Email server on Mac Mini

I set up postfix email server on my Mac mini some time ago but I recently wiped & reinstalled El Capitan (OS X 10.11.1) on that machine when I replaced the HDD with a SSD, so here’s how I did it. I’ve italicised where you need to enter your own specific info. The main sources for my info were:

• Using MacOSX Lion command line mail with Gmail as SMTP
• Send Email on OS X Lion through GMail
• relay server requires authentication
• How to generate an App password
• Rogers email settings

Note: this configuration has evolved over a few years, so there may be some redundant settings.

• Append to /etc/postfix/main.cf
  relayhost = [smtp.gmail.com]:587
  myhostname = $HOSTNAME
  mydomain = yourDomainName
  myorigin = $mydomain
  smtp_use_tls = yes
  smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
  smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
  smtp_tls_note_starttls_offer = yes
  smtp_tls_security_level=encrypt
  smtp_tls_CApath = /etc/certificates
  smtp_sasl_auth_enable = yes
  smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
  smtp_sasl_security_options = noanonymous
  smtp_sasl_mechanism_filter = plain
  smtp_sasl_tls_security_options = noanonymous

• vi /etc/postfix/smtp_tls_sites
  smtp.broadband.rogers.com MAY

• vi /etc/postfix/tls_policy
  [smtp.gmail.com]:587 encrypt

• vi /etc/postfix/sasl_passwd
  [smtp.gmail.com]:587 yourEmailAddress@gmail.com:googleAppPassword

• chmod 600 /etc/postfix/sasl_passwd
• postmap /etc/postfix/sasl_passwd
• postmap /etc/postfix/smtp_tls_sites
• % sudo openssl s_client -starttls smtp -crlf -connect smtp.broadband.rogers.com:587 -showcerts < /dev/null | sed -n '/-BEGIN /,/-END /p' | sudo sh -c 'cat > /etc/certificates/relayhost.pem’
• % sudo postfix start
• % date | mail yourEmailAddress
• % mailq

One problem I haven’t yet resolved is having postfix start automatically after booting OS X. I had this working with previous versions of OS X but El Capitan introduced System Integrity Protection which means I can’t easily update the postfix property list (plist) in /System/Library/LaunchDaemons.