Required registry setting when using SMTP Connector as a site connector to Exchange Server 5.5

When you use the Exchange 2000 SMTP Connector as a site connector to an Exchange Server 5.5 site, you need a required registry setting for proper mail flow of system messages.

When sending a summary TNEF (S-TNEF) message, SMTP does not know that the message is binary MIME, and therefore tries to send the message using the DATA command instead of the BDAT command, as the BDAT command is not advertised on an Exchange Server 5.5 computer.

To resolve this problem, add the following key to the registry:

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.

1. Start Registry Editor (Regedt32.exe).
2. Locate the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange
3. On the Edit menu, click Add Key, and then add the following registry key:
   Key Name: StoreDriver
   Class: (leave this blank)
4. On the Edit menu, click Add Key, and then add the following registry key:
   Key Name: Exchange
   Class: (leave this blank)
5. On the Edit menu, click Add Key, and then add the following registry key:
   Key Name: 1
   Class: (leave this blank)
   
   Note After you add the keys in steps 3 through 5, you will be in the following key in the registry:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange\StoreDriver\Exchange\1
6. On the Edit menu, click Add Value, and then add the following registry value:
   Value Name: EnableTnef
   Data Type: REG_DWORD
   Data: 1
7. Quit Registry Editor.

This registry setting forces the store driver to use TNEF instead of S-TNEF, and as a result, using the SMTP DATA command will not be a problem.

Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server.