How to Enable User Authentication for a Postfix SMTP Server with SASL

Every mail server administrator dreads his or her server becoming compromised by spammers. A lot of effort, time and even money is spent on securing mail servers and making sure that the servers do not become open relay. This tutorial will focus on setting up a Postfix SMTP server to use Dovecot SASL for user authentication. Simple Authentication and Security Layer (SASL) is a framework that can be used by many connection-oriented Internet protocols for securing data, servers and users. With SASL enabled, Postfix will not accept any incoming SMTP connections without proper authentication.