Apache HTTP Server

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Apache HTTP Server
Original author(s) Robert McCool
Developer(s) Apache Software Foundation
Initial release 1995 (1995)[1]
Stable release 2.4.12 (January 29, 2015; 61 days ago (2015-01-29)) [±]
Development status Active
Written in C/C++,[2] XML[3]
Operating system Cross-platform
Type Web server
License Apache License 2.0
Website httpd.apache.org

The Apache HTTP Server, colloquially called Apache (/əˈpæ/ ə-PA-chee), is the world's most widely used web server software. Originally based on the NCSA HTTPd server, development of Apache began in early 1995 after work on the NCSA code stalled. Apache played a key role in the initial growth of the World Wide Web,[4] quickly overtaking NCSA HTTPd as the dominant HTTP server, and has remained the most popular HTTP server since April 1996. In 2009, it became the first web server software to serve more than 100 million websites.[5]

Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation. Most commonly used on a Unix-like system (usually Linux),[6] the software is available for a wide variety of operating systems, including Unix, FreeBSD, Linux, Solaris, Novell NetWare, OS X, Microsoft Windows, OS/2, TPF, OpenVMS and eComStation. Released under the Apache License, Apache is free and open-source software.

As of June 2013, Apache was estimated to serve 54.2% of all active Web sites and 53.3% of the top servers across all domains.[7][8][9][10][11]


According to the FAQ in the Apache project website, the name Apache was chosen out of respect to the Native American tribe Apache and its superior skills in warfare and strategy. The name was widely believed to be a pun on A Patchy Server (since it was a set of software patches), but this is erroneous.[12] Official documentation used to give this very explanation of the name,[13] but in a 2000 interview, Brian Behlendorf, one of the creators of Apache, set the record straight:[14]

The name literally came out of the blue. I wish I could say that it was something fantastic, but it was out of the blue. I put it on a page and then a few months later when this project started, I pointed people to this page and said: "Hey, what do you think of that idea?" ... Someone said they liked the name and that it was a really good pun. And I was like, "A pun? What do you mean?" He said, "Well, we're building a server out of a bunch of software patches, right? So it's a patchy Web server." I went, "Oh, all right." ... When I thought of the name, no. It just sort of connotated: "Take no prisoners. Be kind of aggressive and kick some ass."

When Apache is running, its process name is sometimes httpd, which is short for "HTTP daemon."


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, mod_digest, and mod_auth_digest, the successor to mod_digest. A sample of other features include Secure Sockets Layer and Transport Layer Security support (mod_ssl), a proxy module (mod_proxy), a URL rewriter (mod_rewrite), custom log files (mod_log_config), and filtering support (mod_include and mod_ext_filter).

Popular compression methods on Apache include the external extension module, mod_gzip, implemented to help with reduction of the size (weight) of Web pages served over HTTP. ModSecurity is an open source intrusion detection and prevention engine for Web applications. Apache logs can be analyzed through a Web browser using free scripts, such as AWStats/W3Perl or Visitors.

Virtual hosting allows one Apache installation to serve many different Web sites. For example, one machine with one Apache installation could simultaneously serve www.example.com, www.example.org, test47.test-server.example.edu, etc.

Apache features configurable error messages, DBMS-based authentication databases, and content negotiation. It is also supported by several graphical user interfaces (GUIs).

It supports password authentication and digital certificate authentication. Because the source code is freely available, anyone can adapt the server for specific needs, and there is a large public library of Apache add-ons.[15]


Instead of implementing a single architecture, Apache provides a variety of MultiProcessing Modules (MPMs), which allow Apache to run in a process-based, hybrid (process and thread) or event-hybrid mode, to better match the demands of each particular infrastructure. This implies that the choice of correct MPM and the correct configuration is important. Where compromises in performance need to be made, the design of Apache is to reduce latency and increase throughput, relative to simply handling more requests, thus ensuring consistent and reliable processing of requests within reasonable time-frames.

For delivery of static pages, Apache 2.2 series was considered significantly slower than nginx.[16] To address this issue, the Apache version considered by the Apache Foundation as providing high-performance is the multi-threaded version, which mixes the use of several processes and several threads per process.[17] This architecture, and the way it was implemented in the Apache 2.4 series, provides for performance equivalent or slightly better than event-based web servers, as is claimed by the president of the Apache Foundation, Jim Jagielski.[18] However, some independent benchmarks show that it still is half as fast as nginx.[19][20]


The Apache HTTP Server codebase was relicensed to the Apache 2.0 License (from the previous 1.1 license) in January 2004,[21] and Apache HTTP Server 1.3.31 and 2.0.49 were the first releases using the new license.[22]

The OpenBSD project did not like the change and continued the use of pre-2.0 Apache versions, effectively forking Apache 1.3.x for its purposes.[23][24][25] Later it switched to nginx.[26][27][28]


Version Initial release Latest release
Old version, no longer supported: 1.3 1998-06-06[29] 2010-02-03 (1.3.42)[30]
Old version, no longer supported: 2.0 2002-04-06[31] 2013-07-10 (2.0.65)[32]
Older version, yet still supported: 2.2 2005-12-01[33] 2014-08-03 (2.2.29)[34]
Current stable version: 2.4 2012-02-21[35] 2015-01-29 (2.4.12)[36]
Old version
Older version, still supported
Latest version
Latest preview version
Future release

