SPF, which is an acronym for Sender Policy Framework, is an e-mail protection system, which is designed to confirm if an e-mail message is sent by an official server. Using SPF protection for a given domain will stop the faking of email addresses created with the domain. In layman's terms: enabling this function for a domain name creates a special record in the Domain Name System (DNS) which includes the IP of the servers which are permitted to send email messages from mail boxes using the domain. The moment this record propagates worldwide, it exists on all of the DNS servers that direct the Internet traffic. When an email message is sent, the first DNS server it goes through checks whether it comes from an authorized server. When it does, it is sent to the destination address, but if it doesn't come from a server indexed in the SPF record for the domain, it is rejected. In this way nobody can mask an email address and make it look as if you are e-mailing spam. This technique is also identified as email spoofing.