Microsoft KB Archive/820129

= Http.sys registry settings for IIS =

Article ID: 820129

Article Last Modified on 12/3/2007

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APPLIES TO


 * Microsoft Internet Information Services 6.0

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Important This article contains information about how to modify the registry. Make sure that you back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry



SUMMARY
In Microsoft Windows Server 2003, Http.sys is the kernel mode driver that handles HTTP requests. Several registry values can be configured according to specific requirements. The table in the &quot;More Information&quot; section contains the following information about these registry values:
 * Registry key names
 * Default values
 * Valid value ranges
 * Registry key functions
 * WARNING codes (where appropriate)

Note See the &quot;WARNING Codes&quot; section for information about potential risks when you create and configure registry values by using settings other than the default settings.

This article is intended for advanced users and assumes knowledge of the registry and of the risks that are involved when the registry is changed.



MORE INFORMATION
Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

You can create the following DWORD values under the following registry key:

You may experience slow performance in Microsoft Internet Information Services (IIS) 6.0 when Internet Server API (ISAPI) applications or Common Gateway Interface (CGI) applications that are hosted on IIS 6.0 send responses. If you experience this issue, you can add the MaxBufferedSendBytes DWORD value to the registry. For more information about this issue, click the following article number to view the article in the Microsoft Knowledge Base:

906977 BUG: You experience slow performance when ISAPI applications and CGI applications that are hosted on Internet Information Services 6.0 send responses

In Microsoft Windows XP and in Microsoft Windows Server 2003, you can also create the following DWORD value under the following registry key:

WARNING codes

 * 0: No risks.
 * 1: Changing this registry key is considered extremely dangerous. This key causes Http.sys to use more memory and may increase vulnerability to malicious attacks.
 * 2: A low value may cause the cache to be flushed more frequently. If this behavior occurs, it may affect performance.
 * 3: A low value may affect performance for static content.

Changes that are made to the registry will not take effect until you restart the HTTP service. Additionally, you may have to restart any related IIS services.

To restart the HTTP service, type and all related IIS services, follow these steps:
 * 1) Click Start, click Run, type Cmd and then click OK.
 * 2) At the command prompt, type net stop http at a command prompt and then press ENTER.
 * 3) At the command prompt, type net start http at a command prompt and then press ENTER.
 * 4) At the command prompt, type net stop iisadmin /y at a command prompt and then press ENTER.

Note Any IIS services that depend on the IIS Admin Service service will also be stopped. Notice the IIS services that are stopped when you stop the IIS Admin Service service. You will restart each service in the next step.
 * 1) Restart the IIS services that were stopped in step 4. To do this, type net start  at the command prompt and then press ENTER. In the command,   is the name of the service that you want to restart. For example, to restart the World Wide Web Publishing Service service, type net start &quot;World Wide Web Publishing Service&quot;, and then press ENTER.

Keywords: kbinfo KB820129

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