SPF, which means Sender Policy Framework, is an e-mail safety system, which is designed to validate whether an e-mail message is sent by an official server. Using SPF protection for a domain name will prevent the faking of email addresses generated with the domain. In layman's terms: enabling this feature for a domain name creates a specific record in the Domain Name System (DNS) which includes the IP addresses of the servers which are permitted to send emails from mailboxes under the domain. Once this record propagates worldwide, it will exist on all DNS servers that route the Internet traffic. Every time a new email message is sent, the first DNS server it goes through verifies whether it originates 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's rejected. In this way nobody will mask an e-mail address to make it appear as if you're e-mailing spam messages. This technique is also known as email spoofing.