smtp-postfix.md

Config SMTP Postfix (DEBIAN+SENDGRID)

Enable PHP Mail

1. All updates installed:

sudo apt update

2. Install the sendmail package:

sudo apt-get install sendmail

3. Configure sendmail: You need to choose Yes to every question or otherwise configure it as you see fit.

sudo sendmailconfig

4. Edit hosts file

sudo vim /etc/hosts

• NOTE: You would define 127.0.0.1 my_ip localhost myhostname eg:

127.0.0.1   172.18.0.6  localhost   65e8408b426c5

5. Define your path mail at php.ini

• Get your php.ini path

php -i | grep "Loaded Configuration File"

• Edit your php.ini

vi /usr/local/etc/php/php.ini

sendmail_path= /usr/sbin/sendmail -t -i

6. Make sure the libsasl2-modules package is installed and up to date:

sudo apt-get install libsasl2-modules

Installing Postfix

1. Install Postfix with the following command:

sudo apt-get install postfix

• During the installation, a prompt will appear asking for your General type of mail configuration. Select Internet Site.

• Enter the fully qualified name of your domain, fqdn.example.com.

2. Find your Postfix config file, typically /etc/postfix/main.cf, and add the following:

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_sasl_tls_security_options = noanonymous
smtp_tls_security_level = encrypt
header_size_limit = 4096000
relayhost = [smtp.sendgrid.net]:587

3. Now you need to specify your credentials (optionally, use apikey as username and an API Key as password) in the separate file /etc/postfix/sasl_passwd (you'll likely need to create it):

[smtp.sendgrid.net]:587 yourSendGridUsername:yourSendGridPassword

• If you will use the API access then you need take this format

[smtp.sendgrid.net]:587 apikey:YOUR_API_KEY_HERE

• Would look like this

root@honVm:~# cat /etc/postfix/sasl_passwd
[smtp.sendgrid.net]:587 apikey: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

4. Next, make sure the file has restricted read and write access only for root, and use the postmap command to update Postfix's hashtables to use this new file:

sudo chmod 600 /etc/postfix/sasl_passwd
sudo postmap /etc/postfix/sasl_passwd

5. Restart Postfix:

sudo service postfix restart

Testing

The fastest way to test your configuration is to send an email to any unrelated email address, using the mail command:

echo "body of your email" | mail -s "This is a Subject" -a "From: [email protected]" [email protected]

Or create a file php with mail() function and run.

<?php 
   mail('[email protected]', 'test', 'you done that');
   echo 'ok';
?>

Note

If you restart the service again with another access then is possible you have this message:

[....] Starting Postfix Mail Transport Agent: postfixpostfix/postfix-script: fatal: the Postfix mail system is already running
 failed!

• Cause of the problem

Maybe it's postfix. The last time you forced the shutdown, you did not delete the lock itself. Lock exists at startup and cannot be run.

• Solution

The 1.Postfix master PID file (that is, the lock) also exists under the /var/spool/postfix/pid directory. Enter the directory to delete the file:

sudo ls /var/spool/postfix/pid
sudo rm /var/spool/postfix/pid/master.pid
sudo service postfix restart

Listo!