SPF, which is short for Sender Policy Framework, is an email safety system, that is is intended to validate if an email message is sent by an official server. Using 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 creates a special record in the Domain Name System (DNS) that contains the IP addresses of the servers that are permitted to send e-mail messages from mail boxes under the domain. As soon as this record propagates worldwide, it exists on all of the DNS servers that route the Internet traffic. Whenever an email message is sent, the initial DNS server it goes through verifies if it comes from an authorized server. When it does, it is forwarded to the destination address, yet if it doesn't come from a server listed in the SPF record for the domain, it is discarded. In this way nobody will mask an e-mail address then make it look as if you are sending spam messages. This method is also known as email spoofing.