Sender Policy Framework, or SPF, is a verification system, that is intended to prevent the so-called e-mail spoofing where an e-mail message can be sent from one email, but to seem as being sent from a different one, generally with the purpose to fraud the recipient for some reason. If SPF protection is activated for a domain name, a unique record is created for it in the Domain Name System and all the DNS servers worldwide have it. The record contains all the mail servers that are permitted to send valid messages from an e-mail address within the domain. When an e-mail is sent, the first DNS server it encounters checks the SPF record and when its sending server is authorized, the message is forwarded to the targeted receiver. If, however, the sending server is not contained in the SPF record for the particular domain, the email message will not be forwarded and it'll be removed. When you employ this service, it will prevent third parties from sending spam emails that look as if they have been sent by you.