Connector restriction checking is enabled

[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: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry branch to determine if the CheckConnectorRestrictions registry value is present and configured:


If the Exchange Server Analyzer finds the value for CheckConnectorRestrictions present and set to 1, a warning is displayed.

If you need to apply a distribution list-based restriction to a connector, you must manually enable the checking process for these restrictions. Restriction checking is controlled by the CheckConnectorRestrictions registry value that must be set on the Exchange bridgehead server that is the source for the connector that is being checked. If you specify a restriction, but do not create the CheckConnectorRestrictions registry value, the restriction is not checked.

Connector restriction checking is turned off by default because expanding distribution groups and checking the restrictions for each message that passes through the system can significantly impact performance. If possible, enable this setting only where it is necessary (for example, on the bridgehead server for the restricted connector).


This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.

To disable connector restriction checking

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to:

  3. In the right-hand pane, locate CheckConnectorRestrictions and delete it.

  4. Close the registry editor and restart the Microsoft Exchange Routing Engine service and the Simple Mail Transfer Protocol (SMTP) service for the change to take effect.

For more information about how to edit the registry, see Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (

For more information about the connector restriction checking registry value, see Microsoft Knowledge Base article 277872, "XCON: Connector Delivery Restrictions May Not Work Correctly" (