Sender Policy Framework, or SPF, is a verification system, which is intended to stop the so-called email spoofing where an email message is sent from one email address, but to appear as being sent from a different, often with the objective to scam the recipient for some reason. If SPF protection is enabled for a domain name, a special record is made for it in the Domain Name System and all of the DNS servers around the world get it. The record features all email servers that are permitted to send legitimate messages from an email address within the domain. When an email is sent, the first DNS server it goes to verifies the SPF record and in case its sending server is authorized, the message is sent to the targeted receiver. If, however, the sending server is not present in the SPF record for the given domain, the message won't be submitted and it will be removed. Whenever you use this solution, it will stop third parties from sending spam e-mails that seem to have been sent by you.