SPF, which stands for Sender Policy Framework, is an e-mail protection system, which is designed to verify whether an e-mail message is sent by a licensed server. Employing SPF protection for a particular domain name will prevent the faking of email addresses generated with the domain. In layman's terms: enabling this attribute for a domain name generates a particular record in the Domain Name System (DNS) which contains the IP of the servers that are allowed to send emails from mail boxes under the domain. As soon as 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 first DNS server it goes through tests if it originates from an approved server. When it does, it is forwarded to the destination address, but when it does not come from a server part of the SPF record for the domain, it is rejected. In this way nobody will be able to mask an email address to make it appear as if you're e-mailing spam messages. This technique is also called email spoofing.