SPF, which abbreviates Sender Policy Framework, is a certification system that is aimed at blocking the so-called email faking. In simple terms, this indicates sending some message from one email and making it seem to be sent from a different one with the purpose to scam in some way the individual opening it. When the SPF protection is running for a domain name, a record which contains all the mail servers authorized to email messages with addresses under the domain is made. The record is saved on all the DNS servers that direct the Internet traffic around the world, thus they all can identify whether an email message comes 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 email message is forwarded, whereas in the second it is discarded and it never gets to the supposed recipient. Applying SPF records for your domains will prevent any unauthorized people from making use of your emails for malicious objectives.