Global catalog port 3268 not responding

[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: 2005-11-17

The Microsoft® Exchange Server Analyzer Tool queries Active Directory® directory service to determine the value of the isGlobalCatalogReady attribute of this server. A value of True for this attribute indicates that the directory server is also a functioning global catalog server, and a value of False indicates that the directory server is not a global catalog server

Then the Exchange Server Analyzer connects to port 3268 on the Exchange server to verify that the port is responding.

The Exchange Server Analyzer displays an error if the following conditions are true:

  • The server is a global catalog server.

  • The port 3268 is not responding.


This message may be displayed in error if there is a firewall between the computer running the Exchange Server Analyzer and the global catalog server.

This problem typically occurs when the global catalog server check box has been selected but the server has not been restarted.

To correct this issue

  • Restart the server.

For more information about promoting domain controllers, see Microsoft Knowledge Base article 304403, "XADM: Exchange Considerations for Promoting a Domain Controller to a Global Catalog Server" (