Sender Policy Framework, or SPF, is a verification system, which is intended to prevent the so-called e-mail spoofing where an e-mail message can be sent from one email address, but to seem as being sent from another, ordinarily with the idea to fraud the recipient in some way. If SPF protection is enabled for a domain name, a unique record is created for it in the Domain Name System and all the DNS servers globally get it. The record features all email servers that are permitted to send valid messages from an email address under the domain. When an email is sent, the very first DNS server it encounters verifies the SPF record and if its sending server is authorized, the message is forwarded to the targeted receiver. In case, however, the sending server is not contained in the SPF record for the given domain, the message won't be forwarded and it will be discarded. If you use this service, it will stop third parties from sending spam messages that look as if they have been sent by you.
