Windows Authentication for Websites Windows Authentication on IIS works using the Physical Path' Permissions, configured in the  Basic Settings  of the Site. How to Configure This applies both for new and existing Sites Start the IIS Manager Application (Server Manager -> Tools ->  Internet Information Services (IIS) Manager ) Open or create your Site The  Physical Path  Setting here is what counts. If you intend to use it as Reverse Proxy, create a empty "dummy" Directoy for this one Select your Directory If you already have a site, go to  Actions  ->  Basic Settings  and update your Physical Path if necessary Go to Actions -> Edit Permissions This will open the Windows Directory Permissions Dialog. Here you can set your Permission. For Web Access, the Read Permission is required. Dependening on your Use-Case, other Permissions such as Write and Execute might be necessary