SPF, which abbreviates Sender Policy Framework, is a certification system that aims at stopping the so-called e-mail faking. Basically, this means sending some message from one e-mail address and making it seem to be sent from another one with the purpose to scam in some manner the individual getting it. If the SPF protection is activated for a domain, a record which contains all of the mail servers authorized to email messages with addresses within the domain is created. The record is placed on all the DNS servers that route the web traffic all over the world, so they all will recognize if an email message originates from an authentic server or not. The verification is performed 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 one it is removed and it never reaches the intended recipient. Applying SPF records for your domain names will prevent all unwanted people from making use of your emails for harmful purposes.