Recently tried to get a new MVC 4 application running on IIS7 and ran into an issue that required a hotfix. The IIS7 server was 2008 SP2 fully patched and had both .NET 2.0 and .NET 4.5 installed, however, whenever I attempted to load the application, IIS would return a 403.14 error message about a directory listing being denied.
Many solutions suggested that ASP.NET wasn’t registered properly, and I confirmed that my application pool settings were correct (need to run Integrated Mode or configure asp.net to handle all traffic so requests are routed to the controllers). Others recommended code solutions, but Sean Anderson’s solution on this stackoverflow.com post was the resolution for me.
There’s an extensionless URL hotfix (I blogged about this hotfix in relation to 404 errors) for IIS7 that is required: http://support.microsoft.com/kb/980368.