Postfix MTA-STS & TLSRPT Setup

Publish MTA-STS policy and TLS reporting to improve secure mail delivery for Postfix.
1 min read
Updated 2025-10-23
Tutorials
postfixmta-ststlsrptsmtp

Overview: Enforce TLS for SMTP with MTA-STS and collect TLS reports (TLSRPT) for insight.

Prerequisites: HTTPS hosting for policy, DNS control, Postfix config access.

Steps

  1. Host policy at https://mta-sts.yourdomain/.well-known/mta-sts.txt with mode=enforce.
  2. Publish DNS: _mta-sts TXT and _smtp._tls TXT for TLSRPT.
  3. Verify TLS: ensure server presents valid certificate and supports modern ciphers.

Verification

Troubleshooting

  • Policy cache: mailbox providers cache; allow time after updates.
  • Certificate errors: renew or fix intermediate chain.

FAQ

Q: Does MTA-STS affect DMARC? A: No; it governs SMTP TLS, complementary to DMARC.

Related Tools

Email Health TCP Port Check

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