. Several other developers helped form the original "Apache Group": Brian Behlendorf, Roy T. Fielding, Rob Hartill, David Robinson, Cliff Skolnick, Randy Terbush, Robert S. Thau, Andrew Wilson, Eric Hagberg, Frank Peters, and Nicolas Pioch.

The FAQ on the project's official site states: "The name 'Apache' was chosen from respect for the Native American Indian tribe of Apache (Indé), well-known for their superior skills in warfare strategy and their inexhaustible endurance." However, the most widespread interpretation is that the name comes from the fact that when it was developed in early 1995, the web server consisted a set of patches to the codebase of NCSA HTTPd 1.3 and was therefore "a patchy" server. This was the explanation initially given on the project's website.[Wayback Machine link to the Apache website, 1997]

When first released, Apache was the only viable open source alternative to the Netscape web server (currently known as Sun Java System Web Server). It has since evolved to rival other Unix-based web servers in terms of functionality and performance. Since April 1996 Apache has been the most popular HTTP server on the Internet. By May 1999 Apache installations served 57% of all websites. Its popularity continued to rise, and in February 2006 Apache served 68% of all websites.[Netcraft Web Server Survey, February 2006] Microsoft's Internet Information Services (IIS) is the main competitor to Apache, trailed by Sun Microsystems' Sun Java Web Server and a host of other applications such as Zeus.

License

The License under which software from the Apache Foundation is distributed is a distinctive part of the Apache HTTP Server's history and presence in the open source software environment. The Apache License allows for the distribution of both open- and closed-source derivations of the source code.

Furthermore, it is perhaps surprising that the Free Software Foundation does not consider the Apache License to be "compatible" with version 2.0 of the GNU General Public License (GPL), meaning that software licensed under the Apache License cannot be integrated with software that is distributed under the GPL. Here is what the FSF says about the Apache License:

The current draft of Version 3 of the GPL includes a provision (Section 7e) which allows it to be compatible with licenses that have patent retaliation clauses, including the Apache License.

Usage

Apache is primarily used to serve static and dynamic content on the World Wide Web. Many web applications are designed expecting the environment and features that Apache provides.

Apache is the web server component of the popular LAMP web server application stack, alongside Linux, MySQL, and the PHP/Perl/Python programming languages.

Apache is redistributed as part of various proprietary packages, such as the Oracle database or the IBM WebSphere application server. Mac OS X integrates Apache as its built-in web server. It is also supported in some way by Borland in the Kylix and Delphi development tools. Apache is included with Novell Netware 6.5, where it is the default web server.

Apache is used for many other tasks where content needs to be made available in a secure and reliable way. One example is sharing files from a personal computer over the Internet. A user who has Apache installed on their desktop can put arbitrary files in the Apache's document root which can then be shared.

Programmers developing web applications often use a locally installed version of Apache in order to preview and test code as it is being developed.

Features

Apache supports a variety of features, many implemented as compiled modules which extend the core functionality. These can range from server-side programming language support to authentication schemes. Some common language interfaces support Perl, Python, Tcl, and PHP. Popular authentication modules include mod_access, mod_auth, and mod_digest. A sample of other features include SSL and TLS support (mod_ssl), a proxy module, a useful URL rewriter (also known as a rewrite engine, implemented under mod_rewrite), custom log files (mod_log_config), and filtering support (mod_include and mod_ext_filter). Apache logs can be analyzed through a web browser using free scripts such as AWStats or Visitors.

Apache 2

Version 2 of the Apache server was a substantial re-write of much of the code, with a strong focus on further modularisation and the development of a portability layer; the APR. The Apache 2.x core has several major enhancements over Apache 1.x. These include UNIX threading, better support for non-Unix platforms (such as Windows), a new Apache API, and IPv6 support. The first alpha release of Apache 2 was in March 2000 with the first general availability release in May 2002.

Version 2.2 introduced a new auth API that allows for more flexibility. It also features improved cache modules and proxy modules.

References

This article was originally based on material from the Free On-line Dictionary of Computing, which is [Foldoc licenselicensed] under the GFDL.

External links

Apache

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