MTA-STS Inspector

Validate MTA-STS DNS records and retrieve HTTPS policy files.

DNS lookups and policy retrieval run from the PacketWizard server with SSRF protections and timeout handling.

What is MTA-STS Inspector?

MTA-STS tells sending mail servers to use TLS for SMTP to your domain according to a published HTTPS policy, reducing opportunistic downgrade risk.

How it works

PacketWizard validates the MTA-STS DNS TXT record and retrieves the HTTPS policy file for mode, MX patterns, and max age.

Common issues

  • DNS and HTTPS policy mismatch

    The id in DNS must change when the policy file changes. Stale IDs delay policy adoption at senders.

Frequently asked questions

What is testing vs enforce mode?

testing reports failures without requiring TLS; enforce instructs compliant senders to fail delivery when TLS policy cannot be met.

Continue with these related PacketWizard tools for adjacent diagnostics.