SPF, which abbreviates Sender Policy Framework, is a validation system that is aimed at protecting against the so-called e-mail counterfeiting. Essentially, this indicates sending a message from one email address and making it look like it’s sent from another one with the objective to scam in some way the person getting it. When the SPF protection is activated for a domain, a record that contains all mail servers authorized to email messages with addresses in the domain is made. The record is placed on all the DNS servers that route the web traffic internationally, so that they all can identify whether an email 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 message is forwarded, and in the second one it's discarded and it never gets to the intended recipient. Applying SPF records for your domain names will stop any unwanted people from using your emails for harmful objectives.