Sender Policy Framework, or SPF, is a validation system, which is used to stop the so-called email spoofing where an e-mail message can be sent from one e-mail address, but to look as being sent from another, frequently with the idea to scam the recipient someway. When SPF protection is enabled for a domain, a specific record is made for it in the Domain Name System and all DNS servers worldwide get it. The record includes all of the e-mail servers that are permitted to send authentic messages from an email address within the domain. When an e-mail is sent, the very first DNS server it encounters verifies the SPF record and when its sending server is authorized, the message is sent to the targeted receiver. If, 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 will be discarded. If you use this service, it will stop third parties from sending spam messages which appear to have been sent by you.