Sender Policy Framework, or SPF, is a validation system, that is used to stop the so-called e-mail spoofing where an email message is sent from one e-mail, but to seem as being sent from a different, generally with the purpose to scam the recipient in some way. If SPF protection is activated for a domain name, a specific record is made for it in the Domain Name System and all of the DNS servers globally get it. The record features all of the mail servers that are allowed to send authentic messages from an email address part of the domain. When an email is sent, the first DNS server it encounters checks the SPF record and in case 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 message won't be forwarded and it will be removed. Whenever you employ this solution, it will prevent third parties from sending spam emails that look as if they have been sent by you.