SPF, which is an acronym for Sender Policy Framework, is an e-mail safety system, which is designed to verify if an email message is sent by a licensed server. Employing SPF protection for a particular domain will stop the faking of emails generated with the domain. In layman's terms: enabling this attribute for a domain generates a specific record in the Domain Name System (DNS) which contains the IP of the servers that are allowed to send e-mails from mailboxes using the domain. When this record propagates globally, it will exist on all the DNS servers that route the Internet traffic. Every time an email message is sent, the initial DNS server it goes through verifies whether it comes from an accredited server. In the event it does, it's sent to the destination address, however when it doesn't originate from a server part of the SPF record for the domain, it's discarded. In this way nobody will be able to mask an email address and make it appear as if you're distributing spam. This approach is also called email spoofing.