Scenario: You’re working from a home ISP connection or traveling, but would like to have your Mac send emails for jobs that have completed or other misc. notices without having to reconfigure each time. Since many ISPs block outbound SMTP servers on standard ports, forcing you to use their servers, this can be a headache.
I decided to use Google’s App/SMTP server to get around this as it uses a non-standard SMTP port and requires authentication. There are tons of guides on how to do this online, but none of them seemed to work for my setup. So, without further ado, here’s how to setup your mac, leveraging Google servers as a relay via Postfix:
First edit /etc/postfix/main.cf:
$ sudo vi /etc/postfix/main.cf
Add this to the end of the file:
myhostname = _HOSTNAME_ relayhost = [smtp.gmail.com]:587 smtp_sasl_auth_enable = yes smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd smtp_sasl_security_options = noanonymous smtp_use_tls = yes smtp_sasl_mechanism_filter = plain
Also, edit this line and adjust it to your preference, default is 1MB. I changed mine to 100MB since I send large logfiles:
message_size_limit = 100000000
Edit/create /etc/postfix/sasl_passwd. You’ll need to login to your Google account and create an app password. Spaces from this password are not required in this file:
$ sudo vi/etc/postfix/sasl_passwd
The format of the file should look like this:
Modify the permissions of the password file to protect the contents:
$ sudo chmod 600 /etc/postfix/sasl_passwd
Next, hash the password. This will create a sasl_passwd.db file:
$ sudo postmap /etc/postfix/sasl_passwd
Restart the postfix services for the change to take effect:
$ sudo launchctl stop org.postfix.master $ sudo launchctl start org.postfix.master
And finally, run a test:
$ date | mail -s "test 1 again” email@example.com
Check the queue for errors. Should report “Mail queue is empty” if everything went well.
$ date && postqueue -p
If you received the message, then you’re all set. Your OS can now send mail from anywhere in the world without having to worry about reconfiguring for local SMTP servers due to blocked ports.