SPF, which means Sender Policy Framework, is an email protection system, that is employed to confirm whether an email message is sent by an authorized server. Using SPF protection for a given domain name will stop the counterfeiting of email addresses made with the domain. In layman's terms: enabling this function for a domain name makes a special record in the Domain Name System (DNS) which includes the IP addresses of the servers which are permitted to send e-mail messages from mail boxes using the domain. Once this record propagates globally, it will exist on all DNS servers that route the Internet traffic. Whenever some e-mail message is sent, the first DNS server it goes through checks whether it comes from an official server. In the event it does, it's sent to the destination address, but when it doesn't originate from a server indexed in the SPF record for the domain, it's discarded. In this way nobody will be able to mask an email address then make it appear as if you're distributing spam messages. This approach is also called email spoofing.