TLS-RPT

TLS-RPT guides and tutorials: monitor SMTP TLS failures with SMTP TLS Reporting (RFC 8460).

4 articles

March 2026

Diagram showing the progression of MTA-STS deployment from testing mode to enforce mode

CaptainDNS · March 10, 2026

From testing to enforce: a progressive MTA-STS deployment strategy

Testing mode monitors, enforce mode blocks. This guide details the four steps to deploy MTA-STS progressively, from the initial policy to TLS-RPT reports, through to switching to enforce.

February 2026

Analyzing a TLS-RPT report: JSON structure and TLS email error types

CaptainDNS · February 14, 2026

Analyze and leverage your TLS-RPT reports: detect issues before they impact your emails

A practical guide to reading and leveraging TLS-RPT reports: JSON structure, failure types, diagnosing certificate and STARTTLS errors, and a daily analysis workflow.

Set up TLS-RPT on Microsoft 365, Google Workspace, and OVHcloud

CaptainDNS · February 13, 2026

Set up TLS-RPT: step-by-step guide for Microsoft 365, Google Workspace, and OVHcloud

Hands-on tutorial to set up TLS-RPT (SMTP TLS Reporting) on Microsoft 365, Google Workspace, and OVHcloud. DNS record, verification, and troubleshooting included.

TLS-RPT: monitoring TLS encryption failures in email delivery

CaptainDNS · February 10, 2026

TLS-RPT: The Complete Guide to Monitoring Email TLS Security

TLS-RPT (RFC 8460) lets you receive reports on TLS encryption failures in your email delivery. Learn how to configure it, read reports, and take action.