Restriction settings are not applied after you configure the Delivery Restrictions option in Exchange Server

In Microsoft Exchange 2000 Server or Exchange Server 2003, after you configure the Delivery Restrictions option on a connector, the restriction settings may not be applied.

The restriction checking functionality is controlled by a registry key that is set on the Exchange bridgehead server that is the source for the connector that is being checked. If you need to apply a restriction to a connector which restricts who is able to send data to the designated link, you must manually add the restriction checking registry value.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To enable restriction checking:

1. Start Registry Editor (Regedt32.exe).
2. Locate and click the following key in the registry:
   HKEY_LOCAL_MACHINE/System/CurrentControlSet/Services/Resvc/Parameters/
3. On the Edit menu, click Add Value, and then add the following registry value:
   Value Name: CheckConnectorRestrictions
   Data Type: REG_DWORD
   Radix: Decimal
   Value: 1
4. Quit Registry Editor.

After you make the change to the registry, restart any related Internet Information Services (IIS) services, click the connector, and then click the Delivery Restrictions tab to enable the restriction option.

This feature is by design.

When you enable the Delivery Restrictions option, the computers performance may be affected. When you set the registry value, every message for every destination is checked.