The Apache HTTP Server, commonly referred to as Apache , is snare server software matchless seeking playing a key role in the commencing growth of the World Big Web. In 2009 it became the ahead web server software to pass beyond the 100 million website milestone. Apache was the chief viable different to the Netscape Communications Corporation trap server (currently known as Seer iPlanet Web Server), and has since evolved to rival other trap servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained not later than an open community of developers second to the protection of the Apache Software Foundation. The operation is elbow instead of a deviating multiplicity of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released impaired the Apache Commission, Apache is open-source software.
Since April 1996 Apache has been the most fashionable HTTP server software in use. As of May 2011 Apache was estimated to serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a variety of features, varied implemented as compiled modules which augment the gist functionality. These can range from server-side programming language stick up for to authentication schemes. Some common lingua franca interfaces guy Perl, Python, Tcl, and PHP. Popular authentication modules comprehend mod_access, mod_auth, mod_pr‚cis, and mod_auth_r‚sum‚, the successor to mod_digest. A example of other features classify SSL and TLS supporter (mod_ssl), a factor module (mod_proxy), a URL rewriter (also known as a rewrite locomotive, implemented lower than drunk mod_rewrite), routine log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_cheesecloth).
Sought-after compression methods on Apache take in the superficial dimensions module, mod_gzip, implemented to servants with reduction of the appraise (weight) of entanglement pages served over HTTP. ModSecurity is an open fountain-head intrusion detection and enjoining apparatus in the direction of web applications. Apache logs can be analyzed from one end to the other a entanglement browser using delivered scripts such as AWStats/W3Perl or Visitors.
Effective hosting allows song Apache station to fulfil many unalike actual websites. Through despite model, joined gizmo with joined Apache installation could simultaneously serve www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and content negotiation. It is also supported near sundry graphical drug interfaces (GUIs).
It supports password authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing dupe and supports FTP.

Performance


This portion does not cite any references or sources. Content help repair this fraction nearby adding citations to reliable sources. Unsourced figures may be challenged and removed. (October 2009)
Although the sheer develop aspiration of Apache is not to be the "fastest" spider's web server, Apache does have dispatch comparable to other "high-performance" network servers. As contrasted with of implementing a only architecture, Apache provides a breed of MultiProcessing Modules (MPMs) which deduct Apache to hump it in a process-based, hybrid (function and thread) or event-hybrid look, to superior meet the demands of each thorough infrastructure. This implies that the choice of suitable MPM and the correct configuration is important. Where compromises in doing desperate straits to be made, the design of Apache is to humble latency and augment throughput, associated to simply handling more requests, in which case ensuring predictable and honourable processing of requests within logical time-frames.
The Apache version considered by the Apache Fundamental as providing high-performance is the multi-threaded translation which mixes the manipulate of a handful processes and several threads per process.
While this architecture works faster than the previous multi-process based topology (because threads suffer with a lower overhead than processes), it does not copy the performances of the event-based architecture provided by other servers, uncommonly when they prepare events with a variety of wage-earner threads.
This dissimilarity can be without even trying explained by means of the overhead that a man line per union brings (as opposed to a four of breadwinner threads per CPU, each processing many correlation events). Each squeeze through needs to contend its own clamp, environs, and switching from inseparable plot to another is also an valuable stint in search CPUs.