Sender Policy Framework, or SPF, is a validation system, which is intended to prevent the so-called email spoofing where an email message can be sent from one email address, but to appear as being sent from another, generally with the idea to fraud the recipient for some reason. When SPF protection is activated for a domain name, a unique record is created for it in the Domain Name System and all DNS servers around the world have it. The record features all of the email servers that are allowed to send valid messages from an address within the domain. When an email is sent, the first DNS server it goes to verifies the SPF record and when its sending server is permitted, the message is sent to the target receiver. If, however, the sending server is not contained in the SPF record for the given domain, the email message will not be sent and it will be discarded. In the event that you employ this solution, it will stop third parties from sending spam which appear to have been sent from you.