ISA Server may cause non-paged pool memory peaks

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Article ID: 321844 - View products that this article applies to.
This article was previously published under Q321844
Important This article contains information about how to modify the registry. Make sure to 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
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SYMPTOMS

In Microsoft Internet Security and Acceleration (ISA) Server 2000, you may experience slow response or be completely unable to establish sessions through ISA. For example, you may experience slow response or be unable to connect to Web sites through ISA.

When you monitor memory usage on the ISA Server by using, for example, Performance Monitor, you may see extensive peaks in user mode and non-paged pool memory consumption.

Additionally, you may see events similar to the following logged in the Event Viewer.

Event message 1
Event Type: Error
Event Source: Srv
Event Category: None
Event ID: 2019
Date: "date"
Time: "time"
User: N/A
Computer: "computername"

Description:
The server was unable to allocate from the system nonpaged pool because the pool was empty.
Event message 2
Event Type: Error
Event Source: Microsoft Web Proxy
Event Category: None
Event ID: 14198
Date: "date"
Time: "time"
User: N/A
Computer: "computername"

Description:
The Web Proxy service failed to create a network socket because there are no available ports on this computer. ISA server already reset the maximal port number to 65535. Make sure this is the value at HKLM\System\CurrentControlSet\Service\TcpIp\Parameters\MaxUserPort and restart the computer to apply this change.
Note that you may not see all of these symptoms.

CAUSE

The peak in the memory usage may be seen when the data retrieval rate between ISA and the Web server that hosts the content is faster than the data sending rate between ISA and the requesting client. Typically this may be seen when content is served from the Web Proxy cache or if the link between ISA and the Web server that hosts the content is faster than the link between ISA and the internal client that sends the request.

RESOLUTION

This hotfix for the HTTP redirector application filter limits the number of pending sends on the internal socket between the HTTP client and ISA.

You must install ISA Server Service Pack 1 (SP1) before you apply the following hotfix. For more information about how to obtain the latest ISA Server service pack, click the following article number to view the article in the Microsoft Knowledge Base:
313139 How to obtain the latest Internet Security and Acceleration Server 2000 service pack
This issue has been fixed in ISA Feature Pack 1. For more information about how to obtain Feature Pack 1, click the following article number to view the article in the Microsoft Knowledge Base:
319380 ISA Server 2000 Feature Pack 1 Overview
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/?ws=support
Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language. To install the fix, run the self-extracting file. You do not have to restart the ISA Server computer. If the computer is part of an ISA Server array, you do not have to shut the whole array down; you can still install this fix on a one-by-one basis.

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
   Date         Time   Version          Size  File name
   -------------------------------------------------------
   2-June-2002  18:33  3.0.1200.176   51,984  Httpfltr.dll
   2-June-2002  18:31  3.0.1200.176  386,320  W3proxy.exe
   2-June-2002  18:32  3.0.1200.176   99,600  Msphlpr.dll
				
This fix also applies to the French, German, Spanish, and Japanese versions of ISA Server.

The binary fix for the issue that is described in this article is Httpfltr.dll. The hotfix does, however, include updates to three binaries, because the hotfix package also resolves another issue that is referenced in the "More Information" section.

WORKAROUND

Instead of installing this hotfix, you can disable the HTTP redirector application filter if it is not required.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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 your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.
This issue has been fixed in ISA Feature Pack 1.

To implement the functionality in this fix and then enable it, follow these steps after you have installed the fix:
  1. Stop the Firewall service.
  2. Start Registry Editor.
  3. Locate and select the following registry key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fpc
  4. Under Fpc, create a new key named PluginHTTP.
  5. Locate and select the following registry key:
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fpc\PluginHTTP
  6. Create a new DWORD value named MaxPendingSendsPerConnection. Give this new value a data value of 20 (Decimal).
  7. Restart the Firewall service.
To revert to the original configuration, either remove the MaxPendingSendsPerConnection registry value or change its data value to FFFFFFFF (Hexadecimal). After you make either change, restart the Firewall service.

Properties

Article ID: 321844 - Last Review: June 14, 2007 - Revision: 7.5
APPLIES TO
  • Microsoft Internet Security and Acceleration Server 2000 Standard Edition
  • Microsoft Internet Security and Acceleration Server 2000 Service Pack 1
Keywords: 
kbautohotfix kbqfe kbhotfixserver kbbug kbfix KB321844

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