SPF, which stands for Sender Policy Framework, is an email safety system, which is is intended to confirm whether an e-mail message is sent by an official server. Employing SPF protection for a given domain will prevent the counterfeiting of emails generated with the domain. In simple words: activating this function for a domain name creates a particular record in the Domain Name System (DNS) that contains the IP addresses of the servers which are allowed to send email messages from mail boxes under the domain. Once this record propagates worldwide, it exists on all the DNS servers that direct the Internet traffic. Every time a new e-mail message is sent, the initial DNS server it uses tests if it comes from an authorized server. If it does, it's sent to the destination address, yet if it doesn't come from a server indexed in the SPF record for the particular domain, it's discarded. Thus nobody will mask an email address to make it look as if you're distributing spam. This approach is also called email spoofing.