SPF, which is an abbreviation for Sender Policy Framework, is an authentication system that aims at protecting against the so-called e-mail forging. Basically, this means sending some message from one e-mail and making it look like it’s sent from another one with the objective to scam in some manner the individual opening it. In the event that the SPF protection is running for a domain, a record that contains all of the mail servers authorized to send messages with addresses within the domain is made. The record is placed on all DNS servers that direct the Internet traffic around the world, so they all will identify whether an email message comes from an authentic server or not. The verification is conducted at the very first server where the e-mail goes through and in the first case the email message is forwarded, whereas in the second it is discarded and it never gets to the intended recipient. Using SPF records for your domains will stop any unwanted people from making use of your emails for harmful purposes.