SPF, which stands for Sender Policy Framework, is an e-mail safety system, which is designed to validate if an e-mail message was sent by an official server. Using SPF protection for a particular domain will stop the faking of emails made with the domain. In simple words: enabling this attribute for a domain makes a specific record in the Domain Name System (DNS) containing the IP of the servers that are allowed to send e-mails from mail boxes under the domain. Once this record propagates worldwide, it will exist on all of the DNS servers that route the Internet traffic. When a new e-mail message is sent, the first DNS server it goes through tests whether it comes from an official server. In the event it does, it is sent to the destination address, yet when it does not come from a server listed in the SPF record for the particular domain, it's rejected. In this way nobody will mask an e-mail address to make it look as if you are e-mailing spam messages. This approach is also called email spoofing.