The Sender Policy Framework (SPF) record is a validation mechanism used to prevent email spoofing. This policy allows the sender to list all the addresses from which emails will be sent on their behalf. During SPF validation, the email header is checked to see if it has been sent from one of those authorized addresses to rule out the possibility that the email could be spam.

Click here to learn more about SPF and here to learn how to setup SPF for your domain in Zoho Campaigns.