SPF, which is an acronym for Sender Policy Framework, is an email safety system, which is used to confirm whether an email message is sent by an authorized server. Using SPF protection for a particular domain will prevent the faking of emails generated with the domain. In layman's terms: activating this function for a domain creates a specific record in the Domain Name System (DNS) that contains the IP of the servers that are permitted to send email messages from mailboxes under the domain. The moment this record propagates worldwide, it will exist on all of the DNS servers that direct the Internet traffic. Any time a new email message is sent, the initial DNS server it uses checks if it comes from an authorized server. In the event it does, it is forwarded to the destination address, yet if it does not originate from a server indexed in the SPF record for the domain, it's rejected. Thus nobody can mask an e-mail address to make it look as if you're sending spam. This approach is also referred to as email spoofing.