XFOR: "WHO" Command Disabled to Increase Chat Server Performance (258982)

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

SUMMARY

The Exchange 2000 Chat service allows channel participants to issue the Internet Relay Chat Extension (IRCX) WHO command, which returns a list of all chat participants that are currently connected to the chat server. The cost of this feature is very high and may significantly affect the performance the service. To avoid this negative effect, the WHO command has been disabled by default. To use the WHO command, you must enable it in the registry.

MORE INFORMATION

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

Start Registry Editor (Regedt32.exe).
Locate the following key in the registry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\MSExchangeChat\Parameters
NOTE: If the RestrictWho value does not already exist, on the Edit menu, click Add Value, and then add the following registry value:
- Value Name: RestrictWho
- Data Type: REG_DWORD
- Value: 0

NOTE: Earlier version of the Exchange Chat service support the RestrictWho registry setting with various levels of support such as no restrictions, no parameters, or global wildcards. The Exchange 2000 Chat service, however, does not support any of these registry parameters. The WHO command is either enabled or disabled.