MTA-STS Policy Examples and Testing

MTA-STS requires HTTPS-hosted policy and bootstrap TXT. Test fetch and trust.

Steps

1. Publish policy and _mta-sts TXT
2. Validate HTTPS and certificate
3. Analyze TLSRPT feedback

FAQ

Testing policy changes?

Increment id on TXT and re-fetch policy.

Validation & Screenshots

MTA-STS Fetch Validation

1. Verify https://mta-sts.yourdomain.com/.well-known/mta-sts.txt is reachable with valid TLS
2. Check _mta-sts TXT contains a current id
3. Inspect TLSRPT for policy fetch or TLS negotiation failures

Screenshot placeholder (optional): /assets/guides/common/mta-sts-policy-fetch.png

Platform Validators

• TXT Lookup
• DMARC Report Analyzer
• Email Health Checker