SPF, which is an abbreviation for Sender Policy Framework, is a certification system that is aimed at blocking the so-called email faking. In simple terms, this means sending some message from one e-mail and making it seem to be sent from another with the idea to scam in some manner the person opening it. In case the SPF protection is running for a domain name, a record that contains all of the mail servers authorized to email messages with addresses within the domain is made. The record is placed on all DNS servers that direct the web traffic all over the world, thus they all can identify if an email message originates from a trustworthy server or not. The verification is done at the first server where the email goes through and in the first case the message is forwarded, and in the second it is discarded and it never gets to its intended recipient. Employing SPF records for your domains will stop all unauthorized people from making use of your emails for harmful purposes.