How to setup an SSL Dovecot mail server

Question: How do I setup Dovecot to use IMAPS and POP3S with Postfix certificates?

Answer: Dovecot is a free and open source IMAP and POP3 mail server. It is used for receiving incoming mail and works in conjunction with Postfix, which handles sending and delivery. Dovecot runs on all Linux and Unix-like operating systems and is available in most distribution repositories. Some may even have it installed by default. Follow these simple steps to setup SSL:

Enable POP3S and IMAPS by editing the configuration file /etc/dovecot.conf. If they are enabled, the protocols setting will look like this:

protocols = imaps pop3s

Next you must set PEM encoded X.509 SSL/TLS certificate and private key. They’re opened before dropping root privileges, so keep the key file unreadable by anyone but root (see how create certificate CSR and configure certificates for Postfix):

ssl_cert_file = /etc/postfix/ssl/smtp.theos.in.crt
ssl_key_file = /etc/postfix/ssl/smtp.theos.in.key

If key file is password protected, give the password using ssl_key_password directive:
ssl_key_password = myPassword

Save and close the file. Restart Dovecot server:
# /etc/init.d/dovecot restart

Source: nixCraft