Today’s ISP environment requires authenticated SMTP to be able to send emails. As a policy, authenticated SMTP helps cut down on folks sending SPAM and allows the ISP to track which account is sending what type of email content for further demographic study. While authenticated SMTP is good for the ISP, it is not a configuration supported out of the box by most Linux distributions. This means that all those system emails and log reports emailed by root never make it anywhere anymore.The solution is to configure your Linux distribution to send authenticated SMTP. My local ISP requires authenticated SMTP and here is how I got Exim4 to work for me on Ubuntu LTS 8.04. Read complete article..