Summary
MTA-STS (Mail Transfer Agent Strict Transport Security) is an internet standard that helps secure email communication through authentication and encryption, protecting against man-in-the-middle attacks. Receiving MTA-STS or TLS reports from Google indicates potential issues with TLS encryption when delivering emails to your domain. These reports provide insights into TLS connection failures, certificate problems, and other configuration errors, enabling domain owners to identify and fix these issues. While MTA-STS and TLS reporting are distinct, they are related, with TLS reporting providing feedback on the effectiveness of TLS connections. Broken IPv6 for Gmail reporting can cause issues, and using services like SocketLabs might generate more frequent reports. These reports might also simply be feedback on the setup of your MTA-STS configuration itself, and so requires monitoring and analysis for any potential security issues.
Key findings
- MTA-STS Purpose: MTA-STS enhances email security by enforcing TLS encryption and authentication to prevent man-in-the-middle attacks.
- Google's Reports: Google sends MTA-STS/TLS reports to alert domain owners about potential problems with TLS encryption during email delivery to their domain.
- Report Contents: Reports provide information about TLS connection failures, certificate issues, and other configuration errors that affect secure email delivery.
- TLS Reporting Role: TLS reporting is a related mechanism that provides feedback on the effectiveness of TLS connections and helps identify TLS-related configuration problems.
- IPv6 Issue: Broken IPv6 implementation for Gmail reporting can affect the delivery of MTA-STS/TLS reports.
Key considerations
- TLS Configuration: Review your TLS configuration upon receiving MTA-STS/TLS reports to identify and fix any issues affecting secure email delivery.
- MTA-STS Implementation: Consider implementing MTA-STS to proactively protect email communications against man-in-the-middle attacks.
- Report Analysis: Carefully analyze the contents of MTA-STS/TLS reports to understand the specific issues affecting TLS connections and take appropriate corrective actions.
- Distinct Mechanisms: Understand that MTA-STS and TLS reporting are distinct but related mechanisms, serving different purposes in securing email communications.
- MTA-STS Setup: The reports might simply be feedback on the setup of your MTA-STS configuration, this needs monitoring and analysis for any security problems.
What email marketers say
7 marketer opinions
MTA-STS reports, sometimes confused with TLS reports, are mechanisms related to email security. MTA-STS aims to prevent man-in-the-middle attacks by enforcing TLS encryption and authentication for email transmissions. The reports themselves provide feedback on TLS connection failures and other issues encountered when delivering emails to your domain. Receiving these reports from Google suggests that Google is encountering TLS-related problems when trying to send emails to you or that you are receiving feedback on your MTA-STS setup. Reports can be triggered daily and can also be triggered if you sign up for a list which uses SocketLabs, but broken IPv6 implementation can prevent them from showing in Gmail.
Key opinions
- MTA-STS Purpose: MTA-STS secures email communication by mandating TLS encryption and authentication, preventing man-in-the-middle attacks.
- Report Triggers: Reports can be triggered daily depending on email volume and configuration, or by problems being encountered with your servers.
- Report Content: Reports contain insights into TLS connection failures and other delivery issues, such as STARTTLS failures, TLS version issues, certificate problems, and unsupported encryption algorithms.
- Gmail IPv6 Issue: IPv6 implementation with Gmail might be broken causing failures in report delivery.
Key considerations
- TLS Configuration: If receiving MTA-STS reports from Google, carefully examine your TLS configuration and address any identified issues to ensure secure email delivery.
- MTA-STS Setup: The reports might simply be feedback on the setup of your MTA-STS configuration, this needs monitoring and analysis for any security problems.
- TLS vs. MTA-STS: Be aware that TLS reporting (TLSRPT) and MTA-STS are related but distinct mechanisms, serving different purposes in email security.
- Report Generation: Services like SocketLabs can be used to generate MTA-STS reports more frequently.
Marketer view
Marketer from Email Geeks suggests that signing up for a list that uses SocketLabs will generate reports more frequently, mentioning they get reports from them daily.
25 Jun 2021 - Email Geeks
Marketer view
Marketer from Email Geeks mentions that currently, IPv6 for Gmail reporting is broken.
