SMTP relay

Еще один рецепт конфигурации Postfix SMTP на отправку всей почты через Gmail.

If you want to use a Gmail account as a free SMTP server on your Ubuntu-Linux server, you will find this article useful....

sudo apt-get install postfix mailutils libsasl2-2 ca-certificates libsasl2-modules

...

vim /etc/postfix/main.cf

relayhost = [smtp.gmail.com]:587

smtp_sasl_auth_enable = yes

smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd

smtp_sasl_security_options = noanonymous

smtp_tls_CAfile = /etc/postfix/cacert.pem

smtp_use_tls = yes

…

vim /etc/postfix/sasl_passwd

[smtp.gmail.com]:587 USERNAME@gmail.com:PASSWORD

…

sudo chmod 400 /etc/postfix/sasl_passwd

sudo postmap /etc/postfix/sasl_passwd

...

cat /etc/ssl/certs/Thawte_Premium_Server_CA.pem | sudo tee -a /etc/postfix/cacert.pem

...

sudo /etc/init.d/postfix reload

echo "Test mail from postfix" | mail -s "Test Postfix" you@example.com

подробности здесь: https://rtcamp.com/tutorials/linux/ubuntu-postfix-gmail-smtp/

original post http://vasnake.blogspot.com/2014/03/smtp-relay.html