<World-Wide Web> A proxy server for HTTP requests. Typically an HTTP proxy or "web proxy" accepts HTTP requests containing URLs with a special prefix. The proxy removes the prefix and looks for the resulting URL in its local cache (if it is a caching proxy). If found, it returns the document immediately, otherwise it fetches it from the remote server, saves a copy in its cache and returns it to the requester. The cache will usually have an expiry algorithm which flushes documents according to their age, size and access history. The purpose is to reduce the amount of data flowing over the proxy's Internet connection and to speed up clients' access to frequently requested pages, e.g. at an ISP or on a large company's firewall. The proxy may also reject requests where the URL or content matches certain conditions. The Apache HTTP server can be configured to act as a proxy server. Another popular software proxy is Squid. (2008-07-01)

<software, security> (Capitalised) Microsoft's {proxy server} and proxy gateway, designed to provide extensible firewall and network security. Proxy Server is part of BackOffice. (1999-09-17)

HTTP proxy server

In computer networking, a proxy server is a server application that acts as an intermediary between a client requesting a resource and the server providing that resource.World-Wide Web Proxies, Ari Luotonen, April 1994

proxy server

<networking> A server process that intercepts requests from a client, passes them to an origin server and returns the response to the client while performing various other operations in the process. An HTTP proxy server is a common example. A proxy may be used for purposes of security, performance (caching) or anonymity. It may be purely software or may run on its own hardware, either a standard PC or server machine or a custom hardware appliance. A software proxy may be on the same computer as the client or the origin server, separate hardware may be anywhere on the network in between. The proxy may filter requests, rejecting some if the request or response matches certain conditions (e.g. an antivirus proxy). It may cache requests and responses to reduce load on the origin server or data volume on the network or to provide quicker response to the client for common requests. The proxy may modify the request or response, e.g. to convert between different protocols or interfaces. Proxy servers are often used in large companies as part of a firewall so that users within the company need have no direct connection to the Internet (and can use a {private IP address} range) but can still access the World-Wide Web, instant messenger, etc via the proxy. Usually this requires each client to be configured to use the proxy. The term "proxy gateway" may more imply transparency (less intervention) in the request-response process, though is often used as a synonym for proxy server. (2008-07-01)

HTTP server

A web server is computer software and underlying hardware that accepts requests via HTTP (the network protocol created to distribute web content) or its secure variant HTTPS. A user agent, commonly a web browser or web crawler, initiates communication by making a request for a web page or other resource using HTTP, and the server responds with the content of that resource or an error message.

The Apache HTTP Server ( ə-PATCH-ee) is a free and open-source cross-platform web server software, released under the terms of Apache License 2.0. Apache is developed and maintained by an open community of developers under the auspices of the Apache Software Foundation.

The vast majority of Apache HTTP Server instances run on a Linux distribution, but current versions also run on Microsoft Windows, OpenVMS, and a wide variety of Unix-like systems. Past versions also ran on NetWare, OS/2 and other operating systems, including ports to mainframes.

Originally based on the NCSA HTTPd server, development of Apache began in early 1995 after work on the NCSA code stalled. Apache played a key role in the initial growth of the World Wide Web, quickly overtaking NCSA HTTPd as the dominant HTTP server. In 2009, it became the first web server software to serve more than 100 million websites.

As of March 2022, Netcraft estimated that Apache served 23.04% of the million busiest websites, while Nginx served 22.01%. Cloudflare at 19.53% and Microsoft Internet Information Services at 5.78% rounded out the top four. For some of Netcraft's other stats Nginx is ahead of Apache. According to W3Techs review of all web sites in June 2022 Apache was ranked second at 31.4% and Nginx first at 33.6%, with Cloudflare Server third at 21.6%.