https://nalar.dev/tags/tls-rpt/ Recent content in TLS-RPT on Nalar Hugo en-us Wed, 23 Sep 2026 00:00:00 +0000 https://nalar.dev/tls-rpt-exposes-smtp-tls-failures-as-aggregate-reports/ Wed, 23 Sep 2026 00:00:00 +0000 https://nalar.dev/tls-rpt-exposes-smtp-tls-failures-as-aggregate-reports/ <p>SMTP transport security has an observability problem. A recipient domain can publish an MTA-STS policy or DANE TLSA records, yet many failures occur on remote sending systems: certificate validation can fail, an MX host can become unreachable, STARTTLS negotiation can break, or a published transport policy can be invalid. The recipient needs telemetry from those senders to distinguish a working deployment from a policy that silently blocks delivery.</p> <p>SMTP TLS Reporting, commonly called TLS-RPT, defines that telemetry channel in RFC 8460. A recipient domain publishes a DNS TXT record that names one or more report destinations. Participating sending systems then produce aggregate reports describing successful policy-compliant TLS sessions and failures encountered while delivering mail to that domain.</p>