SPF, which abbreviates Sender Policy Framework, is a certification system that aims at protecting against the so-called email counterfeiting. In simple terms, it indicates sending some message from one email address and making it seem to be sent from another with the objective to scam in some way the person opening it. In case the SPF protection is running for a domain name, a record which includes all of the mail servers authorized to email messages with addresses within the domain is generated. The record is stored on all DNS servers that route the Internet traffic across the globe, therefore they all can identify whether an e-mail message originates from a valid server or not. The check is performed at the very first server where the e-mail goes through and in the first case the e-mail message is forwarded, and in the second one it is discarded and it never gets to the supposed recipient. Employing SPF records for your domain names will prevent any unauthorized people from making use of your email addresses for harmful objectives.