SPF, which is short for Sender Policy Framework, is an email safety system, which is employed to confirm if an email message was sent by a certified server. Employing SPF protection for a domain name will stop the forging of email addresses generated with the domain. In simple words: enabling this attribute for a domain creates a specific record in the Domain Name System (DNS) which contains the IP of the servers that are allowed to send e-mail messages from mail boxes using the domain. The moment this record propagates worldwide, it will exist on all of the DNS servers that direct the Internet traffic. Every time some email message is sent, the initial DNS server it goes through tests if it comes from an accredited server. In the event it does, it's sent to the destination address, however if it doesn't come from a server listed in the SPF record for the particular domain, it is rejected. Thus nobody will mask an email address to make it look as if you are sending spam. This approach is also referred to as email spoofing.