IIS URL Rewriting and ASP.NET routing

With the release of URL-rewrite module for IIS 7.0 and the inclusion of ASP.NET routing into the .NET Framework 3.5 SP1, there have been a lot of questions from ASP.NET developers about how these two features relate to each other and when to use each.

Differences between URL Rewriting and ASP.NET Routing

Based on the above explanation you can see that the main conceptual differences between URL rewriting and ASP.NET routing are the following:

  1. URL rewriting is used to manipulate URL paths before the request is handled by the Web server. The URL-rewriting module does not know anything about what handler will eventually process the rewritten URL. In addition, the actual request handler might not know that the URL has been rewritten.
  2. ASP.NET routing is used to dispatch a request to a handler based on the requested URL path. As opposed to URL rewriting, the routing component knows about handlers and selects the handler that should generate a response for the requested URL. You can think of ASP.NET routing as an advanced handler-mapping mechanism.

In addition to these conceptual differences, there are the following functional differences between IIS URL rewriting and ASP.NET routing:

  1. The IIS URL-rewrite module can be used with any type of Web application, which includes ASP.NET, PHP, ASP, and static files. ASP.NET routing can be used only with .NET Framework-based Web applications.
  2. The IIS URL-rewrite module works the same way regardless of whether integrated or classic IIS pipeline mode is used for the application pool. For ASP.NET routing, it is preferable to use integrated pipeline mode. ASP.NET routing can work in classic mode, but in that case the application URLs must include file extensions or the application must be configured to use "*" handler mapping in IIS.
  3. The URL-rewrite module can make rewriting decisions based on domain names, HTTP headers, and server variables. By default, ASP.NET routing works only with URL paths and with the HTTP-Method header.
  4. In addition to rewriting, the URL-rewrite module can perform HTTP redirection, issue custom status codes, and abort requests. ASP.NET routing does not perform those tasks.
  5. The URL-rewrite module is not extensible in its current version. ASP.NET routing is fully extensible and customizable.

Which Option Should You Use? Read more @ IIS URL Rewriting and ASP.NET routing : Using URL Rewrite Module : Installing and Configuring IIS 7.0 : The Official Microsoft IIS Site

IIS UR Rewriting

ASP.NET Routing