SPF, which abbreviates Sender Policy Framework, is a verification system that is aimed at protecting against the so-called e-mail forging. In simple terms, this indicates sending some message from one e-mail address and making it look like it’s sent from another one with the idea to scam in some manner the person getting it. In the event that the SPF protection is activated for a domain, a record which includes all mail servers authorized to send messages with addresses in the domain is created. The record is stored on all of the DNS servers that route the web traffic around the world, thus they all will recognize if an e-mail 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 email message is forwarded, and in the second one it is discarded and it never gets to the intended recipient. Applying SPF records for your domains will prevent all unwanted people from making use of your emails for malicious purposes.