Sender Policy Framework, or SPF, is a verification system, that is employed to stop the so-called email spoofing where an email message is sent from one address, but to look as being sent from a different one, ordinarily with the objective to scam the recipient someway. When SPF protection is enabled for a domain name, a special record is created for it in the Domain Name System and all DNS servers globally receive it. The record features all of the e-mail servers that are allowed to send authentic messages from an email address part of the domain. When an e-mail is sent, the first DNS server it goes to checks the SPF record and if its sending server is permitted, the message is sent to the target receiver. In case, however, the sending server is not present in the SPF record for the particular domain, the email message will not be sent and it will be removed. In case you employ this service, it will stop third parties from sending spam emails that seem to have been sent by you.