Email authentication failure (SPF/DKIM/DMARC)
Email authentication failure (SPF/DKIM/DMARC): what it means, why it may matter, and how to remediate with external verification using ExposureGrid.
The problem
Email authentication failure (SPF/DKIM/DMARC): DNS records define how the internet routes users and mail for your domain. Misconfigurations can create takeover, mail, or certificate issuance risks.
Why it matters
DNS issues may be informational or materially risky depending on record type and environment - validate before assuming exploitation.
How to check
Review authoritative DNS, trace CNAME chains, inspect CAA, MX, and delegation health. ExposureGrid summarizes externally visible posture.
How to fix
Remove stale records, fix dangling targets, publish intentional CAA, align apex/www consistency, validate MX ownership, document changes.
- Identify owners for the affected component (app, edge, DNS, or mail).
- Make a minimal change and validate in staging or a canary route.
- Deploy with monitoring and rollback readiness.
- Re-run ExposureGrid to confirm the external signal improved.
Run a scan to verify this fix on your domain
Use the same public scanner as the homepage — results honor your plan tier.
Scan your domainWhat ExposureGrid checks
ExposureGrid runs external DNS probes aligned with managed scan tiers.
FAQ
- Why does "Email authentication failure (SPF/DKIM/DMARC)" appear in ExposureGrid?
- Scanners observe externally visible signals. A finding means our rules matched - validate severity and applicability in your environment.
- Could this be a false positive?
- Yes, depending on context and coverage limits. Especially for heuristic, partial, or pattern-based checks, corroborate with manual review.
- What should I do after changing configuration?
- Re-run a scan to confirm the external signal changed, then enable monitoring where your plan supports it.
Related pages
ExposureGrid continuously monitors these issues and alerts you before they become exploitable.