SPF, which is an acronym for Sender Policy Framework, is an e-mail safety system, which is used to confirm whether an email message is sent by a licensed server. Employing SPF protection for a given domain will prevent the faking of email addresses created with the domain. In simple words: enabling this feature for a domain name creates a special record in the Domain Name System (DNS) which includes the IP of the servers which are permitted to send e-mail messages from mailboxes under the domain. Once this record propagates worldwide, it will exist on all of the DNS servers that route the Internet traffic. Every time an e-mail message is sent, the first DNS server it uses checks whether it comes from an official server. When it does, it is sent to the destination address, yet if it does not come from a server indexed in the SPF record for the domain, it is rejected. In this way nobody can mask an email address then make it look as if you're sending spam. This technique is also called email spoofing.