MTA-STS Checker
Verify MTA-STS DNS records and policy hints.
About MTA-STS Checker
Confirm that a domain publishes an MTA-STS TXT record and see the policy tags at a glance. Use it to validate mail security posture before sending critical email. The lookup uses public DNS resolvers.
How to use
- Enter a domain name.
- Run the lookup to fetch the MTA-STS record.
- Review tags and open the policy file link.
Privacy
The tool performs DNS lookups only and does not store results.
FAQ
Where is the MTA-STS record stored?
It is published as a TXT record at _mta-sts.yourdomain.com.
What does v=STSv1 mean?
It indicates the version of the MTA-STS policy.
Do I need a policy file?
Yes. The policy file lives at https://mta-sts.yourdomain.com/.well-known/mta-sts.txt.
Does this tool validate HTTPS policy content?
It checks DNS and provides the policy link, but does not validate the file contents.
Which resolver is used?
You can choose Google or Cloudflare DNS.
Is any data stored?
No. Lookups are not stored.
For a fuller email security audit, pair this with DKIM Record Checker and BIMI Lookup.
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