Limiting logons to the Information Store in Exchange Server

Exchange Server administrators can limit the users who are allowed to log on to the information store. This can be useful when you need to perform maintenance or upgrades to the Exchange Server computer and if you need to keep users from logging on to Exchange.

To limit the users who are allowed to log on to the information store you need to edit the registry.

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.
To limit allowed users:

1. Stop the Information Store service on the Exchange Server computer.
2. Start Registry Editor (Regedt32.exe).
3. Locate the following key in the registry:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
4. On the Edit menu, click Add Value, and then add the following registry value:
   Value Name:Enable Tracing
   Data Type: REG_DWORD
   Radix: Decimal
   Value data: 1
5. Click OK. In the Data box, type the distinguished names of the users that you want to allow to log on to the information store on separate lines, and then click OK. For example:
   /o=microsoft/ou=apps-wga/cn=recipients/cn=user1
   /o=microsoft/ou=apps-wga/cn=recipients/cn=user2
   For more information about how to prevent problems with the Internet Mail Service, click the following article number to view the article in the Microsoft Knowledge Base:
   306308  (http://support.microsoft.com/kb/306308/ ) The Internet Mail Service does not start when limiting logons to the Information Store
6. Click OK.
7. Quit Registry Editor.
8. Restart the Information Store service.

This procedure allows only those users entered in the registry parameter to log on to the information store. Users who are not specified in the registry parameter receive the following error message when they try to connect to the information store: NOTES:

• Leaving the registry parameter blank prevents all users from logging on to the information store.
• To allow all users to again log on to the information store, you must remove the registry key. To remove the registry key:
  1. Stop the Information Store service on the Exchange Server computer.
  2. Start Registry Editor (Regedt32.exe).
  3. Locate the Logon Only As value under the following key in the registry:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem
  4. Click the Logon Only As value in the right pane.
  5. On the Edit menu, click Delete.
  6. Quit Registry Editor.
  7. Restart the Information Store Service.

For more information about how to accomplish this with Exmerge, click the following article number to view the article in the Microsoft Knowledge Base: