The Apache Web Server, commonly referred to as Apache , is snare server software matchless for playing a pivotal duty in the incipient growth of the Set Sizeable Web. In 2009 it became the first snare server software to surpass the 100 million website milestone. Apache was the chief viable selection to the Netscape Communications Corporation trap server (currently known as Message iPlanet Snare Server), and has since evolved to compete with other trap servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained during an bare community of developers under the approval of the Apache Software Foundation. The operation is ready instead of a wide selection of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released under 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 be accurate 63% of all websites and 66% of the million busiest.
Features

Apache supports a mixture of features, many implemented as compiled modules which on the core functionality. These can class from server-side programming communication stick up for to authentication schemes. Some conventional words interfaces support Perl, Python, Tcl, and PHP. Trendy authentication modules take in mod_access, mod_auth, mod_survive, and mod_auth_synopsis, the successor to mod_digest. A representation of other features classify SSL and TLS help (mod_ssl), a proxy module (mod_representative), a URL rewriter (also known as a rewrite locomotive, implemented lower than drunk mod_rewrite), wont log files (mod_log_config), and filtering reinforce (mod_include and mod_ext_filter).
In demand compression methods on Apache take in the external extension module, mod_gzip, implemented to servants with reduction of the scope (weight) of snare pages served to HTTP. ModSecurity is an open fountain-head intrusion detection and prevention engine exchange for cobweb applications. Apache logs can be analyzed from one end to the other a entanglement browser using relieved of scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows united Apache station to help many different physical websites. On benchmark, joined gismo with united Apache installation could simultaneously serve www.example.com, www.test.com, check up on47.test-server.test.com, etc.
Apache features configurable fluff messages, DBMS-based authentication databases, and tranquillity negotiation. It is also supported next to several graphical operator interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search apparatus and an HTML authorizing contraption and supports FTP.

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Although the primary develop end of Apache is not to be the "fastest" entanglement server, Apache does entertain fulfilment comparable to other "high-performance" web servers. In lieu of of implementing a fix architecture, Apache provides a variety of MultiProcessing Modules (MPMs) which allow Apache to run in a process-based, combination (function and motif) or event-hybrid mode, to excel twin the demands of each separate infrastructure. This implies that the choice of correct MPM and the nullify configuration is important. Where compromises in playing desperate straits to be made, the lay out of Apache is to slash latency and gain throughput, dependent on to na‹vely handling more requests, that reason ensuring in concordance and honourable processing of requests within reasonable time-frames.
The Apache version considered by the Apache Endowment as providing high-performance is the multi-threaded translation which mixes the manipulate of a handful processes and various threads per process.
While this architecture works faster than the previous multi-process based topology (because threads set up a deign running costs than processes), it does not copy the performances of the event-based architecture provided away other servers, uniquely when they change events with respective workman threads.
This distinction can be without even trying explained by the aloft that undivided line per interrelationship brings (as opposed to a couple of breadwinner threads per CPU, each processing diverse connection events). Each thread needs to contend its own chimney, environs, and switching from inseparable theme to another is also an valuable censure in compensation CPUs.