SPF, which means Sender Policy Framework, is an e-mail protection system, which is designed to validate whether an e-mail message was sent by an official server. Using SPF protection for a domain name will stop the faking of email addresses generated with the domain. In simple words: enabling this attribute for a domain creates a special record in the Domain Name System (DNS) which contains the IP addresses of the servers which are permitted to send emails from mailboxes under the domain. As soon as this record propagates globally, it exists on all DNS servers that direct the Internet traffic. Any time an e-mail message is sent, the first DNS server it goes through verifies whether it originates from an official server. If it does, it is sent to the destination address, yet if it does not originate from a server indexed in the SPF record for the domain, it's discarded. In this way nobody can mask an e-mail address then make it appear as if you are distributing spam. This approach is also referred to as email spoofing.