SPF, which is short for Sender Policy Framework, is an e-mail security system, which is designed to verify if an e-mail message was sent by a licensed server. Employing SPF protection for a domain name will stop the forging of emails made with the domain. In layman's terms: activating this function for a domain generates a particular record in the Domain Name System (DNS) that contains the IP of the servers which are allowed to send e-mail messages from mailboxes under the domain. Once this record propagates globally, it will exist on all of the DNS servers that route the Internet traffic. Any time some e-mail message is sent, the first DNS server it uses checks if it comes from an authorized server. If it does, it is forwarded to the destination address, yet when it does not come from a server indexed in the SPF record for the particular domain, it's rejected. Thus nobody will mask an email address and make it appear as if you're distributing spam. This approach is also identified as email spoofing.