SPF, which stands for Sender Policy Framework, is an e-mail protection system, that is designed to confirm if an email message is sent by a certified server. Using SPF protection for a particular domain name will stop the counterfeiting of email addresses made with the domain. In simple words: enabling this attribute for a domain makes a special record in the Domain Name System (DNS) containing the IP addresses 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 DNS servers that route the Internet traffic. Any time an email message is sent, the initial DNS server it uses tests if it originates from an approved server. When it does, it is sent to the destination address, yet if it does not originate from a server part of the SPF record for the domain, it is rejected. Thus nobody will be able to mask an email address then make it look as if you're distributing spam. This approach is also called email spoofing.