A Web server is
|“||[a] computer that provides World Wide Web (WWW) services on the Internet. It includes the hardware, operating system, Web server software, and Web site content (Web pages). If the Web server is used internally and not by the public, it may be known as an "intranet server."||”|
The delivered content may contain text, image, audio, and video information, formatted in HTML or another markup language. A Web server performs this function by responding to HTTP requests sent to it from a Web browser.
How a Web server works
The transaction begins when a browser requests a resource from the Web server. In the simplest case, the Web server retrieves the requested content from a file system and transmits it to the browser. While this approach works well for static, non-volatile information, it can be unsuitable in situations where the information is volatile, already resides in a database or other repository under a different format, or varies according to the input provided. In such cases, the Web server responds to the request by creating the content dynamically, typically by spawning a process or lightweight thread to generate the information. The Common Gateway Interface (CGI) is an industry standard for communicating between a Web server and another program that is often employed in such instances.
- NIST Special Publication 800-45, Glossary, at A-3.