Sender Policy Framework, or SPF, is a validation system, that is intended to stop the so-called email spoofing where an email message is sent from one address, but to appear as being sent from another one, often with the idea to scam the recipient someway. When SPF protection is enabled for a domain, a specific record is created for it in the Domain Name System and all the DNS servers around the world receive it. The record contains all the mail servers that are permitted to send authentic messages from an email address under the domain. When an email is sent, the very first DNS server it goes to verifies the SPF record and in case its sending server is permitted, the message is forwarded to the targeted destination. When, however, the sending server doesn't exist in the SPF record for the given domain, the e-mail message won't be forwarded and it will be removed. When you employ this solution, it will prevent third parties from sending spam messages which appear to have been sent by you.