Getting 404.0 error for ASP.NET MVC 3 app on IIS 7.0 / Windows Server 2008

.net-4.0asp.net-4.0asp.net-mvc-3iis-7windows-server-2008

I am attempting to deploy an ASP.NET MVC 3 application to a Windows 2008 x64 server (running IIS 7.0 obviously), and IIS does not want to seem to serve up the content properly. All requests are resulting in a 404.0 error, because the requests are not matching any handler and IIS is attempting to use the StaticFile handler to serve up the requests. The issue seems to be related to .NET 4.0, as I have an MVC 2 application running just fine in an app pool that is configured for the .NET 2.0 runtime.

I have had no issues deploying this same application to IIS 7.5 servers both on Windows 7 and Windows Server 2008 R2.

Prior to deployment, the 2008 server did not have .NET 4.0 or ASP.NET MVC 3 installed, so here are the steps I undertook prior to deploying the application:

  1. Installed .NET 4.0
  2. Ran aspnet_regiis.exe (from the Framework64/v4.0.30319 folder)
  3. Installed ASP.NET MVC 3 using the web platform installer
  4. Applied MS update KB980368 to enable certain IIS 7.0 or IIS 7.5 handlers to handle requests whose URLs do not end with a period

Requests to static resources in the application (JavaScript files, images, etc) go through without a hitch, but any request to an MVC action fails with a 404.0 error. I have noticed that IIS is using the StaticFile handler to handle these requests, which is obviously incorrect. The ASP.NET 4.0 handlers (i.e. ExtensionlessUrl-ISAPI-4.0* handlers) are properly defined as far as I can tell, so I have no idea why/how the request would not be handled by one of these handlers and would fall all the way down to the StaticFile handler.

I also came across the following MS knowledge base article which mentions that you should ensure HTTP Redirection and Static Content Compression are enabled/installed on the server where you are experiencing the 404 errors. I checked, and both features were already enabled for my server. I even tried removing and reinstalling the features to no avail.

At this point I am completely out of ideas for why this is not working properly. I have been able to replicate the issue on 2 different IIS 7.0 servers. What am I missing?

Best Answer

You actually just reminded me that I needed to fix this issue in an enviroment here. If your situation is the same as mine then it's a simple fix.

Just add the following to your web config:

<system.webServer>
    <modules runAllManagedModulesForAllRequests="true" />

Edit: To provide further explanation on the issue at hand. In my case what was happening was when I added custom route mappings IIS was seeing the requests as Folder/Static File requests and thus was skipping over the ASP.NET worker process. This behaves differently under development environment generally because it is being run under the development web server which will also pass all requests through the .net process.

This Web Config entry tells IIS that you have modules that should be run on every web request even if IIS determines it to be a static file or a folder.

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