MaxActiveQueries has been modified

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at]  

Topic Last Modified: 2009-08-17

The Microsoft® Exchange Server Analyzer Tool queries the Active Directory® directory service to determine the maximum number of Lightweight Directory Access Protocol (LDAP) queries that can be processed at the same time. This value is obtained by examining the current LDAP administrative policies. Specifically, the Exchange Server Analyzer checks for the presence of MaxActiveQueries. If the Exchange Server Analyzer determines that MaxActiveQueries exists and is configured with a value of anything other than 20, a non-default configuration message is displayed.

The LDAP administrative limits balance the Active Directory operational capabilities and its performance. These limits prevent specific operations from adversely affecting the performance of the server. Increasing this setting beyond its default value could have an adverse effect on your Active Directory infrastructure.

The MaxActiveQueries value of the LDAPAdminLimits attribute controls the maximum number of simultaneous LDAP queries for the default query policy. By default, a limit of 20 active queries is imposed. If this limit is reached, Active Directory returns "LDAP_ADMIN_LIMIT_EXCEEDED" and does not process additional LDAP queries.

To modify MaxActiveQueries , use Ntdsutil.exe. Ntdsutil.exe is located in the Support\Tools folder on the Microsoft Windows® 2000 Server installation CD-ROM. By default, Ntdsutil.exe is installed in the System32 folder.

To start Ntdsutil.exe

  1. Click Start, and then click Run.

  2. In the Open text box, type ntdsutil, and then press Enter. To view Help at any time, type ? at the command prompt.

To view policy settings

  1. At the Ntdsutil.exe command prompt, type LDAP policies, and then press Enter.

  2. At the LDAP policy command prompt, type connections, and then press Enter.

  3. At the server connection command prompt, type connect to server DNS name of server, and then press Enter. You want to connect to the server that you are currently working with.

  4. At the server connection command prompt, type q, and then press Enter to return to the previous menu.

  5. At the LDAP policy command prompt, type Show Values, and then press Enter.

    A display of the policies as they exist appears.


This procedure shows only the Default Domain Policy settings. If you apply your own policy setting, you cannot see it.

To change policy settings

  1. At the Ntdsutil.exe command prompt, type LDAP policies, and then press Enter.

  2. At the LDAP policy command prompt, type Set MaxActiveQueries to 20, and then press Enter.

    You can use the Show Values command to verify your changes.

  3. To save the changes, use Commit Changes.

  4. When you finish, type q, and then press Enter.

  5. To quit Ntdsutil.exe, at the command prompt, type q, and then press Enter.

For more information about configuring LDAP policies, see the Microsoft Knowledge Base article 315071, "How to view and set lightweight directory access protocol policies by using Ntdsutil.exe in Windows 2000" (