Sender Policy Framework, or SPF, is a verification system, which is intended to prevent the so-called e-mail spoofing where an e-mail message can be sent from one email address, but to appear as being sent from another one, ordinarily with the purpose to scam the recipient in some way. When SPF protection is enabled for a domain, a specific record is generated for it in the Domain Name System and all DNS servers worldwide get it. The record includes all the email servers that are permitted to send valid messages from an e-mail address under the domain. When a message is sent, the first DNS server it goes to checks the SPF record and when its sending server is authorized, the message is sent to the target destination. If, however, the sending server is not contained in the SPF record for the specified domain, the email message will not be forwarded and it'll be discarded. When you use this solution, it will stop third parties from sending spam messages which appear to have been sent from you.