Sender Policy Framework, or SPF, is a validation system, which is designed to prevent the so-called e-mail spoofing where an e-mail message is sent from one email address, but to seem as being sent from another one, ordinarily with the purpose to scam the recipient for some reason. If SPF protection is enabled for a domain, a special record is created for it in the Domain Name System and all of the DNS servers around the world have it. The record includes all the e-mail servers that are permitted to send valid messages from an address within the domain. When a message is sent, the first DNS server it encounters checks the SPF record and if the sending server is authorized, the message is forwarded to the target destination. In case, however, the sending server is not present in the SPF record for the specified domain, the email message will not be sent and it will be discarded. Whenever you employ this solution, it'll stop third parties from sending spam e-mails that seem to have been sent from you.