ZeroHookZeroHook
Free MTA-STS Tool

Free MTA-STS Validator

Check your MTA-STS DNS record and policy file in one click — no account required.

  • Validate _mta-sts TXT record presence and format
  • Fetch and verify the policy file from your server
  • 3 lookups per day — no login needed
Why MTA-STS?

Ensure encrypted email delivery.

MTA-STS prevents downgrade attacks and enforces TLS encryption for email in transit.

Prevent Downgrade Attacks

MTA-STS forces TLS encryption, stopping attackers from intercepting emails.

Improve Security Posture

Major providers support MTA-STS, strengthening your domain's email security.

Complements DMARC

Works alongside DMARC and SPF for comprehensive email security.

Go beyond one-off scans

Fix issues before they affect customers

Get automated monitoring, real-time alerts, and continuous scanning.

Free Account

  • Copy-paste DNS fixes
  • Daily automated scans
  • Real-time alerts
  • Full security audit
Deliverability

Full monitoring

  • Copy-paste DNS fixes
  • Daily automated scans
  • Real-time alerts
  • Full security audit

Free forever plan available · Paid plans from $49/mo