<https://forums.hak5.org/topic/26861-sendmail-open-relay/#comment-205265>
<http://schema.org/text>
"I'm not sure how this would work with authenticated smtp hosts, most common emails (gmail, hotmail, yahoo etc) all require authentication on the smtp server side and most of them utilize some form of encryption aswell. I'm not ruling it out, I just think it will be quite difficult to implement. "
<https://forums.hak5.org/topic/26861-sendmail-open-relay/>