SPF, which is short for Sender Policy Framework, is an email security system, that is designed to verify if an e-mail message is sent by an authorized server. Employing SPF protection for a domain name will stop the counterfeiting of email addresses created with the domain. In simple words: activating this attribute for a domain name creates a particular record in the Domain Name System (DNS) that contains the IP addresses of the servers which are permitted to send emails from mailboxes using the domain. When this record propagates worldwide, it will exist on all of the DNS servers that route the Internet traffic. Whenever a new email message is sent, the first DNS server it uses checks if it originates from an official server. If it does, it is forwarded to the destination address, but if it does not originate from a server listed in the SPF record for the domain, it's rejected. In this way nobody will be able to mask an email address then make it appear as if you are distributing spam. This method is also called email spoofing.