SPF, which is an acronym for Sender Policy Framework, is an email protection system, that is used to confirm whether an email message was sent by a certified server. Using SPF protection for a domain will stop the faking of email addresses created with the domain. In layman's terms: activating this attribute for a domain name generates a particular record in the Domain Name System (DNS) which contains the IP addresses of the servers which are allowed to send email messages from mailboxes using the domain. As soon as this record propagates globally, it will exist on all DNS servers that route the Internet traffic. When a new e-mail message is sent, the first DNS server it goes through verifies if it originates from an authorized server. In the event it does, it is sent to the destination address, yet if it does not originate from a server listed in the SPF record for the domain, it's discarded. In this way nobody can mask an e-mail address then make it look as if you are distributing spam messages. This method is also known as email spoofing.
