How does Windows actually detect LAN (proxy) settings when using Automatic Configuration

Question

When Windows Internet Properties -> Connections -> LAN Settings -> Automatic Configuration is set to \"Automatically detect settings\" how does Windows actually determine/di

Answer 1

Its simple: Browsers (Firefox works the same) query GET http://wpad/wpad.dat.

If a web server named wpad is resolveable, it should serve wpad.dat, a script file analog to netscape PAC files. MIME type must also be "application/x-ns-proxy-autoconfig".