Sender Policy Framework, or SPF, is a verification system, that is used to prevent the so-called e-mail spoofing where an e-mail message can be sent from one email, but to appear as being sent from another one, frequently with the idea to scam the recipient for some reason. If SPF protection is activated for a domain name, an exclusive record is created for it in the Domain Name System and all DNS servers worldwide get it. The record features all the email servers that are permitted to send legitimate messages from an email address within the domain. When a message is sent, the very first DNS server it encounters verifies the SPF record and if the sending server is authorized, the message is sent to the target destination. When, however, the sending server is not contained in the SPF record for the specified domain, the e-mail message won't be sent and it'll be discarded. In the event that you employ this solution, it will stop third parties from sending spam e-mails which appear to have been sent by you.