SPF, which is short for Sender Policy Framework, is an email security system, which is employed to confirm if an email message was sent by a certified server. Employing SPF protection for a particular domain will stop the counterfeiting of email addresses made with the domain. In simple words: activating this feature for a domain makes a special record in the Domain Name System (DNS) which includes the IP of the servers that are permitted to send emails from mail boxes under the domain. Once this record propagates worldwide, it will exist on all DNS servers that route the Internet traffic. Any time an email message is sent, the initial DNS server it uses verifies if it comes from an accredited server. In the event it does, it's sent to the destination address, yet if it doesn't originate from a server indexed in the SPF record for the domain, it is discarded. Thus nobody will be able to mask an e-mail address and make it look as if you're distributing spam. This approach is also referred to as email spoofing.