Sender Policy Framework, or SPF, is a verification system, that is designed to stop the so-called email spoofing where an e-mail message can be sent from one address, but to seem as being sent from a different, often with the purpose to scam the recipient someway. When SPF protection is activated for a domain, a unique record is created for it in the Domain Name System and all of the DNS servers globally get it. The record includes all the mail servers that are permitted to send authentic messages from an address under the domain. When a message is sent, the very first DNS server it encounters verifies the SPF record and when its sending server is permitted, the message is forwarded to the targeted destination. If, however, the sending server is not present in the SPF record for the given domain, the e-mail message will not be forwarded and it will be removed. If you employ this solution, it will stop third parties from sending spam messages that seem to have been sent by you.