SPF, which means Sender Policy Framework, is an email security system, that is employed to confirm if an email message was sent by a licensed server. Employing SPF protection for a domain name will stop the faking of emails made with the domain. In layman's terms: enabling this function for a domain name creates a special record in the Domain Name System (DNS) that contains the IP of the servers that are allowed to send e-mails from mailboxes under the domain. The moment this record propagates globally, it will exist on all of the DNS servers that direct the Internet traffic. Whenever some e-mail message is sent, the initial DNS server it uses verifies whether it comes from an accredited server. When it does, it's sent to the destination address, however when it does not originate from a server listed in the SPF record for the particular domain, it is discarded. In this way nobody will be able to mask an e-mail address to make it look as if you are e-mailing spam. This approach is also called email spoofing.