I have an Exchange 2007 Server setup and I need to configure TLS encryption for this system. We send all of our outbound messages to Postini, and in order to setup secure email we are required to force TLS on the server so that only TLS encrypted messages are sent from our server to theirs. In fact, any message which tries to go out as unencrypted SMTP, will simply bounce back from their server and state that TLS encryption is required. We have a certificate from VeriSign installed on the system and is appears that everything is registered correctly, but for some reason the Exchange system can not STARTTLS.
