SSMTP
From Vague Hope Wiki
Set up
sudo aptitude install ssmtp sudo vi /etc/ssmtp/ssmtp.conf root=username@gmail.com mailhub=smtp.gmail.com:587 hostname=username@gmail.com UseSTARTTLS=YES AuthUser=username AuthPass=password FromLineOverride=yes sudo chmod 600 /etc/ssmtp/ssmtp.conf sudo vi /etc/ssmtp/revaliases root:machine-name:smtp.gmail.com
Testing
echo "Test message from Linux server using ssmtp" | sudo ssmtp -F Hostname user@example.com