Using WPAD

WPAD allows Internet Explorer to automatically detect a server that can supply it with proxy server configuration settings. Clients do not have to configure their browsers to send requests to a proxy server: a single server provides the settings to all clients on the network.

Note: WPAD is incompatible with transparent proxy deployments.

When an Internet Explorer browser starts up, it searches for a WPAD server. It prepends the hostname WPAD to the current fully qualified domain name. For example, a client in x.y.company.com searches for a WPAD server at wpad.x.y.company.com. If unsuccessful, the browser removes the bottommost domain and tries again; for example, it tries wpad.y.company.com. The browser stops searching when it detects a WPAD server or reaches the third-level domain, wpad.company.com. The algorithm stops at the third level so that the browser does not search outside the current network.

Note: By default, Microsoft Internet Explorer are set to automatically detect WPAD servers. However, browser users can disable this setting.