SPF, which is an acronym for Sender Policy Framework, is an email security system, which is is intended to verify if an email message was sent by a licensed server. Using SPF protection for a particular domain name will stop the faking of email addresses created with the domain. In layman's terms: enabling this function for a domain generates a special record in the Domain Name System (DNS) containing the IP of the servers that are allowed to send e-mail messages from mail boxes using the domain. Once this record propagates globally, it will exist on all DNS servers that route the Internet traffic. Any time some e-mail message is sent, the first DNS server it goes through verifies if it originates from an official server. When it does, it is forwarded to the destination address, yet if it does not originate from a server indexed in the SPF record for the particular domain, it's discarded. Thus nobody can mask an email address then make it appear as if you're sending spam messages. This approach is also known as email spoofing.