Sender Policy Framework, or SPF, is a verification system, which is designed to stop the so-called e-mail spoofing where an e-mail message is sent from one email address, but to appear as being sent from a different one, generally with the idea to fraud the recipient someway. When SPF protection is activated for a domain name, a unique record is generated for it in the Domain Name System and all DNS servers globally get it. The record includes all the e-mail servers that are allowed to send authentic messages from an email address within the domain. When an e-mail is sent, the first DNS server it encounters verifies the SPF record and in case its sending server is permitted, the message is forwarded to the target destination. When, however, the sending server is not included in the SPF record for the given domain, the email message won't be sent and it will be discarded. Whenever you employ this solution, it'll prevent third parties from sending spam messages which seem to have been sent from you.
