How to Fix the Link-State Suppression Error.

How to Fix the Link-State Suppression Error.

Its a very good practice to run the Exchange Best Practices Analyzer (ExBPA) before you start installing your Exchange 2007 domain. This tool checks the prerequites for installing the Exchange 2007. But a common problem that the ExBPA shows during Exchange 2007 Readiness Check is the "Link State Suppression is not enabled" error. If you have Exchange 2003 in the existing organisation which is having more than one routing group then suppress the link state information. This paramemeter is essential if you plan to create multiple connectors to the dedicated Exchange 2007 routing group.

In earlier versions of Exchange, when a target server was unreachable, the down connector state was propagated throughout the Exchange organization by link state updates, and an alternative route was calculated. In Exchange 2007, when a message can't be relayed directly to the target server because of network problems, no alternative route is calculated. The message queues on a Hub Transport server in the closest reachable site to the point of failure. The purpose of this procedure is to make sure that routing loops cannot occur. So that’s why we need to set it to value 1 in the registry.

Inorder to set the registry follow the below step:

1. Open Registry Editor.

2. Locate HKEY_LOCAL_MACHINE\System\CurrentControlSet

\Services\RESvc\Parameters.

3. Right-click Parameters and select New DWORD value. Name the new DWORD value SuppressStateChanges.

4. Double-click SuppressStateChanges.

5. In the Value data field, enter 1.

6. Close Registry Editor and then restart the Simple Mail Transfer Protocol (SMTP) service, the Microsoft Exchange Routing Engine service, and the Microsoft Exchange MTA Stacks services for the change to take effect.

Note: You have to do it on each exchange 2000\2003 server if you have more than one routing group connector.