Apache Server

The Apache HTTP Server, plays a key role in the initial growth of the World Wide Web. In 2009 it became the first web server software to surpass the 100 million website mileston.. Typically Apache is run on a Unix-like operating system.

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

The application is available for a wide variety of operating systems, including Unix, FreeBSD, Linux, Solaris, Novell NetWare, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released under the Apache License, Apache is open-source software.
Since April 1996 Apache has been the most popular HTTP server software in use. As of March 2012 Apache was estimated to serve 57.46% of all active websites and 65.24% of the top servers across all domains.

Apache supports a variety of features.These can range from server-side programming language support to authentication schemes. Some common language interfaces support
• Perl
•  Python
•  Tcl
•  PHP

A sample of other features include
• Secure Sockets Layer
•  Transport Layer Security support (mod_ssl)
•  proxy module (mod_proxy)
• URL rewriter (also known as a rewrite engine),
Virtual hosting allows one Apache installation to serve many different actual websites. 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. Apache has a built in search engine and an HTML authorizing tool and supports FTP.