ISA Server Intermittently Stops Responding to Web Proxy Client Requests

Your Microsoft Internet Security and Acceleration (ISA) Server 2000 server may intermittently stop responding to Web Proxy client requests. When you troubleshoot this problem, you notice all the following symptoms:

• The Lsass.exe process uses a very high percentage of memory and continues to increase memory usage.
• If you stop the Microsoft Web Proxy service (W3Proxy.exe), the Lsass.exe process does not use additional memory, but it does not release the memory that it currently has allocated.
• If you restart the server, the problem is resolved.

This problem may occur if you configure the Microsoft Web Proxy service to authenticate outgoing Web Proxy client requests. The Microsoft Web Proxy service does not correctly release security context handles when it authenticates these client requests. This causes the Lsass.exe process to use additional memory resources. After the Lsass.exe process has used a lot of memory, the Microsoft Web Proxy service can no longer authenticate these outgoing requests and, as a result, stops responding to client requests.

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: 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. The English version of this hotfix has the file attributes (or later) 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 tool in Control Panel.

Microsoft has confirmed that this is a problem in Microsoft Internet Security and Acceleration Server 2000.