SPF, which is an acronym for Sender Policy Framework, is an email protection system, that is employed to confirm if an e-mail message was sent by an official server. Employing SPF protection for a given domain name will prevent the forging of email addresses made with the domain. In simple words: activating this function for a domain name generates a particular record in the Domain Name System (DNS) which contains the IP of the servers that are permitted to send emails from mail boxes using the domain. When this record propagates globally, it exists on all of the DNS servers that direct the Internet traffic. Whenever an email message is sent, the initial DNS server it uses tests whether it originates from an accredited server. If it does, it is sent to the destination address, yet if it doesn't come from a server listed in the SPF record for the particular domain, it's rejected. Thus nobody can mask an email address to make it look as if you're distributing spam messages. This technique is also known as email spoofing.