Apache

Apache:

It is the most common web server (or HTTP server) software on the Internet. Apache is an open-source application originally created from a series of changes (“patches”) made to a web server written at the National Center for Supercomputing Applications, the same place the Mosaic web browser was created. Apache is designed as a set of modules, enabling administrators to choose which features they wish to use and making it easy to add features to meet specific needs including handling protocols other than the web-standard HTTP.
The Apache HTTP Server, commonly referred to simply as Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web. Apache was the first viable alternative to the Netscape Communications Corporation web server (currently known as Sun Java System Web Server), and has since evolved to rival other Unix-based web servers in terms of functionality and performance.
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 etc. Released under the Apache License, Apache is free software / open source software. Since April 1996 Apache has been the most popular HTTP server on the World wide Web.