Postfix Configuration macOS

Postfix Configuration macOS

This is a little step-by-step guide which worked for me to send emails from macOS on my local machine.

Step 1 – sasl_passwd file

Create a SASL (a Simple Authentication and Security Layer) password file:

> sudo vi /etc/postfix/sasl_passwd

The file contains only a single line consisting of the following data:

[mailserver]:[port] []:[password]

You have to replace [mailserver], [] as well as [password] with the actual data. You might be able to skip the :[port] part.
For example:

Step 2 – postfix lookup

Create a postfix lookup for the SASL password file, this is done by executing the following command:

> sudo postmap /etc/postfix/sasl_passwd

You could test this configuration by running:

> postmap -q [mailserver] hash:/etc/postfix/sasl_passwd

This should return your configuration data, continuing the example from above:

> postmap -q hash:/etc/postfix/sasl_passwd

Step 3 – main configuration

Now you have to adapt the postfix main configuration file I recommend backing it up before you start editing it.

> sudo vi /etc/postfix/

Some of these settings might be set already, just enter the missing parts at the bottom of the file:

mail_owner = _postfix
setgid_group = _postdrop

# specifix configuration
myhostname = <>
relayhost = <mailserver>:<port>
smtpd_sender_restrictions = permit_inet_interfaces

# enable SASL
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options =

# enable TLS
smtp_sasl_mechanism_filter = AUTH LOGIN

# what domains to receive mail for
mydestination =

Step 4 – (re)start postfix

Now you've to (re)start postfix in order to read in the current configuration:

> sudo postfix start
(or rather) sudo postfix reload

Step 5 – Testing

It's time to test the configuration by sending a test mail. You could do so by executing:

> date | mail -s testmail
> php -r "if (mail('', 'postfix test', date('D M d H:i:s T Y'))) { echo 'success'; }"

Step 6 – Mail Queue

From time to time it's quite useful to have a look at the mail queue:

> mailq

You could reset the mail queue manually by running:

> sudo postsuper -d ALL

Step 7 – Logging

/var/log/mail.log does not work since macOS Sierra. Apple uses a new log system and does not use the log files / asl any longer.
Now the logs are stored in memory or in a log db.

@see: Server 5.2 missing SMTP Logs

You can use the following command:

> log stream --predicate  '(process == "smtpd") || (process == "smtp")' --info  | grep "to=<"

You can also redirect the output directly into a file:

> log stream --predicate  '(process == "smtpd") || (process == "smtp")' --info > ~/mail.log