Home / MTA-STS Checker

MTA-STS Checker

Check your domain’s MTA-STS record and policy for secure email delivery.

Check MTA-STS Configuration

Configure your domain's MTA-STS record and policy before sending high volumes.

From MTA-STS Gaps to Secure Mail Delivery

Use this scan to confirm transport security readiness, publish missing MTA-STS values, and reduce downgrade or interception risk before major campaign sends.

Stop Sending Without Encrypted Transport Guarantees

SMTP downgrade and misrouting risks can quietly undermine sender trust. MTA-STS adds policy-level transport security controls so receivers know which MX hosts to trust and how to enforce TLS delivery.

This checker gives you one practical workflow to verify DNS signal, policy hosting, file syntax, certificate health, and MX TLS readiness.

Why MTA-STS Validation Is Non-Negotiable

Publishing MTA-STS incorrectly is almost as risky as not publishing it. You need DNS, hosting, policy formatting, and MX capability to align for secure and reliable email transport.

  • Reduce downgrade risk: Enforce TLS requirements for incoming mail transfers.
  • Protect brand trust: Ensure receiving systems validate the right MX infrastructure.
  • Prevent rollout mistakes: Catch policy syntax and hosting errors early.
  • Improve security posture: Pair MTA-STS checks with broader authentication controls.

DNS Signal Validation

Confirm _mta-sts TXT record structure so receivers can detect policy updates reliably.

Policy Hosting Checks

Verify mta-sts.txt is accessible at the mandatory HTTPS location with valid delivery response.

Syntax and Policy Logic

Validate required fields, mode, MX entries, and max_age values for enforceable policy behavior.

MX TLS Readiness

Best-effort probe of STARTTLS and TLS 1.2+ support across resolved MX hosts.

Fast Track to MTA-STS Readiness

  1. Scan: Enter your root domain and run the MTA-STS check.
  2. Review: Use the five result cards to identify exact setup gaps.
  3. Generate: Build the DNS TXT record and mta-sts.txt policy file in one step.
  4. Publish: Deploy records and file, then re-run to confirm secure transport posture.

Built for operators who need clear MTA-STS implementation guidance without toolchain complexity.

Need Help Fixing MTA-STS Fast?

Our experts can implement MTA-STS, align it with your MX architecture, and harden your email transport security without slowing down campaign operations.

MTA-STS Checker FAQs

What does this MTA-STS checker validate?

It checks DNS record presence, policy URL accessibility, policy syntax, certificate validity, and MX TLS support.

Can I generate MTA-STS values if my setup is missing?

Yes. The tool can generate both the _mta-sts TXT record and the full mta-sts.txt policy file.

Does a passed check mean my entire email security stack is complete?

No. MTA-STS is one layer. You should also maintain SPF, DKIM, DMARC, reputation, and list hygiene.

How often should I run an MTA-STS scan?

Re-check after policy updates, MX changes, certificate renewals, and before high-volume campaign sends.

More FAQs