I am getting 403 Directory Listing Denied for the root and 404 for an action that I know should exist. Background: I have build and deployed an ASP.NET MVC 2 applcation a long time ago. Later I upgraded it to MVC 3 and it is still working with not configuration changes. Setting it up on a windows 2003 R2 (Standard) initialy was a pain, but after a couple of days(yes, days) struggling it started working. Now I have to do the same with the same application on a different server (2003 R2 Standard again) on a different network. .Net 4 is installed and allowed ASP.NET MVC 3 is also installed By default IIS is set to use .net 4 I verify aspnet_isapi.dll used in application extension are from version 4.0.30319 .NET asemblies folder. I also added the wildcard mapping to aspnet_isapi.dll and unchecked verify file exists. Under Directory Security in Authentication Methods I have disabled anonymos access and enabled Integrated Windows authentication(same as the one on the server that it works) I have copied the same web.config with the <authentication mode="Windows" /> <authorization> <deny users="?" /> </authorization> I have set Read & Execute, List Folder Contents, and Read for the Networkservice account(under which the app pool is working). Also I have set the same for Network account, IIS_WPG, ASPNET and IUSR_MAchineName. I do not have an EnableExte??nsionlessUrls but even if I create it and set it to true or false it does not help. I also tried http://haacked.com/archive/2010/12/22/asp-net-mvc-3-extensionless-urls-on-iis-6.aspx and it did not help. But I kept getting 403 Directory Listing Denied for the root and 404 for an action that I know should exist. Web Platform installer was then used to re-install and possibly update .net, asp.net etc. I then noticed IIS was reset to default. So I added the wildcard mapping again. No, luck still 403. I exported configuration files from the working server setup and created new default app pool and new default website using those configurations. Still I get 403 Directory Listing Denied for the / and 404 for any action I try.