Validate Strict Transport Security
Enter your domain to instantly verify your MTA-STS configuration. Ensure you are enforcing TLS encryption and blocking downgrade attacks in transit.
Real-Time DNS Validation & HTTPS Policy Diagnostics
Ensure your emails are cryptographically secured in transit against Man-in-the-Middle downgrade attacks. We execute direct, encrypted DNS over HTTPS (DoH) queries to validate your _mta-sts TXT records while simultaneously parsing your live HTTPS policy file at .well-known/mta-sts.txt. Guaranteeing absolute technical accuracy with strictly real-time operations and zero simulated data, our backend rigorously enforces TLS transit encryption and actively cross-references listed policy hosts against your live MX records to guarantee a flawless, highly-deliverable configuration.
Enter your domain to instantly verify your MTA-STS configuration. Ensure you are enforcing TLS encryption and blocking downgrade attacks in transit.
Mail Transfer Agent Strict Transport Security (MTA-STS) guarantees that emails are encrypted in transit. Use our tool to validate your dual DNS and HTTPS configuration.
_mta-sts TXT record (v=STSv1) and required id= tracker are perfectly formatted..well-known/mta-sts.txt is reachable and valid.testing to enforce is critical for actively blocking unencrypted mail transit.Your feedback has been submitted successfully. We appreciate your help in improving our tools.