SPF, which is an abbreviation for Sender Policy Framework, is an authentication system that aims at preventing the so-called email faking. Essentially, it indicates sending a message from one email and making it look like it’s sent from another one with the purpose to scam in some manner the person opening it. When the SPF protection is active for a domain, a record which includes all 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 internationally, therefore they all will recognize whether an e-mail message originates from a valid server or not. The check is conducted at the first server where the e-mail goes through and in the first case the email message is forwarded, whereas in the second one it is removed and it never reaches the supposed recipient. Using SPF records for your domain names will stop any unwanted people from making use of your emails for malicious purposes.