SPF, which is an acronym for Sender Policy Framework, is an e-mail safety system, that is is intended to verify if an e-mail message is sent by an authorized server. Using SPF protection for a domain name will stop the counterfeiting of emails created with the domain. In layman's terms: enabling this function for a domain name creates a particular 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 using the domain. When this record propagates worldwide, it exists on all DNS servers that route the Internet traffic. Whenever a new e-mail message is sent, the first DNS server it goes through verifies whether it comes from an authorized server. If it does, it's sent to the destination address, but when it doesn't come from a server listed in the SPF record for the particular domain, it's discarded. Thus nobody can mask an e-mail address to make it look as if you are sending spam. This technique is also called email spoofing.