SPF, which abbreviates Sender Policy Framework, is a verification system that is aimed at stopping the so-called e-mail forging. Basically, this indicates sending a message from one email and making it look like it’s sent from a different one with the purpose to scam in some way the individual opening it. In the event that the SPF protection is running for a domain, a record which includes all mail servers authorized to send messages with addresses in the domain is created. The record is saved on all of the DNS servers that direct the web traffic internationally, thus they all can recognize whether an e-mail message originates from a legitimate server or not. The check is conducted at the first server where the e-mail goes through and in the first case the message is forwarded, and in the second one it's removed and it never reaches its intended recipient. Employing SPF records for your domain names will stop all unauthorized people from using your emails for malicious purposes.