Sender Policy Framework, or SPF, is a verification system, which is intended to prevent the so-called email spoofing where an email message can be sent from one address, but to appear as being sent from a different, typically with the idea to scam the recipient someway. If SPF protection is enabled for a domain name, an exclusive record is made for it in the Domain Name System and all DNS servers around the world receive it. The record contains all email servers that are permitted to send legitimate messages from an e-mail address within the domain. When a message is sent, the very first DNS server it encounters checks the SPF record and when its sending server is permitted, the message is sent to the target destination. If, however, the sending server is not included in the SPF record for the specified domain, the email message won't be submitted and it'll be discarded. When you employ this solution, it'll prevent third parties from sending spam messages that seem to have been sent by you.