SPF, which is an acronym for Sender Policy Framework, is an e-mail protection system, that is is intended to verify if an email message was sent by a certified server. Using SPF protection for a given domain will prevent the faking of emails made with the domain. In layman's terms: activating this attribute for a domain name creates a special record in the Domain Name System (DNS) which includes the IP addresses of the servers that are allowed to send e-mail messages from mailboxes using the domain. Once this record propagates worldwide, it will exist on all the DNS servers that route the Internet traffic. Any time an e-mail message is sent, the initial DNS server it goes through verifies if it originates from an approved server. If it does, it is forwarded to the destination address, however if it doesn't originate from a server part of the SPF record for the domain, it is discarded. In this way nobody can mask an e-mail address then make it look as if you're distributing spam. This approach is also referred to as email spoofing.