Setup PHP to use Postfix to send emails

Postfix is a Message Transfer Agent implementation, basically an email server to send and recieve emails, and since PHP doesn’t include an SMTP implementation it needs an external server to do that if you plan on using the internal mail function.

While it is not encouraged to install and use your own email server, you might need one for testing purposes or in situations where you have to use PHP’s internal mail function, so here is how I installed Postfix on Ubuntu and set it up to send emails using PHP’s mail function.

First you’ll install postfix using the following command:

sudo apt-get install postfix

It will prompt you to enter a FQDN which is your top domain name e.g. example.org, It’s well explained in the installation process so it shouldn’t be a problem.

To test your installation enter this command sendmail -tif from@example.org to@example.com Where from@example.com is the email you’re sending from and to@example.com is the email you’re sending to. Write a message then press Ctrl+d, you should now find your message in to@example.com inbox or spam folders.

Now edit your proper php.ini file for me it was in /etc/php/7.0/fpm/php.ini and edit sendmail_path entry to be:

sendmail_path = "sendmail -tif from@example.org"

Again from@example.com will be the default email address used as the from email.

Now reload Postfix and your server then you should be able to send emails using mail function from your server.

This serverfault answer helped a lot:

https://serverfault.com/a/289290

And as a bonus, here is how to configure Postfix to use sendgrid as a relay host.

https://sendgrid.com/docs/Integrate/Mail_Servers/postfix.html