SPF, which is an abbreviation for Sender Policy Framework, is a validation system that aims at blocking the so-called email faking. Essentially, this means sending a message from one e-mail address and making it seem to be sent from another with the objective to scam in some way the individual receiving it. If the SPF protection is activated for a domain name, a record that includes all mail servers authorized to email messages with addresses part of the domain is made. The record is saved on all DNS servers that direct the Internet traffic all over the world, thus they all will recognize whether an e-mail message originates from a valid server or not. The verification is performed at the first server where the email goes through and in the first case the e-mail message is forwarded, but in the second one it is removed and it never reaches the intended recipient. Applying SPF records for your domains will prevent all unauthorized people from making use of your email addresses for harmful objectives.