Web server

A web server is a server which is specifically built for the Hyper-Text Transfer Protocol (HTTP). On the internet, an intranet, or on a local environment, a web server continually waits for stateless requests and responds appropriately.

Typically HTTP requests are handled on port 80 and HTTPS on port 443.

Clients

Any software using the HTTP protocol and connecting to the correct port can communicate with a web server. End users typically communicate with a web server using a graphical or text-based web browser.

Other systems communicate with web servers for a variety of reasons, including:

• Search engine indexing
• Caching
• Payment processing
• XML-RPC - requesting data or performing actions using XML

See also: Client-server

Implementation

Modern general purpose web servers are often built in a modular fashion. The core listens to requests and delegates actions to loaded modules. These modules may implement simple file handlers, security protocols, scripting engines, etc. This lets one web server handle many different types of requests and for web applications to be built with various programming languages and configurations.

Other web server implementations can be optimized for specific scenarios. For example, a web server may be just a thin layer that sends all requests to one scripting engine. Or it may interface to another server that serves multiple applications.

Web Server Implementations

• Apache httpd
• Microsoft IIS