SPF, which is an abbreviation for Sender Policy Framework, is a verification system that is aimed at preventing the so-called email forging. Essentially, this means sending some message from one e-mail address and making it look like it’s sent from another one with the objective to scam in some way the person receiving it. In case the SPF protection is active for a domain name, a record which contains all mail servers authorized to email messages with addresses in the domain is generated. The record is saved on all of the DNS servers that route the Internet traffic all over the world, so they all will identify if an e-mail message comes from a trustworthy server or not. The check is performed at the first server where the email goes through and in the first case the e-mail message is forwarded, whereas in the second it is removed and it never gets to the intended recipient. Using SPF records for your domains will stop all unauthorized people from making use of your emails for harmful objectives.