[ Thanks to Andrew
Weber for this link. ]
“Now there is one problem you need to recognize. The mail that
you send and retrieve from your mail server is plain text but is
protected because of the security you have set up. However, when
you send mail, once it leaves your mail server it is not protected
and travels to the next mail server in plain text in which it could
be captured and read. If you want to protect the contents of your
mail you must use encryption to protect your mail from source to
destination. Meaning, you encrypt it and someone on the other end
must unencrypt with keys that you need to provide them. The real
advantage of protecting your connections when you are sending and
retrieving is that your passwords are protected to and from your
mail server.”