XIMS: WHO Command with Wildcard Characters Causes Server to End Portal Connection

ID: q236311

The information in this article applies to:
  • Microsoft Exchange Server, version 5.5
IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SYMPTOMS

If you repeatedly send the WHO command with a wildcard character as a parameter to a Microsoft Exchange Chat Service computer, and the server is connected to another Microsoft Exchange Chat Service computer through a portal, the second server may eventually end the portal connection unexpectedly. This includes the following combinations of the asterisk (*) and question mark (?) wildcard characters, which match all strings:

  • *
  • ?*
  • '*
  • '?*
Note that this problem occurs if the wildcard character (or combination of wildcard characters) is the only parameter or if it is included in a list of multiple parameters.

In addition, if you send the WHO command with a parameter terminated by a comma, the server performs a search based on the specified parameter, and then performs an additional search as if a wildcard character had also been specified. This may cause the above problem to occur.


CAUSE

This problem occurs when the output saturation limit on the server to which you are connected is very high. When you send the WHO command with a wildcard character, the command returns a large amount of data. If the output saturation limit is very high, the output buffer on the server to which you are connected may become very large, which in turn causes the portal buffer on the second server to become very large. If the buffers become large enough, the second server ends the portal connection.


RESOLUTION

To resolve this problem, obtain the latest service pack for Exchange Server version 5.5. For additional information, please see the following article in the Microsoft Knowledge Base:

Q191014 XGEN: How to Obtain the Latest Exchange Server 5.5 Service Pack
The English version of this fix should have the following file attributes or later:

Component: Chat Service

File name Version
Chatsvc.exe 5.5.2632.0

After you apply the fix, configure the server to ignore WHO commands that are sent with a wildcard character as a parameter. To do so:

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).
  1. Start Registry Editor (Regedt32.exe).


  2. Locate the following key in the registry:


    3. HKEY_LOCAL_MACHINE\Software\Microsoft\Exchange\ChatSvc\Parameters
  3. If the RestrictWho value already exists under the above key, on the Edit menu, click DWORD, type 2, and then click OK.

    If the RestrictWho value does not already exist, on the Edit menu, click Add Value, and then add the following registry value:


    4. Value Name: RestrictWho
    Data Type: REG_DWORD
    Value: 2
  4. Quit Registry Editor.



WORKAROUND

To work around this problem, lower the output saturation limit on the server:

  1. Start the Microsoft Management Console (MMC). To do so, click Start, point to Programs, point to Microsoft Exchange Chat Service, and then click Chat Service Manager.


  2. In the left pane, click the User Classes folder under the appropriate server. Note that the server appears under the Microsoft Exchange Chat Service folder.


  3. In the right pane, click a user class, click Action, and then click Properties.


  4. Click the Settings tab, type a smaller value in the Output saturation limit (kilobytes) box, and then click OK.


  5. Repeat steps 3 and 4 for any additional user classes that are listed in the right pane.



STATUS

Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. This problem was first corrected in Exchange Server 5.5 Service Pack 3.


MORE INFORMATION

This problem does not occur when the output saturation limit is low, because the server automatically ends the connection to the client before the buffers become too large.

Additional query words: star hub leaf

Keywords : exc55 EXC55SP3Fix
Version : winnt:5.5
Platform : winnt
Issue type : kbbug


Last Reviewed: September 28, 1999
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