SPF, which is an abbreviation for Sender Policy Framework, is a certification system that aims at stopping the so-called e-mail faking. Basically, this indicates sending some message from one e-mail and making it look like it’s sent from a different one with the purpose to scam in some way the individual opening it. In case the SPF protection is running for a domain, a record that contains all of the 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 Internet traffic worldwide, so they all will recognize whether an email message originates from a trustworthy server or not. The verification is conducted at the very first server where the e-mail goes through and in the first case the e-mail message is forwarded, and in the second one it is discarded and it never reaches the intended recipient. Using SPF records for your domain names will prevent any unwanted people from making use of your email addresses for harmful purposes.