Transition: Link state on E2K3 and E2K7 HT server
When you install a Hub server in an existing E2K3 organization which hosts multiple routing groups, the first 2007 Routing Group Connector is automatically created.
Before implementing any additional connectors you may need, edit the Registry on each Exchange 2003 server to suppress propagation of minor link state updates between the 2003 and 2007 routing groups. This will prevent routing loops.
On each Exchange 2003 server:
1. Launch Regedit.
2. Locate HKLM\System\CurrentControlSet\Services\RESvc\Parameters.
3. Right-click Parameters. Select New > DWORD value. Name it SuppressStateChanges.
4. Double-click SuppressStateChanges.
5. In the Value data field, enter 1.
6. Close Regedit.
7. Restart the SMTP, Routing Engine, and MTA Stacks Services for this change to take place.