The SPF (Sender Policy Framework) is an email-authentication technique which is used to prevent spammers from sending messages on behalf of your domain.
With SPF organizations can authorize mail servers.
Together with the DMARC information, SPF gives the receiving server and domain some critical information on how trustworthy your mail server is.
SPF is an email authentication technique that relies on DNS records. SPF specifies the identity of mail servers that are permitted to send email on behalf of your domain.
