Postfix Gmail relay on macOS Sierra & macOSHigh Sierra

postfix-gmail-macos.md

Postfix Gmail relay on macOS Sierra & macOSHigh Sierra

1 - Create a file to store our credentials:

sudo vim /etc/postfix/sasl_passwd

2 - Add something like this:

smtp.gmail.com:587 username@gmail.com:password

3 - Now run:

sudo postmap /etc/postfix/sasl_passwd

4 - Prepare the postfix main config file:

sudo vim /etc/postfix/main.cf

5 - Add/update these lines:

relayhost = smtp.gmail.com:587
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_use_tls = yes
smtp_tls_security_level = encrypt
tls_random_source = dev:/dev/urandom
smtp_sasl_security_options = noanonymous
smtp_always_send_ehlo = yes
smtp_sasl_mechanism_filter = plain

6 - Postfix service:

Check postfix status:

sudo postfix status

• If postfix is not running, start the service:

  postfix/postfix-script: the Postfix mail system is not running
  

  sudo postfix start
  

  postfix/postfix-script: starting the Postfix mail system
  

• If postfix is running, reload the service:

  postfix/postfix-script: the Postfix mail system is running: PID: XXXX
  

  sudo postfix reload
  

  postfix/postfix-script: refreshing the Postfix mail system
  

7 - Testing:

date | mail -s testing your_email@gmail.com

8 - Check the queue for any errors:

mailq

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Useful:

• To clear the mail queue: sudo postsuper -d ALL

Troubleshoot problems:

• If you receive a message like (TLS is required, but our TLS engine is unavailable) enable tls:

  sudo postfix tls enable-client
  

Turn on less secure apps

In Gmail we must switch on the option “Access for less secure apps“, otherwise we will get the error: SASL authentication failed https://support.google.com/mail/answer/7126229?p=BadCredentials&rd=2#cantsignin