The Apache Web Server
The Apache web server, original name Apache HTTP Server is the most used web server on the World Wide Web.
The web server is created by the Apache Software Foundation. The system is freely distributed under an open source license.
The first version was released in 1995. The current version number is 2.4.25 (status 12/2016).
History of development
In 1994, eight developers decided to improve the NSCA Httpd web server. The team, consisting of David Robinson, Cliff Skolnick, Randy Terbush, Roy T. Fielding, Rob Hartill, Brian Behlendorf, Robert S. Thau, and Andrew Wilson, patched extensions to the old NSCA server and released the first version of the Apache HTTP Server in 1995. The name was chosen out of respect for the Indian tribe of Apatschen. Today the developer community consists mainly of volunteer developers around the world. The Apache web server is the product of suggestions and ideas for improvement from all users worldwide. Because of the open source code, every interested and qualified user can program his improvements directly into the Apache web server.
System properties
The modular web server supports a variety of operating systems, including Linux, Unix and Windows. The stability and speed of the server was significantly improved in version 2.0, primarily for non-Unix systems.
Important system functions are generalized and made available via the Apache library Portable Runtime, so that the special features of the different operating systems can be fully utilized. Depending on the platform, the various MPM (Multiprocessing) modules are also different. Among other things, these modules are used to process multiple client requests. These MPM's are each optimized for the operating system, so that under Windows the MPM is optimized for threads, while under Unix the forking of processes is supported.
Due to its modular structure, the Apache web server can, by means of appropriate modules, for example, act as a proxy server (mod_proxy), encrypt the communication between the Internet browser and the web server (mod_ssl) or manipulate the HTTP headers. Modifications to URL data are also possible.
With the help of server-side scripting languages like Perl, Ruby or PHP the Apache HTTP Server offers the possibility to create dynamic web pages. These scripting languages, which include JavaScriptPython and .Net must be included as modules or accessed via CGI. It is possible to activate or deactivate different modules at any time.
By means of the mod_include of the Apache HTTP Server, Server Side Includes are possible which considerably reduce the administration effort of static websites by creating dynamic websites.
Like all programs of the Apache Software Foundation, the Apache HTTP Server is free software. The licensing is done according to the GPL standards.
Extensibility
Apache Web server offer very good expandability due to their modular design. These modules, which are freely available everywhere on the Internet, always start with "mod_". They can be downloaded and integrated into the web server according to the intended use. There is a large number of modules available. Purpose of use are among others security functions (e.g. SSL), the integration of script languages, redirections, authentication, status reports and much more.
Platforms and versions
The Apache HTTP Server is included by default in both Mac Os and all Linux distributions. Windows is also fully supported by the software.
The 1.x version series, the first version of which was released in 1995, expired with version 1.3.x in February 2010. Since March 2000, the development of the 2.x version series has been running in parallel. From this series, only version 2.2.x is supported in addition to the current version 2.4.x and is supplied with security updates.
