SPF, which is an acronym for Sender Policy Framework, is an email safety system, that is is intended to confirm whether an email message was sent by a certified server. Using SPF protection for a given domain name will prevent the faking of email addresses created with the domain. In simple words: activating this function for a domain creates a specific record in the Domain Name System (DNS) that contains the IP of the servers which are allowed to send emails from mailboxes under the domain. When this record propagates worldwide, it exists on all of the DNS servers that route the Internet traffic. When a new email message is sent, the initial DNS server it uses checks if it originates from an approved server. When it does, it is sent to the destination address, but if it doesn't originate from a server indexed in the SPF record for the domain, it's discarded. Thus nobody will be able to mask an e-mail address and make it appear as if you are sending spam messages. This method is also called email spoofing.