Sender Policy Framework, or SPF, is a verification system, which is employed to prevent the so-called email spoofing where an email message can be sent from one address, but to seem as being sent from another, typically with the idea to fraud the recipient in some way. If SPF protection is enabled for a domain name, a special record is generated for it in the Domain Name System and all the DNS servers globally receive it. The record features all of the email servers that are allowed to send legitimate messages from an address under the domain. When an e-mail is sent, the very first DNS server it encounters checks the SPF record and if its sending server is permitted, the message is forwarded to the target receiver. In case, however, the sending server is not included in the SPF record for the particular domain, the message will not be sent and it will be removed. In the event that you use this solution, it'll stop third parties from sending spam emails which appear to have been sent by you.