Send emails through Mailgun SMTP on CentOS 7

Install the dependencies:

yum install postfix cyrus-sasl-plain cyrus-sasl-md5 mailx -y

In /etc/postfix/, append the following to the end of file:

relayhost =
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_sasl_mechanism_filter = AUTH LOGIN

Run the following to configure the authentication details:

echo ' postmaster@<mailgun_host>:<mailgun_credentials>' > /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd
postmap /etc/postfix/sasl_passwd
systemctl restart postfix

And finally test it out!

mail -s "Test mail" <<< "A test message using Mailgun"
cat /var/log/maillog

References #