Sender Policy Framework, or SPF, is a validation system, which is designed to stop the so-called e-mail spoofing where an e-mail message can be sent from one e-mail address, but to seem as being sent from another one, generally with the purpose to fraud the recipient in some way. When SPF protection is enabled for a domain name, an exclusive record is generated for it in the Domain Name System and all DNS servers globally get it. The record contains all e-mail servers that are allowed to send valid messages from an email address within the domain. When a message is sent, the first DNS server it encounters checks the SPF record and if its sending server is permitted, the message is sent to the target destination. If, however, the sending server is not contained in the SPF record for the given domain, the email message will not be submitted and it will be discarded. Whenever you employ this solution, it will stop third parties from sending spam e-mails which appear to have been sent by you.