SPF, which is short for Sender Policy Framework, is an email security system, that is designed to confirm if an e-mail message was sent by a certified server. Employing SPF protection for a domain name will stop the forging of email addresses made with the domain. In layman's terms: enabling this attribute for a domain name generates a particular record in the Domain Name System (DNS) that contains the IP addresses of the servers that are permitted to send emails from mail boxes using the domain. When this record propagates worldwide, it will exist on all DNS servers that direct the Internet traffic. Every time an email message is sent, the first DNS server it goes through verifies whether it originates from an accredited server. When it does, it's forwarded to the destination address, however if it does not come from a server indexed in the SPF record for the domain, it's rejected. In this way nobody will mask an email address then make it look as if you're e-mailing spam. This technique is also known as email spoofing.