What this tool checks
- _mta-sts TXT record
- HTTPS policy file
- version: STSv1 check
Email Deliverability Tools
MTA-STS Checker
Check MTA-STS DNS and policy file availability.
Run the check
Enter a public target. Checks are a point-in-time sample; private and internal addresses are blocked.
Why it matters
MTA-STS helps receiving servers enforce encrypted SMTP delivery.
Plain-English examples
- Check https://mta-sts.example.com/.well-known/mta-sts.txt
Recommended fixes
- Serve the policy over valid HTTPS
- Keep MX patterns accurate
Understanding the result
Use findings as a starting point, confirm the intended configuration with your provider, and retest after a change. A successful check does not guarantee security, delivery, uptime or search rankings. Results depend on public DNS and what the server exposes at the time of the check.
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Run these checks next for a fuller picture.
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