Free tool
SPF, DMARC & email DNS check
Audit SPF, DMARC, MX, MTA-STS, and BIMI TXT records.
This email DNS audit fetches SPF, DMARC, MX, and related policy records (MTA-STS, BIMI when present). Use it when onboarding a new ESP, hardening spoofing defenses, or debugging deliverability.
What we check
SPF lists authorized senders in a TXT record. DMARC sets a policy for failures and reporting. MX shows where mail should be delivered. Extra TXT policies like MTA-STS and BIMI appear when published. All lookups use free public DNS — no mailbox password required.
How to interpret failures
Missing SPF or DMARC is the most common gap. Multiple SPF strings on the same name are invalid. Overly long SPF include chains hit the 10-lookup limit. DMARC at p=none is fine for monitoring; move toward quarantine/reject only after reports look clean.
- One SPF TXT per name — merge mechanisms instead of adding records
- Align From: domain with DKIM/SPF for DMARC pass
- Re-check after DNS TTL when you publish changes
Not a full inbox test
This tool does not send mail or validate DKIM signatures on live messages. It audits the DNS posture receivers will query. Combine with PTR and blacklist checks on your sending IPs.
FAQ
Deeper guide: Read: SPF and DMARC explained