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Generate a Machine Key for a Web Farm (IIS 7)

Applies To: Windows 7, Windows Server 2008, Windows Server 2008 R2, Windows Vista

To use Forms authentication across multiple computers in a Web farm configuration, you must manually generate specific values for validation and decryption keys, and you must use those values on all computers in the Web farm.


For information about the levels at which you can perform this procedure, and the modules, handlers, and permissions that are required to perform this procedure, see Machine Keys Feature Requirements (IIS 7).

Exceptions to feature requirements

  • None

To generate a machine key for a Web farm

You can perform this procedure by using the user interface (UI), by editing configuration files directly, or by writing WMI scripts.

User Interface

To Use the UI

  1. Open IIS Manager and navigate to the level you want to manage. For information about opening IIS Manager, see Open IIS Manager (IIS 7). For information about navigating to locations in the UI, see Navigation in IIS Manager (IIS 7).

  2. In Features View, double-click Machine Key.

  3. On the Machine Key page, to generate specific validation and decryption key values for a Web farm, clear Generate a unique key for each application for both validation and decryption keys, clear Automatically generate at runtime, and then click Generate Keys in the Actions pane to create specific key values.

  4. In the Actions pane, click Apply.


The procedure in this topic affects the following configuration elements:

<machineKey> element, defined in Machine.config file.

For more information about IIS 7 configuration, see IIS 7.0: IIS Settings Schema on MSDN.


Use the following WMI classes, methods, or properties to perform this procedure:

  • MachineKeySection class

For more information about WMI and IIS, see Windows Management Instrumentation (WMI) in IIS 7. For more information about the classes, methods, or properties associated with this procedure, see the IIS WMI Provider Reference on the MSDN site.

See Also


Configuring Machine Keys in IIS 7