Running ASP.NET 1.1 on IIS7

I am a bit surprised when running ASP.NET 1.1 application on IIS7. You don't have to install .Net framework 1.1. I also suspected that if .Net 1.1 comes pre-installed, but my GAC (Global Assembly Cache) have only 2.0 libraries.

Maybe I shouldn’t be surprised, according to IIS team this is because of the backward compatibility, but it might not be guaranteed. So if you happen to run your application (like me :) ) it is because of the backward compatibility of ASP.NET. At the end the application runs on ASP.NET 2.0 worker process.

C:\\Program Files\\Microsoft Visual Studio 8\\VC> gacutil /l System.Data
Microsoft (R) .NET Global Assembly Cache Utility.  Version 2.0.50727.42
Copyright (c) Microsoft Corporation.  All rights reserved.

The Global Assembly Cache contains the following assemblies:
  System.Data, Version=, Culture= neutral, PublicKeyToken= b77a5c561934e089
, processorArchitecture=x86

Number of items = 1

C:\Program Files\Microsoft Visual Studio 8\VC>

Running Web Application

All the code without change can work on IIS7. You can migrate your code to ASP.NET 2.0 but this is not a necessity. With a little configuration on IIS server you will be able to run your 1.1 compiled applications.

  • After you open the IIS Manager (still inetmgr.exe), you either “Add Application” or “Convert to Application” to create your web application. With “Add Application” you will be able to choose any directory in your computer, but with “Convert to Application” you will only be able to choose from the virtual directories which is located under inetpub\wwwroot.

Convert Application

  • We see “Add Application” dialog box opened. From there we select Application Pool to change DefaultAppPool.

Add Application

  • We select Classic .Net AppPool from the “Select Application Pool” dialog.

Classic Pool

  • Then we’re ready to go after setting the application pool to Classic .Net AppPool


  • When we click browse, or look directly to the virtual directory, our site is up and running



One more thing, to debug your application you need to switch the application to windows authentication mode. This has also been changed in IIS7.

  • In IIS Manager select from left, the web application virtual directory, then from right select authentication under IIS section.


  • Then enable windows authentication to be able to debug your application.