SPF, which abbreviates Sender Policy Framework, is an authentication system that is aimed at stopping the so-called e-mail forging. Basically, it indicates sending a message from one e-mail address and making it seem to be sent from a different one with the purpose to scam in some manner the person receiving it. When the SPF protection is running for a domain name, a record which includes all the mail servers authorized to send messages with addresses under the domain is created. The record is saved on all of the DNS servers that direct the web traffic all over the world, thus they all will identify whether an email message comes from a valid server or not. The check is conducted at the very first server where the e-mail goes through and in the first case the message is forwarded, while in the second it is removed and it never reaches the supposed recipient. Applying SPF records for your domains will prevent all unwanted people from making use of your emails for harmful objectives.