SPF, which stands for Sender Policy Framework, is an email safety system, which is is intended to verify whether an email message was sent by an authorized server. Employing SPF protection for a particular domain name will stop the forging of emails created with the domain. In simple words: activating this feature for a domain generates a particular record in the Domain Name System (DNS) which contains the IP addresses of the servers that are permitted to send e-mails from mailboxes using the domain. As soon as this record propagates globally, it exists on all of the DNS servers that route the Internet traffic. Whenever a new email message is sent, the initial DNS server it goes through tests if it comes from an authorized server. If it does, it's forwarded to the destination address, however if it doesn't originate from a server indexed in the SPF record for the particular domain, it is rejected. Thus nobody will mask an e-mail address and make it appear as if you're e-mailing spam. This method is also referred to as email spoofing.