SPF, which is an acronym for Sender Policy Framework, is an e-mail safety system, which is designed to verify whether an email message was sent by a certified server. Using SPF protection for a particular domain will prevent the counterfeiting of emails generated with the domain. In simple words: activating this function for a domain name makes a particular record in the Domain Name System (DNS) that contains the IP of the servers that are permitted to send emails from mail boxes using the domain. As soon as this record propagates globally, it will exist on all DNS servers that route the Internet traffic. When some email message is sent, the first DNS server it uses tests if it originates from an authorized server. In the event it does, it is forwarded to the destination address, however if it does not come from a server part of the SPF record for the particular domain, it is discarded. In this way nobody will be able to mask an email address and make it look as if you are e-mailing spam messages. This technique is also referred to as email spoofing.
