SPF, which is short for Sender Policy Framework, is an e-mail security system, which is used to verify whether an e-mail message is sent by a certified server. Employing SPF protection for a domain name will prevent the forging of email addresses generated with the domain. In layman's terms: activating this feature for a domain generates a specific record in the Domain Name System (DNS) that contains the IP of the servers which are allowed to send emails from mailboxes using the domain. As soon as this record propagates globally, it will exist on all of the DNS servers that direct the Internet traffic. Whenever an e-mail message is sent, the first DNS server it goes through checks if it originates from an official server. When it does, it is forwarded to the destination address, yet if it doesn't come from a server part of the SPF record for the particular domain, it's discarded. Thus nobody can mask an email address to make it appear as if you are distributing spam. This approach is also identified as email spoofing.