SPF, which means Sender Policy Framework, is an email safety system, that is designed to verify if an email message was sent by an authorized server. Using SPF protection for a given domain name will stop the counterfeiting of emails generated with the domain. In layman's terms: activating this attribute for a domain name creates a specific record in the Domain Name System (DNS) that contains the IP of the servers that are permitted to send e-mail messages from mailboxes using the domain. The moment this record propagates worldwide, it exists on all of the DNS servers that route the Internet traffic. Any time some e-mail message is sent, the first DNS server it goes through tests whether it originates from an approved server. If it does, it is sent to the destination address, but if it does not come from a server listed in the SPF record for the domain, it is rejected. Thus nobody will be able to mask an e-mail address then make it look as if you're e-mailing spam messages. This technique is also known as email spoofing.