I'm building a mail server loosely based on the Debian Squeeze perfect server "how to". The primary mail components are Postfix and Courier, and Postfix is using Courier for user/password authorizations. For more detail please see http://www.howtoforge.com/forums/showthread.php?t=53595 The problem I have now is that the following things happen: * I can relay mail using SSL/TLS from a mail client, supplying my email address and password * I can send mail to user who are in the mailbox database provided the mail is relayed through a server that will not attempt an SSL connection to my mail server * Sending mail to one user through a relay that does try to use SSL results in the mail being rejected as no such user. The same mail can be sent successfully via a non-SSL relay. * Sending mail to another user through a relay that tries to use SSL results in the mail being accepted but not delivered. The same mail can be sent successfully via a non-SSL relay. What can I do to diagnose the problems?