SPF, which stands for Sender Policy Framework, is an email safety system, that is used to confirm whether an email message is sent by a licensed server. Employing SPF protection for a domain name will prevent the counterfeiting of emails generated with the domain. In layman's terms: enabling this feature for a domain makes a special record in the Domain Name System (DNS) which includes the IP of the servers that are allowed to send emails from mailboxes under the domain. Once this record propagates worldwide, it exists on all the DNS servers that route the Internet traffic. Whenever a new e-mail message is sent, the first DNS server it goes through verifies if it originates from an authorized server. In the event it does, it is sent to the destination address, but when it doesn't come from a server part of the SPF record for the particular domain, it is discarded. Thus nobody will mask an email address and make it appear as if you're distributing spam messages. This approach is also termed email spoofing.