SPF, which stands for Sender Policy Framework, is an e-mail protection system, that is used to verify whether an e-mail message was sent by a licensed server. Employing SPF protection for a particular domain will prevent the counterfeiting of email addresses generated with the domain. In layman's terms: activating this function for a domain generates a special record in the Domain Name System (DNS) which includes the IP of the servers that are permitted to send e-mails from mailboxes using the domain. When this record propagates globally, it exists on all the DNS servers that route the Internet traffic. Any time an e-mail message is sent, the initial DNS server it uses verifies whether it comes from an approved server. When it does, it is sent to the destination address, however if it does not come from a server listed in the SPF record for the particular domain, it is discarded. In this way nobody can mask an e-mail address then make it look as if you are sending spam messages. This technique is also identified as email spoofing.