===== Install and Configure Postfix To Be A Smart Host =====

  - Start with a fully updated and configured Ubuntu server.
  - Install Postfix<code>
sudo debconf-set-selections <<< "postfix postfix/mailname string `hostname -f`"
sudo debconf-set-selections <<< "postfix postfix/main_mailer_type string 'Internet Site'"
sudo apt-get -y install postfix
</code>
  - After installation is complete, type while replacing mydestination and mynetworks with the real values:<code>
sudo postconf -e 'mydestination = host.example.com'
sudo postconf -e 'mynetworks = 127.0.0.0/8 [::1]/128 192.168.0.1/32'
</code>