SPF, which is short for Sender Policy Framework, is an e-mail safety system, which is designed to confirm whether an email message was sent by a licensed server. Employing SPF protection for a domain name will stop the forging of email addresses generated with the domain. In layman's terms: activating this attribute for a domain generates a specific record in the Domain Name System (DNS) which contains the IP of the servers which are permitted to send emails from mail boxes under the domain. The moment this record propagates globally, it will exist on all DNS servers that route the Internet traffic. Any time an e-mail message is sent, the first DNS server it uses checks if it comes from an approved server. When it does, it's forwarded to the destination address, yet if it does not come from a server part of the SPF record for the domain, it is discarded. Thus nobody will be able to mask an e-mail address and make it look as if you're distributing spam messages. This method is also termed email spoofing.