https://en.wikipedia.org/wiki/DomainKeys_Identified_Mail
https://portal.smartertools.com/kb/a2754/set-up-dkim-and-domain-key.aspx
http://www.dkim.org/
Trouble logging in? Simply enter your email address OR username in order to reset your password.
For faster and more reliable delivery, add example@example.com to your trusted senders list in your email software.