Email Authentication (SPF, DKIM, DMARC): Deployment Guide
Stop domain spoofing: roll out SPF, DKIM, and DMARC to p=reject without breaking legitimate mail.
Who this applies to
Every domain that sends email — and every domain that doesn't (attackers spoof non-sending domains too). Required or expected by Google/Yahoo bulk-sender rules, PCI DSS 4.0, and an increasing number of procurement checklists.
Practical technical guidance, not legal advice.
Key requirements
SPF
DNS record authorizing your sending servers. Keep lookups under 10.
DKIM
Cryptographic signatures on outgoing mail, verified via DNS public key.
DMARC
Policy telling receivers what to do with failures — and reports showing who's sending as you.
p=reject
The end state: unauthenticated mail claiming to be you is rejected outright.
How AIClicks helps
Email security checker
Checks SPF, DKIM (common selectors), DMARC, BIMI, and MTA-STS in one free scan.
Monitoring
Alerts when records change or expire.
Compliance steps
- Scan your domain free to see current SPF/DKIM/DMARC state.
- Publish SPF covering all legitimate senders (test with ~all first).
- Enable DKIM in your mail provider and publish the key.
- Publish DMARC at p=none with a rua mailbox; review reports for 2 weeks.
- Move to p=quarantine, then p=reject.
FAQ
Will DMARC break my newsletters?
Only if your newsletter provider isn't in SPF/DKIM. Include every legitimate sender before enforcing.
How long does rollout take?
Typically 2–4 weeks of monitoring at p=none before enforcing.
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