SPF, which is an abbreviation for Sender Policy Framework, is a validation system that is aimed at protecting against the so-called e-mail faking. Basically, it indicates sending some message from one e-mail and making it seem to be sent from another with the purpose to scam in some way the individual getting it. If the SPF protection is running for a domain name, a record that contains all of the mail servers authorized to email messages with addresses within the domain is generated. The record is kept on all of the DNS servers that route the Internet traffic globally, therefore they all will identify whether an e-mail message comes from an authentic server or not. The check 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 its intended recipient. Using SPF records for your domain names will stop any unauthorized people from making use of your emails for malicious purposes.