SPF, which stands for Sender Policy Framework, is an e-mail safety system, which is designed to confirm whether an email message is sent by an official server. Employing SPF protection for a domain name will stop the forging of email addresses created with the domain. In simple words: 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 permitted to send emails from mail boxes using the domain. The moment this record propagates worldwide, it will exist on all DNS servers that direct the Internet traffic. Any time some e-mail message is sent, the initial DNS server it goes through tests if it originates from an official server. In the event it does, it is forwarded to the destination address, but if it doesn't come from a server listed in the SPF record for the particular domain, it's rejected. Thus nobody can mask an email address to make it look as if you are distributing spam messages. This approach is also called email spoofing.