IIS 6.0 Application Isolation Modes Overview

In order to separate and protect ASP.NET applications that run simultaneously, Internet Information Services (IIS) 6.0 provides two different application isolation modes. By default, worker process isolation mode is used. However, IIS 5.0 isolation mode is also provided for backward compatibility. The following sections describe the two application isolation modes and how to set the mode.

Worker Process Isolation Mode

The default application isolation mode in IIS 6.0 is worker process isolation mode. In this mode, the process model built into ASP.NET is disabled, and the worker process isolation architecture of IIS 6.0 is used instead. Any configuration settings that are specified in the <processModel> element of the Machine.config file are disregarded, except for the following attributes:

• maxWorkerThreads
• maxIoThreads
• responseDeadlockInterval

To specify values for other process model attributes, you must use the appropriate application pool setting. For information about setting the appropriate application pool settings, see Application Pool Settings for Worker Process Isolation Mode.

IIS 5.0 Isolation Mode

When IIS 6.0 is in IIS 5.0 isolation mode, the worker process isolation architecture of IIS 6.0 is disabled and the process model build into ASP.NET is used for all ASP.NET applications on the computer. In this mode, the process model settings are specified through the <processModel> element of the Machine.config file.

For more information on configuring the process model settings when using IIS 5.0 isolation mode, see ASP.NET Configuration.

Setting the Application Isolation Mode

When using IIS 6.0, you can select either worker process isolation mode or IIS 5.0 isolation mode. The application isolation mode applies globally to the IIS service and affects all Web applications on the computer. You cannot apply an application isolation mode to individual applications.

To select the application isolation mode in IIS 6.0

1. Open the IIS management console and expand the local computer by clicking the plus sign.
2. Right-click the Web Sites folder, click Properties, and then click the Service tab.
3. Under Isolation mode, select or clear the Run Web service in IIS 5.0 isolation mode check box to select either IIS 5.0 isolation mode or worker process isolation mode, respectively.

Service tab of the Web Sites Properties dialog box

See Also

IIS 6.0 Application Isolation Modes | Mapping ASP.NET Process Model Settings to IIS 6.0 Application Pool Settings | Application Pool Settings for Worker Process Isolation Mode | ASP.NET Configuration | <processModel> Element