2 Nov 2023 - Email Geeks
What the experts say
2 expert opinions
MTA-STS and/or TLS reports received from Google signal potential TLS connection issues impacting email delivery to your domain. Google sends these reports to help you identify and rectify configuration errors affecting secure communication with Gmail. Investigating your server's TLS setup is essential to resolve these problems.
Key opinions
- TLS Reporting Importance: TLS reporting provides crucial visibility into email delivery problems stemming from TLS encryption issues.
- Google's Intent: Google sends reports to alert domain owners about configuration errors that may be hindering secure email communication with Gmail.
- Actionable Insight: Reports offer insights that enable senders and receivers to discover and correct TLS-related configuration problems.
Key considerations
- TLS Configuration Review: Examine your email server's TLS setup for potential misconfigurations and errors highlighted in the reports.
- Gmail Interaction: Focus on resolving any issues that may be affecting secure email communication specifically with Gmail.
- Proactive Problem Solving: Use the information in the reports to proactively identify and fix TLS-related issues, improving email delivery rates.
Expert view
Expert from Word to the Wise explains that TLS reporting helps senders and receivers discover and fix TLS related configuration errors. Google, among others, might be sending these reports because they are trying to alert you to a problem with your email server's TLS setup when interacting with Gmail.
28 Oct 2022 - Word to the Wise
Expert view
Expert from Spam Resource highlights that TLS reporting is crucial for gaining visibility into email delivery issues related to TLS encryption. Receiving these reports from Google indicates they are encountering TLS connection problems when attempting to deliver emails to your domain, suggesting a need to investigate your TLS configuration.
12 Sep 2023 - Spam Resource
What the documentation says
3 technical articles
MTA-STS (Mail Transfer Agent Strict Transport Security) is an internet standard designed to enhance email security. It mandates authentication and encryption during email transmission, preventing attackers from compromising TLS. Google sends reports to domain owners about potential MTA-STS issues to promote better email security. SMTP TLS Reporting, though not strictly MTA-STS, serves a similar purpose by providing insights into TLS connection failures, helping domain owners monitor TLS usage and resolve delivery problems.
Key findings
- MTA-STS Security: MTA-STS requires authentication and encryption for email transmissions, preventing man-in-the-middle attacks.
- Proactive Security: MTA-STS allows mail service providers to declare their support for TLS encryption and authentication, preventing active attackers from subverting TLS.
- Report Purpose: Google sends MTA-STS reports to notify domain owners about potential issues related to MTA-STS implementation and to enhance email security.
- TLS Reporting Function: SMTP TLS Reporting helps identify and resolve email delivery issues by providing insights into TLS connection failures and enabling monitoring of TLS usage.
Key considerations
- MTA-STS Implementation: Consider implementing MTA-STS to strengthen email security by ensuring authentication and encryption.
- Report Analysis: Pay attention to the MTA-STS reports from Google to identify and address potential issues in your email setup.
- TLS Monitoring: Utilize SMTP TLS Reporting to monitor TLS usage and proactively address any connection failures.
- Related Technologies: Understand that MTA-STS and SMTP TLS Reporting are related technologies that contribute to overall email security.
Technical article
Documentation from Red Hat explains MTA-STS is an internet standard that allows mail service providers (MSPs) to declare their support for TLS encryption and authentication in a way that prevents active attackers from subverting TLS.
5 Jun 2025 - Red Hat
Technical article
Documentation from Google explains that MTA-STS (Mail Transfer Agent Strict Transport Security) helps secure email by requiring authentication and encryption during email transmission. Google sends reports to domain owners about potential MTA-STS issues to improve email security.
24 Jul 2023 - Google
Are DMARC RUA and RUF tags mandatory for compliance and what are their benefits?
Are there GDPR concerns related to IP addresses in DMARC reporting?
Can DMARC reports be sent without RUA or RUF addresses?
How can DMARC reports be enriched with user-level data for better domain enforcement?
How can I use DMARC to prevent spammers from using my domain?
How do you analyze DMARC reports using report-uri.com?
