title: How does SPF/DKIM "auto authentication" work on mail chimp?
body: <p>Mail chimp offers three levels of authentication when doing email campaigns.</p>
  
  <ol>
  <li>Manual Authentication</li>
  <li>No Authentication</li>
  <li>Auto Authentication</li>
  </ol>
  
  <p>From what I understand Manual Authentication is when you set up your own SPF/DKIM records on your DNS.</p>
  
  <p>No Authentication is when no body sets up anything, and I'm pretty sure deliverability goes way down.</p>
  
  <p>The Auto Authentication is what I am curious about.  All they do is require the person sending the email to approve that their email address is ok to send from with a validation email.  I'm done research, and I can't figure out how mail chimp and other people do this auto-authentication.</p>
  
  <p>Is there any service out there, or would we have to set up our own email servers to accomplish something like this.</p>
  
  <p>Also what kind of effect on deliverability is the "auto" authentication.</p>