Domain Email Security Checker

MAG212 CYBER · Tools

Domain email security checker.

Can criminals send email pretending to be your company? Enter a domain to grade its SPF, DKIM, DMARC, MX, MTA-STS and BIMI records — with the exact DNS records to fix any gaps.

Check a domainWhat the records doSafe DMARC rollout

Check a domain

Try:

🔒 Only the domain name is looked up, using public DNS-over-HTTPS resolvers (Google Public DNS, with Cloudflare as a fallback). These are public records anyone can query. Nothing is stored by MAG212 CYBER.

What the records do

RecordWhereWhat it does
SPFTXT on domainLists the servers allowed to send mail for the domain. Must be one record, under 10 DNS lookups, ending in ~all or -all.
DKIMTXT on selector._domainkeyPublic key that verifies the cryptographic signature your mail server adds to every message.
DMARCTXT on _dmarcTells receivers what to do when a message fails SPF and DKIM alignment (none, quarantine or reject) and where to send reports.
MTA-STSTXT on _mta-sts + policy fileForces other mail servers to use verified TLS when delivering to you, blocking downgrade attacks.
TLS-RPTTXT on _smtp._tlsSends you reports when TLS delivery to your domain fails.
BIMITXT on default._bimiShows your logo in supporting inboxes. Requires DMARC at quarantine or reject.

Since 2024, Google and Yahoo require bulk senders to have SPF, DKIM and at least a p=none DMARC record. Got a suspicious message? Use the email header analyzer.

Safe DMARC rollout

  1. Monitor: publish p=none with a rua= reporting address and read the reports for 2–4 weeks.
  2. Fix: add every legitimate sender (CRM, newsletters, invoicing, help desk) to SPF and enable DKIM signing for each.
  3. Quarantine: move to p=quarantine, optionally with pct=25 and then 100.
  4. Reject: when reports are clean, move to p=reject. Spoofed mail is now blocked.
  5. Parked domains: domains that never send email should publish v=spf1 -all and v=DMARC1; p=reject.

Want us to run your DMARC rollout? Contact MAG212 CYBER.

⚖️ For education and use on systems you own or are authorised to test. Results are automated guidance, not a professional audit. See our terms of use and privacy policy.

Need expert help?

MAG212 CYBER offers network and cybersecurity consultation, plus security seminars for organisations around the world.

Explore our services →