The Apache HTTP Server Project is a collaborative software development effort aimed at creating a robust, commercial-grade, feature-rich and freely available source code implementation of an HTTP (Web) server. The project is jointly managed by a group of volunteers located around the world, using the Internet and the Web to communicate, plan, and develop the server and its related documentation. This project is part of the Apache Software Foundation. In addition, hundreds of users have contributed ideas, code, and documentation to the project.[37][38][39]

See also[edit]


  1. ^ "About the Apache HTTP Server Project". Apache Software Foundation. Archived from the original on 7 June 2008. Retrieved 2008-06-25. 
  2. ^ Lextrait, Vincent (January 2010). "The Programming Languages Beacon, v10.0". Retrieved 14 March 2010. 
  3. ^ "Languages". Apache HTTP Server. Black Duck Software. Ohloh. Retrieved 2 April 2014. 
  4. ^ Netcraft Market Share for Top Servers Across All Domains August 1995 - today (monthly updated)
  5. ^ "February 2009 Web Server Survey". Netcraft. Archived from the original on 26 February 2009. Retrieved 2009-03-29. 
  6. ^ OS/Linux Distributions using Apache
  7. ^ "June 2013 Web Server Survey". Netcraft. Retrieved 2013-06-12. 
  8. ^ sage of web servers for websites
  9. ^ Information about the Apache Web Server. (n.d.). Web Hosting Services, VPS Servers and Domain Names by NTC Hosting. Retrieved November 12, 2012
  10. ^ Why Apache Has Held its #1 Spot.
  11. ^ Apache Server Definition. (n.d.). Module for hosting (mod_hosting) for Apache 2 servers. Retrieved November 12, 2012
  12. ^ "Why the name 'Apache'?". HTTPd Frequently Asked Questions. 
  13. ^ "Information on the Apache HTTP Server Project". 1997-04-15. 
  14. ^ Apache Power|Linux Magazine
  15. ^ What is Apache Web server? - A Word Definition From the Webopedia Computer Dictionary. (n.d.). Webopedia: Online Computer Dictionary for Computer and Internet Terms and Definitions. Retrieved November 12, 2012
  16. ^ Serving static files: a comparison between Apache, Nginx, Varnish and G-WAN
  17. ^ Apache MPM worker
  18. ^ Apache httpd 2.4
  19. ^ Apache 2.4 Faster Than Nginx?
  20. ^ Performance of Apache 2.4 with the event MPM compared to Nginx
  21. ^ "Apache License, Version 2.0". The Apache Software Foundation. January 2004. Retrieved 2013-05-21. 
  22. ^ Burton, Richard Antony. "FYI: Apache HTTP Server 2.0.49 Released". Newsgroupalt.apache.configuration. 
  23. ^ de Raadt, Theo (18 February 2004). "The new apache license". openbsd-misc (Mailing list). Retrieved 2013-05-21. 
  24. ^ "Copyright Policy". OpenBSD. Retrieved 2013-05-12. 
  25. ^ "apache-httpd-openbsd-1.3.20140502p2 – OpenBSD improved and secured version of Apache 1.3". OpenBSD ports. Retrieved 2014-12-28. 
  26. ^ OpenBSD Upgrade Guide: 5.1 to 5.2
  27. ^ jj, ed. (2014-03-14). "Heads Up: Apache Removed from Base". OpenBSD Journal. 
  28. ^ OpenBSD Upgrade Guide: 5.5 to 5.6
  29. ^ "Announcement: Apache 1.3.0 Released !". 1998-06-06. Retrieved 2015-01-06. 
  30. ^ http://mail-archives.apache.org/mod_mbox/httpd-announce/201002.mbox/%3C20100203000334.GA19021%40infiltrator.stdlib.net%3E
  31. ^ "Official Release: Apache 2.0.35 is now GA". 2002-04-06. Retrieved 2015-01-06. 
  32. ^ http://mail-archives.apache.org/mod_mbox/httpd-announce/201307.mbox/%3C20130710124920.2b8793ed.wrowe%40rowe-clan.net%3E
  33. ^ "Apache HTTP Server 2.2.0 Released". 2005-12-01. Retrieved 2015-01-06. 
  34. ^ http://mail-archives.apache.org/mod_mbox/httpd-announce/201409.mbox/%3C540737D6.5090908%40apache.org%3E
  35. ^ "[ANNOUNCEMENT] Apache HTTP Server 2.4.1 Released". 2012-02-21. Retrieved 2015-01-06. 
  36. ^ http://www.apache.org/dist/httpd/Announcement2.4.html
  37. ^ Netcraft. (n.d.). About the Apache HTTP Server Project - The Apache HTTP Server Project. Welcome! - The Apache HTTP Server Project. Retrieved November 12, 2012
  38. ^ The Apache HTTP Server Open Source Project on Ohloh. (n.d.). Ohloh, the open source network. Retrieved November 12, 2012
  39. ^ Chapter 4. The Apache HTTP Server. (n.d.). Fedora Documentation. Retrieved November 12, 2012

External links[edit]