Sender Policy Framework, or SPF, is a verification system, which is used to stop the so-called e-mail spoofing where an email message can be sent from one email, but to appear as being sent from a different one, often with the purpose to scam the recipient in some way. If SPF protection is activated for a domain, a unique record is generated for it in the Domain Name System and all the DNS servers worldwide receive it. The record includes all of the e-mail servers that are permitted to send authentic messages from an address within the domain. When a message is sent, the first DNS server it goes to checks the SPF record and when the sending server is permitted, the message is forwarded to the targeted destination. If, however, the sending server is not included in the SPF record for the given domain, the email message will not be sent and it'll be removed. When you employ this solution, it'll prevent third parties from sending spam e-mails that seem to have been sent from you.