Cybersecurity Glossary
Email Authentication
The records that let receiving mail servers verify that a message really came from your domain.
What Email Authentication means
Three records work together. SPF lists who may send on your behalf, DKIM signs your messages cryptographically, and DMARC tells receivers what to do when a message fails and where to send reports. Together they make spoofing your domain far harder.
Why Email Authentication matters for small businesses and nonprofits
Without a DMARC policy set to reject, anyone can send mail that appears to come from your organisation. Major mail providers now also require these records for reliable delivery, so this affects whether your legitimate mail arrives at all.
What to do about Email Authentication
- Publish all three records and work up to a policy that rejects failures
- Read the DMARC reports for a few weeks before enforcing, to avoid blocking your own systems
- Include every service that sends on your behalf, such as newsletters and invoicing
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