how to prevent user from sending exchange 2003

Connector Delivery Restrictions May Not Work Correctly
http://support.microsoft.com/kb/277872/
Start Registry Editor (Regedt32.exe).Locate and click the following registry key:HKEY_LOCAL_MACHINE/System/CurrentControlSet/Services/Resvc/Parameters/ On the Edit menu, click Add Value, and then add the following registry value:Value Name: CheckConnectorRestrictionsData Type: REG_DWORDRadix: HexadecimalValue: 1 Quit Registry Editor.