I’ve been using “mail-stack-delivery” for several years now. It’s the easiest way to get a secure mail server going in minutes.
Another option for configuring Postfix for SMTP-AUTH is using the mail-stack-delivery package (previously packaged as dovecot-postfix). This package will install Dovecot and configure Postfix to use it for both SASL authentication and as a Mail Delivery Agent (MDA). The package also configures Dovecot for IMAP, IMAPS, POP3, and POP3S.
You may or may not want to run IMAP, IMAPS, POP3, or POP3S on your mail server. For example, if you are configuring your server to be a mail gateway, spam/virus filter, etc. If this is the case it may be easier to use the above commands to configure Postfix for SMTP-AUTH.
To install the package, from a terminal prompt enter:
sudo apt-get install mail-stack-delivery
You should now have a working mail server, but there are a few options that you may wish to further customize. For example, the package uses the certificate and key from the ssl-cert package, and in a production environment you should use a certificate and key generated for the host. See Certificates for more details.
Once you have a customized certificate and key for the host, change the following options in /etc/postfix/main.cf:
smtpd_tls_cert_file = /etc/ssl/certs/ssl-mail.pem smtpd_tls_key_file = /etc/ssl/private/ssl-mail.key
Then restart Postfix:
sudo service postfix restart