SPF, which stands for Sender Policy Framework, is an email protection system, which is is intended to validate whether an email message is sent by an authorized server. Using SPF protection for a given domain name will stop the faking of email addresses generated with the domain. In simple words: activating this function for a domain name creates a specific record in the Domain Name System (DNS) that contains the IP addresses of the servers that are permitted to send e-mails from mail boxes under the domain. When this record propagates globally, it will exist on all DNS servers that route the Internet traffic. When an email message is sent, the first DNS server it uses checks whether it originates from an official server. If it does, it is forwarded to the destination address, yet when it doesn't originate from a server indexed in the SPF record for the domain, it's rejected. In this way nobody will mask an email address to make it appear as if you're e-mailing spam messages. This approach is also referred to as email spoofing.