Professional Microsoft IIS 8

ASP.NET Configuration

Since IIS 7.0, ASP.NET is more tightly integrated into IIS than it was in previous versions of IIS. ASP.NET services can now be used to provide functionality to all content types, including PHP, static files, and Classic ASP pages. IIS can be extended using ASP.NET modules, rather than relying on ISAPI filters and extensions. These ASP.NET modules integrate directly into the server pipeline; thus, they can run at any point in the processing pipeline. Additionally, they can be run in any order with native IIS modules. With the integration of ASP.NET and IIS comes the added benefit of a unified server run time. Many features, including configuration, error handling, and tracing, have been unified into the same interfaces for the two systems.

IIS 6.0 and Previous Architecture

Prior to IIS 7.0, ASP.NET was implemented with the aspnet_isapi.dll. The route an ASP.NET request would take required IIS first to process the request to determine what needed to be done with the request. If it was determined that it was an ASP.NET request, IIS then passed it off to the aspnet_isapi.dll to process the actual request. The .dll would then pass the completed request back to IIS to return the results to the client's web browser. This process worked fine for ASP.NET file types; however, other file types couldn't take advantage of the features offered in the ASP.NET architecture, nor could IIS use these features outside of the period before or after the ASP.NET execution path. ...