SPF, which stands for Sender Policy Framework, is an email safety system, that is is intended to validate whether an e-mail message is sent by an official server. Employing SPF protection for a particular domain name will stop the forging of email addresses made with the domain. In layman's terms: enabling this function for a domain name generates a particular record in the Domain Name System (DNS) which includes the IP addresses of the servers that are allowed to send e-mails from mailboxes under the domain. As soon as this record propagates globally, it exists on all of the DNS servers that route the Internet traffic. When some e-mail message is sent, the initial DNS server it uses tests if it originates from an official server. In the event it does, it is forwarded to the destination address, however if it does not come from a server indexed in the SPF record for the particular domain, it's rejected. In this way nobody will be able to mask an email address and make it appear as if you are distributing spam. This approach is also referred to as email spoofing.