The Postfix SMTP server has been update to support SMTPS and STARTTLS to create encryption tunnels and SMTP AUTH to allow mail clients to authenticate with the server. This authentication allows the server to know that the client is allowed to relay mail through Employees.Org. We have been using pop-before-smtp, which has not been 100% reliable, especially with newer versions of Thunderbird. This new system is standards based and should work with any decent mail client from this point forward. See the SSL Howto for information on how to configure for outgoing SMTPS.