Outgoing mail via gmail

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

This can be used to send mails from your Amahi 7/8 (Fedora 19/21) 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