SPF, which abbreviates Sender Policy Framework, is a certification system that is aimed at protecting against the so-called e-mail forging. In simple terms, this indicates sending a message from one email address 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 the event that the SPF protection is running for a domain, a record which includes all mail servers authorized to send messages with addresses in the domain is generated. The record is kept on all DNS servers that route the web traffic worldwide, so they all will recognize whether an email message originates from a trustworthy server or not. The verification is done at the first server where the email goes through and in the first case the email message is forwarded, but in the second it is discarded and it never gets to its intended recipient. Applying SPF records for your domains will stop any unauthorized people from using your emails for harmful objectives.