Sender Policy Framework, also abbreviated as SPF. SPF is a framework designed to prevent email phishing/forgery. With SPF, if a spammer attempts to send emails with a faked “from” address, the message will be rejected by mail servers that uses SPF verification.
An SPF record is a single TXT entry in the DNS for each domain. This TXT record contains information such as the mail server’s outgoing IP address, which can be used to verify the authenticity of the email messages that claims to come from the domain name in question. If the email message comes from an IP that is different from what is specified in the SPF record, it will be rejected.