SPF, which is an abbreviation for Sender Policy Framework, is a verification system that aims at stopping the so-called e-mail faking. In simple terms, this indicates sending some message from one email and making it look like it’s sent from a different one with the idea to scam in some manner the individual opening it. In the event that the SPF protection is activated for a domain name, a record which has all of the mail servers authorized to send messages with addresses in the domain is made. The record is placed on all the DNS servers that route the web traffic internationally, so they all will identify whether an e-mail message originates from a legitimate server or not. The verification is done at the first server where the e-mail goes through and in the first case the email message is forwarded, but in the second one it's removed and it never reaches the intended recipient. Applying SPF records for your domains will prevent all unwanted people from making use of your email addresses for malicious objectives.