The performance of the server deteriorates over time after you enable Sender ID Filtering in Exchange Server 2003 Service Pack 2

After you enable Sender ID Filtering on a server that is running Microsoft Exchange Server 2003 Service Pack 2 (SP2), the performance of the Exchange server deteriorates over time. If you run the following command at a command prompt, you can notice that there are many connections to the SMTP port that are in a state of CLOSE_WAIT:Additionally, you experience the following symptoms:

• Client computers cannot make any new SMTP connections to the Exchange server.
• You cannot restart the World Wide Web Publishing Service. You have to kill and then restart the inetinfo.exe process by running the following command:
  iisreset /restart

Note To enable Sender ID Filtering, you must configure options on the General tab of the Message Delivery object properties dialog box in Exchange System Manager. Additionally, you must click to select the Apply Sender ID Filter check box under the IP address area of the Default SMTP Virtual Server properties dialog box.

This problem occurs because of an accumulation of process threads that are blocked in filtering operations. The blocked process threads wait indefinitely to complete validating the sender as part of the Sender ID validation process.

Hotfix information

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.

Prerequisites

You must install Exchange Server 2003 Service Pack 2 (SP2) before you apply the hotfix. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

Restart requirement

You do not have to restart the computer after you apply the hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The global 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.

To work around this problem, you can free blocked process threads in the filtering process. To do this, restart Internet Information Services (IIS). You may have to restart IIS one time a month. If you cannot restart the World Wide Web Publishing Service from the Services snap-in, you may have to kill the inetinfo.exe process and then restart it. To do this, run the following command at a command prompt:

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

For more information about the terminology that is used to describe Microsoft software updates, click the following article number to view the article in the Microsoft Knowledge Base: For more information about the naming schema for Exchange Server software updates, click the following article number to view the article in the Microsoft Knowledge Base: