SPF, which stands for Sender Policy Framework, is an email protection system, that is used to confirm if an email message is sent by a licensed server. Using SPF protection for a particular domain will prevent the counterfeiting of emails made with the domain. In layman's terms: activating this attribute for a domain name makes a special record in the Domain Name System (DNS) that contains the IP addresses of the servers that are allowed to send e-mail messages from mail boxes under the domain. Once this record propagates globally, it exists on all DNS servers that direct the Internet traffic. Every time some e-mail message is sent, the first DNS server it goes through tests if it originates from an accredited server. If it does, it's forwarded to the destination address, however if it does not originate from a server part of the SPF record for the domain, it is rejected. In this way nobody will mask an email address and make it look as if you're sending spam messages. This technique is also identified as email spoofing.