SPF, which is an abbreviation for Sender Policy Framework, is a validation system that aims at preventing the so-called e-mail faking. In simple terms, this means sending some message from one email and making it appear to be sent from a different one with the objective to scam in some way the person getting it. In case the SPF protection is activated for a domain, a record which contains all the mail servers authorized to send messages with addresses in the domain is made. The record is saved on all the DNS servers that direct the web traffic globally, so they all can identify if an email message originates from an authentic server or not. The verification is done at the very first server where the email goes through and in the first case the e-mail message is forwarded, whereas in the second it's discarded and it never reaches the supposed recipient. Employing SPF records for your domains will stop all unauthorized people from using your emails for harmful objectives.