To complete the setup, save main.cf and restart the Postfix server. Send a test mail and view the log file /var/log/mail. You should see the mail relay through your mail hub. Check the log file on the mail hub to see if the mail was successfully sent. If not, check the system log file /var/log/messages. Postfix will log SSL transactions in the system log. If a mail cannot be sent, it can be diagnosed via the system log file. For more information about Postfix, take a look at the man pages. The Postfix man pages are some of the best I have seen. They are clear and concise, making a sys admin's job a lot easier.