Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool queries the Exchange_DSAccessDC Microsoft Windows® Management Instrumentation (WMI) class in the ROOT\MicrosoftExchangeV2 namespace to determine the value for the IsUp key. If the IsUp key is set to False, an error is displayed.

If the IsUp key is set to True, it indicates that the domain controller responded the last time the Exchange server tried to establish a connection. If IsUp is set to False, it indicates that the domain controller did not respond to connection attempts.

The lack of response does not always mean that the domain controller or global catalog is down or malfunctioning. Sometimes, there may network connectivity issues between the Exchange server and the domain controller that could cause this failure. Such a failure could also be the result of a firewall between the Exchange server and the domain controller on which the appropriate ports have not been opened.

To correct this error

  1. Check that the domain controller is running by trying to ping to it.

  2. If there is a firewall, make sure that the firewall has the correct ports open. Be aware that firewalls can be configured to drop PING packets also. Check your firewall documentation for details about how to open or close specific ports.

  3. Make sure that there are no other network related issues, such as malfunctioning switches, routers, and cables.

For more information about DSAccess and directory services detection, see the Microsoft Knowledge Base article 250570, "Directory Service Server Detection and DSAccess Usage" (

For more information about troubleshooting network connectivity issues, see the Knowledge Base article 325487, "How to troubleshoot network connectivity problems" (