Postfix gmail relay OS X 10.9 Maverics

gmail relay postfix

/etc/postfix/main.cf:
  # Use gmail as relayhost
  relayhost = [smtp.gmail.com]:587

  # Map outbound users from local user@host.local to real mail users
  smtp_generic_maps = hash:/etc/postfix/generic
 
  # Configure authentication for gmail's TLS requirements
  smtp_tls_loglevel=1
  smtp_tls_security_level=encrypt
  smtp_sasl_auth_enable=yes
  smtp_sasl_password_maps=hash:/etc/postfix/passwd
  smtp_sasl_security_options = noanonymous

  # Most gmail relay online resources does not mention this. I kept getting 
  # "530-5.5.1 Authentication Required" failures from gmail without this line.
  # It's probably some defaults in OS X 10.9 Maverics that is different.
  smtp_sasl_mechanism_filter = plain

/etc/postfix/generic:
  # Change for your user and/or add others
  user@host.local         external_user@mail_host
  
/etc/postfix/passwd:
  # Change for your user and/or add others
  [smtp.gmail.com]:587    user:pass
  
$:
  # Execute the following in a shell to activate generic and passwd
  sudo postmap /etc/postfix/generic
  sudo postmap /etc/postfix/passwd