Outgoing mail via gmail

	WARNING
	This is recommended only for advanced users, proceed with caution.

This tutorial is now available as the Amahi Post Mail Relay application.

This can be used to send mails from your Amahi 7 or greater (Fedora 19 or greater) HDA and to receive system emails. To receive emails meant for the root user, you have to Forward System Emails after finishing this tutorial. You also might want to take a look at Masquerade email address as well.

REF: Postfix SMTP relay to SMTP gmail.com

• First of all, install postfix and remove sendmail:
  

yum -y install postfix mailx
yum -y remove sendmail

• Add the following to the bottom of the file /etc/postfix/main.cf. You do not need to change anything else in it, as the last setting for any option is the one that is saved.

####Gmail SMTP Relay
#TLS parameters
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache
smtp_tls_note_starttls_offer = yes
smtp_tls_policy_maps = hash:/etc/postfix/tls_policy
 
#Relay host configuration
relayhost = [smtp.gmail.com]:587
 
#SASL Configuration
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_sasl_mechanism_filter = plain
smtp_sasl_tls_security_options = noanonymous

• Create /etc/postfix/sasl_passwd file with your Gmail login credentials that looks like below:

[smtp.gmail.com]:587 user@gmail.com:Password

NOTE: Change user to your username and password to your gmail crredentials.

• Build the password database:
  

postmap hash:/etc/postfix/sasl_passwd

• Create /etc/postfix/tls_policy file that looks like below:

[smtp.gmail.com]:587 encrypt

• Build the policy database:
  

postmap /etc/postfix/tls_policy

• Protect the files with your Gmail login data:

chmod 600 /etc/postfix/sasl_passwd
chmod 600 /etc/postfix/sasl_passwd.db
chmod 600 /etc/postfix/tls_policy
chmod 600 /etc/postfix/tls_policy.db

• Restart Postfix:

systemctl restart postfix.service

• Set Postifx to start on boot:

systemctl enable postfix.service

• Now try sending a mail, it should reach your Gmail account:

echo test 1 2 | mail -s "Test mail" user@gmail.com

NOTE: Some ISPs will block emails sent using this method. Looking for a work around.

Troubleshooting

• If you get the message " warning: SASL authentication failure: No worthy mechs found", install this package.

yum install cyrus-sasl{,-plain}

Restart Postfix

systemctl restart postfix

• Receive the following message:

connect to smtp.gmail.com[2607:f8b0:400e:c05::6d]:587: Network is unreachable

To correct this problem, change /etc/postfix/main.cf as follows:

inet_protocol = ipv4

Restart postfix

systemctl reload postfix

See also:
Forward System Emails
Monitor System Logs via E-mail