Email Security

MTA-STS Checker

Validate MTA-STS records and policy publication to harden inbound SMTP transport.

About MTA-STS Checks

MTA-STS helps receiving mail systems require TLS for inbound delivery. This page checks the DNS record and policy availability that other senders rely on.

Why teams run this check

• Confirm the TXT policy record exists
• Verify policy mode and fetch path
• Review transport hardening posture
• Catch publication gaps before delivery issues appear

What to review

• Policy mode and max_age values
• Policy fetch status and host references
• Any DNS or HTTPS retrieval errors
• Whether inbound mail transport is enforceable

Use the free public result to review signals quickly, then move into the full workspace for continuous monitoring and deeper evidence.

PRO

Nodes Observed12

Resolved Nodes11

Dual-stack Coverage4 / 12

Refresh Window5m

PREVIEW

warningDKIM key strengthreview

errorMTA-STS missingfix

check_circleTLS-RPT not configuredinfo

PRO

PREVIEW

Real-time alertsDISABLED

Cadence—

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