ASP.NET MVC 4 and ExtensionlessUrlHandler

Question

I use VS 2012 and created two application:

1. Application#1. MVC 3, NET 4.5

2. Application#2. MVC 4, NET 4.5

If I compare web.config of these applications, I see the app#2 (MVC 4) has the following handlers registered:

1. ExtensionlessUrlHandler-ISAPI-4.0_32bit
2. ExtensionlessUrlHandler-ISAPI-4.0_64bit
3. ExtensionlessUrlHandler-Integrated-4.0

Could anybody please explain how and when they are used?

One more question (optional). If these handlers are required now, where should I put my handlers? Before or after them?

Answer 1

Here is a blog post that may be helpful.

http://blogs.msdn.com/b/tmarq/archive/2010/05/26/how-extensionless-urls-are-handled-by-asp-net-v4.aspx

(which ironically doesn't use an extensionless url)

My understanding is that you will need IIS 7 or greater to benefit from the Integrated mapping and for anything less you will need to use one of the other ISAPI handlers.