SPF, which stands for Sender Policy Framework, is an email safety system, which is designed to validate if an email message is sent by a certified server. Using SPF protection for a given domain name will stop the counterfeiting of emails generated with the domain. In layman's terms: activating this function for a domain name makes a particular record in the Domain Name System (DNS) containing the IP of the servers that are permitted to send e-mails from mail boxes using the domain. Once this record propagates worldwide, it exists on all of the DNS servers that route the Internet traffic. Whenever an email message is sent, the initial DNS server it goes through tests if it originates from an official server. If it does, it's forwarded to the destination address, but when it does not originate from a server part of the SPF record for the domain, it is rejected. Thus nobody can mask an e-mail address and make it look as if you are sending spam messages. This method is also identified as email spoofing.