Running 32-bit Server Applications on 64-bit Machines

Running 32-bit Applications on 64-bit Windows (IIS 6.0)

Windows Server 2003™, Service Pack 1 enables IIS 6.0 to run 32-bit Web applications on 64-bit Windows using the Windows-32-on-Windows-64 (WOW64) compatibility layer. IIS 6.0 using WOW64 is intended to run 32-bit personal productivity applications needed by software developers and administrators, including 32-bit Internet Information Services (IIS) Web applications.

On 64-bit Windows, 32-bit processes cannot load 64-bit DLLs, and 64-bit processes cannot load 32-bit DLLs. If you plan to run 32-bit applications on 64-bit Windows, you must configure IIS to create 32-bit worker processes. Once you have configured IIS to create 32-bit worker processes, you can run the following types of IIS applications on 64-bit Windows:

•	Internet Server API (ISAPI) extensions
•	ISAPI filters
•	Active Server Page (ASP) applications (specifically, scripts calling COM objects where the COM object can be 32-bit or 64-bit)
•	ASP.NET applications

IIS can, by default, launch Common Gateway Interface (CGI) applications on 64-bit Windows, because CGI applications run in a separate process.

Configuring IIS to run 32-bit Web applications on 64-bit Windows

Before you configure IIS to run 32-bit applications on 64-bit Windows, note the following:

•	IIS only supports 32-bit worker processes in Worker Process Isolation mode on 64-bit Windows.
•	On 64-bit Windows, the World Wide Web Publishing service can run 32-bit and 64-bit worker processes. Other IIS services like the IIS Admin service, the SMTP service, the NNTP service, and the FTP service run 64-bit processes only.
•	On 64-bit Windows, the World Wide Web Publishing service does not support running 32-bit and 64-bit worker processes concurrently on the same server. To enable IIS 6.0 to run 32-bit applications on 64-bit Windows 1. Enable IIS's 32-bit support Open a command prompt and type in the following command: cscript %SYSTEMDRIVE%\inetpub\adminscripts\adsutil.vbs SET W3SVC/AppPools/Enable32bitAppOnWin64 1 This command enables the 32-bit mode in IIS. 2. Install the IIS 32-bit extensions Open a command prompt and type the following command: %SYSTEMROOT%\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis.exe -i This command installs the 32-bit web extensions for .NET Framework 2.0. 3. Activate .NET Framework 2.0 32-bit in IIS In the IIS-Manager, select the 'ASP.NET v2.0.50727 (32bit)' in the 'Web Service Extensions' panel and check 'allow' to activate it. 4. Restart the IIS by opening a command prompt: iisrestart