If the newly upgraded IIS 6.0 server includes existing ASP.NET applications, you need to configure IIS to use the correct version of the .NET Framework, and you must configure the .NET Framework to support your applications. If IIS 6.0 is configured to run in worker process isolation mode, you need to migrate ASP.NET configuration settings from the Machine.config file to the equivalent settings in IIS 6.0.
Figure 5.6 illustrates the process for configuring IIS for ASP.NET applications
Figure 5.6. Configuring IIS for ASP.NET Applications