ISA Server may cause non-paged pool memory peaks (321844)


The information in this article applies to:

  • Microsoft Internet Security and Acceleration Server 2000
  • Microsoft Internet Security and Acceleration Server 2000 SP1
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

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 fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

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.
Modification Type:MinorLast Reviewed:6/20/2006
Keywords:kbQFE KBHotfixServer kbbug kbfix KB321844
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