Routing Engine: SuppressStateChanges parameter is non-default
[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 https://go.microsoft.com/fwlink/?linkid=34707.]
Topic Last Modified: 2005-11-18
The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine whether Simple Mail Transfer Protocol (SMTP) connector routing logic has been modified from its default setting:
If the Exchange Server Analyzer finds that the SuppressStateChanges registry key is present and configured with a value greater than 0, a non-default configuration message is displayed.
Exchange Server 2003 includes functionality to detect automatically changes in the state of a link. This information can be used to inform other servers running Exchange Server 2003 that an alternative route should be used instead of the lowest cost primary route. Link state information is divided into major and minor changes. A major change occurs when the administrator changes the routing topology, such as the addition of a new connector or a cost change. Minor updates occur when the system automatically detects the failure or restoration of a link.
This feature works well in small to medium-sized organizations. However, in large multi-site environments, mass network fluctuation can cause link update floods for the minor version. To be truly effective, link state data must be broadcast to all the servers in the organization. Additionally, when state changes, the whole link state table is rebroadcast, which can cause a significant amount of data to be transmitted over the network. In these scenarios, it may be useful to suppress minor link state changes. The SuppressStateChanges registry entry is a custom configuration setting used to suppress minor link state changes. When SuppressStateChanges is set to greater than 0, all link state changes on this Exchange Server computer are suppressed.
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 revert to the default configuration
Open a registry editor, such as Regedit.exe or Regedt32.exe.
Navigate to: HKLM\System\CurrentControlSet\Services\RESvc\Parameters
Delete the SuppressStateChanges registry key.
Close the registry editor.
Restart the Simple Mail Transfer Protocol (SMTP), the Microsoft Exchange Routing Engine, and the Microsoft Exchange MTA Stacks services for the change to take effect.
Before you edit the registry, and for information about how to edit the registry, see Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (https://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).
For more information about the SuppressStateChanges registry key, see the following Microsoft guides: