Sender Policy Framework, or SPF, is a validation system, that is designed to stop the so-called email spoofing where an email message can be sent from one e-mail address, but to seem as being sent from a different one, frequently with the idea to fraud the recipient for some reason. If SPF protection is enabled for a domain name, a special record is made for it in the Domain Name System and all DNS servers around the world receive it. The record features all the email servers that are allowed to send authentic messages from an e-mail address part of the domain. When an email is sent, the very first DNS server it encounters checks the SPF record and if its sending server is authorized, the message is sent to the target destination. In case, however, the sending server is not contained in the SPF record for the specified domain, the email message won't be submitted and it will be discarded. In the event that you employ this solution, it will stop third parties from sending spam which appear to have been sent from you.