SPF, which stands for Sender Policy Framework, is an email security system, that is designed to confirm whether an e-mail message was sent by an authorized server. Using SPF protection for a domain name will stop the counterfeiting of email addresses made with the domain. In simple words: enabling this feature for a domain generates a particular record in the Domain Name System (DNS) which contains the IP of the servers which are permitted to send email messages from mailboxes under the domain. The moment this record propagates worldwide, it will exist on all the DNS servers that direct the Internet traffic. Every time some e-mail message is sent, the initial DNS server it goes through checks whether it originates from an approved server. When it does, it's sent to the destination address, however when it does not come from a server listed in the SPF record for the particular domain, it's rejected. Thus nobody will be able to mask an e-mail address then make it appear as if you are sending spam. This approach is also identified as email spoofing.