Sender Policy Framework, or SPF, is a verification system, which is used to prevent the so-called e-mail spoofing where an email message can be sent from one email address, but to seem as being sent from another, usually with the purpose to scam the recipient in some way. If SPF protection is activated for a domain name, an exclusive record is created for it in the Domain Name System and all of the DNS servers globally receive it. The record contains all of the e-mail servers that are permitted to send authentic messages from an address part of the domain. When a message is sent, the very first DNS server it goes to verifies the SPF record and in case the 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 given domain, the email message will not be forwarded and it will be removed. In the event that you employ this service, it will stop third parties from sending spam emails which look as if they have been sent by you.