OK, problem, the exchange 2010 server was spewing out the internal server name in the header of a SMTP connection 220 internal.domain.local Microsoft ESMTP MAIL Service ready at Sun, 15 Aug 2010 03:23:18 -0400. Needless to say, that's bad. I wanted it to show the external name of the server. So, I set out to find it. Turns out you can't do it through the Management Console. You have to pop open the management shell. You can get the name using the management console, or to find it using the mana