* [[https://help.ubuntu.com/community/PostfixVirtualMailBoxClamSmtpHowto]]
  * [[https://www.exratione.com/2016/05/a-mailserver-on-ubuntu-16-04-postfix-dovecot-mysql/]]

==== Postfix SMTP & Dovecot SASL ====

  /etc/postfix/main.cf

  smtpd_sasl_auth_enable = yes
  smtpd_sasl_security_options = noplaintext,noanonymous
  smtpd_sasl_tls_security_options = noanonymous
  smtpd_sasl_path = private/auth
  smtpd_sasl_type = dovecot
  queue_directory = /var/spool/postfix
  
  smtpd_tls_cert_file = /etc/apache2/ssl/valami.hu/cert.pem
  smtpd_tls_key_file = /etc/apache2/ssl/valami.hu/key.pem
  smtpd_tls_security_level = may
  smtpd_tls_auth_only = yes
  smtpd_tls_mandatory_ciphers = high
  smtpd_tls_mandatory_exclude_ciphers = aNULL,MD5
  smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3
  smtpd_starttls_timeout = 300s

  /etc/dovecot/dovecot.conf

  service auth {
    executable = /usr/lib/dovecot/auth
    user = root
    unix_listener auth-userdb {
      #mode = 0666
      #user =
      #group =
    }
  
    # Postfix smtp-auth
    unix_listener /var/spool/postfix/private/auth {
      mode = 0666
      user = postfix
      group = postfix
    }
  }