SPF, which abbreviates Sender Policy Framework, is a validation system that aims at preventing the so-called e-mail forging. In simple terms, this means sending a message from one e-mail address and making it look like it’s sent from another one with the purpose to scam in some way the person opening it. When the SPF protection is active for a domain, a record that contains all mail servers authorized to send messages with addresses within the domain is created. The record is saved on all the DNS servers that route the Internet traffic across the globe, so that they all will identify if an e-mail message originates from a valid server or not. The check is conducted at the very first server where the email goes through and in the first case the email message is forwarded, but in the second one it is discarded and it never gets to the intended recipient. Using SPF records for your domain names will prevent any unauthorized people from making use of your email addresses for malicious objectives.