The Web Proxy Auto-Discovery Protocol (WPAD) is a method used by clients to locate a URL of a configuration file using DHCP and/or DNS discovery methods. Once detection and download of the configuration file is complete it can be executed to determine the proxy for a specified URL. The WPAD protocol only outlines the mechanism for discovering the location of this file, but the most commonly deployed configuration file format is the Proxy auto-config format originally designed by Netscape in 1996 for Netscape Navigator 2.0.^[1] The WPAD protocol was drafted by a consortium of companies including Inktomi Corporation, Microsoft Corporation, RealNetworks, Inc., and Sun Microsystems, Inc.. WPAD is documented in an INTERNET-DRAFT which expired in December 1999.^[2] However WPAD is still supported by all major browsers.^[3][4] WPAD was first included with Internet Explorer 5.0.

via Web Proxy Autodiscovery Protocol – Wikipedia, the free encyclopedia.