Sender Policy Framework, or SPF, is a validation system, which is employed to prevent the so-called e-mail spoofing where an email message can be sent from one e-mail, but to look as being sent from another one, often with the idea to fraud the recipient someway. If SPF protection is activated for a domain, an exclusive record is made for it in the Domain Name System and all DNS servers around the world get it. The record features all the mail servers that are permitted to send legitimate messages from an email address part of the domain. When an email is sent, the first DNS server it goes to verifies the SPF record and in case the sending server is permitted, the message is sent to the target receiver. If, however, the sending server is not contained in the SPF record for the specified domain, the email message will not be forwarded and it will be removed. When you employ this service, it will stop third parties from sending spam emails which seem to have been sent from you.