In Exchange 2007, you have a nice little GUI to set your FQDN on your Send Connector. (Mine is called Outbound, as shown below.)
You can see my FQDN, set under the Hub Transport/Send Connectors of the Exchange Management Console.
However, if you send mail out to an external address, you’ll notice in the headers that your internal server name is still listed! What!? What’s the point of the GUI?
You have top open Exchange Management Shell, and type in a command to solve this. It’s easy.
As shown above, you just type in the command:
set-sendconnector “Outbound” â€“fqdn mail.1stbyte.com
Replace “outbound” with the name of your send connector, and of course, change to your own FQDN, not mine.
It will come back in error, or success. If success, you can check your headers on and external account right away.