I use Postfix to relay system messages (e.g. a botched cronjob) over SSL to my Gmail account. These messages are otherwise “lost” because the email is being sent to a dormant mail transfer agent on my Mac. There’s way more that you can do with Postfix, but I’ll just cover the setup I did for my needs. 1. Create the Simple Authentication and Security Layer (SASL) password file. sudo vi /etc/postfix