SPF, which stands for Sender Policy Framework, is an email safety system, that is used to verify whether an e-mail message was sent by a certified server. Employing SPF protection for a particular domain will prevent the faking of email addresses made with the domain. In simple words: activating this function for a domain name creates a specific record in the Domain Name System (DNS) which includes the IP addresses of the servers that are permitted to send emails from mail boxes using the domain. The moment this record propagates globally, it exists on all DNS servers that direct the Internet traffic. Whenever a new e-mail message is sent, the initial DNS server it uses checks whether it originates from an accredited server. In the event it does, it's forwarded to the destination address, however 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 be able to mask an email address and make it look as if you are e-mailing spam messages. This technique is also termed email spoofing.