SPF, which abbreviates Sender Policy Framework, is an authentication system that is aimed at protecting against the so-called email counterfeiting. Essentially, it indicates sending some message from one email address and making it look like it’s sent from another with the purpose to scam in some way the person getting it. If the SPF protection is activated for a domain, a record that contains all the mail servers authorized to email messages with addresses part of the domain is created. The record is stored on all DNS servers that direct the Internet traffic across the globe, so they all will recognize if an email message originates from a legitimate server or not. The check is done at the first server where the e-mail goes through and in the first case the email message is forwarded, whereas in the second it is discarded and it never gets to the intended recipient. Employing SPF records for your domains will stop all unwanted people from using your emails for harmful purposes.