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TLS Monitoring

Detect email misconfigurations
before they cause delivery failures

TLS-RPT monitoring and MTA-STS hosting give you visibility into encrypted mail delivery — know when TLS fails, when certificates expire, and when connections are downgraded.

TLS-RPT Monitoring

TLS connection reports,
visualized

TLS-RPT (TLS Reporting) is a standard that lets receiving mail servers send you reports about TLS connection successes and failures. Without it, you have no way to know when email encryption is breaking down between servers.

DMARC Report collects, parses, and visualizes these reports so you can quickly identify which connections are failing and why — certificate issues, protocol mismatches, or configuration errors.

app.dmarcreport.com / tls-rpt
98.4%
TLS Success
1.6%
TLS Failed
12,847
Total Connections
gmail-smtp-in.l.google.com
8,241 connections
TLS 1.3 success
mx1.outlook.com
3,102 connections
TLS 1.2 success
mail.legacy-server.net
204 connections
TLS none failure
testing
Monitoring

TLS is attempted but failures are allowed. Reports are collected to identify issues before enforcing.

enforce
Enforcing

Receiving servers must use TLS. Connections without encryption are rejected, protecting mail in transit.

none
Disabled

No MTA-STS policy published. Connections may or may not use TLS depending on the receiving server.

MTA-STS Hosting

Enforce TLS encryption
on inbound email

MTA-STS (Mail Transfer Agent Strict Transport Security) tells sending servers that your domain requires TLS encryption for email delivery. Without it, connections can silently fall back to unencrypted transmission.

MTA-STS requires hosting a policy file at a specific HTTPS URL on your domain. DMARC Report handles this hosting for you — no need to configure a web server or manage certificates.

  • Policy file hosted and managed automatically
  • No separate web server or certificate required
  • Start in testing mode, move to enforce when ready
  • Works alongside DANE for maximum protection
How It Works

MTA-STS in three steps

1

We host your MTA-STS policy file

DMARC Report hosts the required .well-known/mta-sts.txt file on your behalf. No need to configure a separate web server for your domain.

2

Receiving servers check the policy

When a server receives email for your domain, it looks up your MTA-STS policy to determine whether TLS is required for delivery.

3

Connections without TLS are rejected

In enforce mode, servers that cannot establish a TLS connection will not deliver the email, protecting your messages from interception.

Detection

What we detect

TLS-RPT and MTA-STS monitoring surfaces problems that are otherwise completely invisible — issues that silently break encryption or block delivery.

Delivery failures

Identify when legitimate email cannot be delivered due to TLS negotiation problems between mail servers.

Encryption issues

Detect connections falling back to unencrypted transmission, exposing email content to interception.

Policy violations

Know when receiving servers ignore your MTA-STS policy and establish connections that violate your encryption requirements.

Certificate problems

Get alerted about expired, mismatched, or untrusted TLS certificates that prevent secure mail delivery.

Downgrade attacks

Detect when a man-in-the-middle strips TLS from connections, attempting to intercept email content in transit.

Configuration drift

Monitor your MTA-STS policy file and TLS-RPT DNS records for unexpected changes that could weaken your posture.

Get visibility into TLS delivery

Start your free trial — enable TLS-RPT monitoring and MTA-STS hosting in minutes.

Start Free Trial

What Teams Say About Our Monitoring

G2 Leader — DMARC

Rated 4.8/5 on G2 · 469 verified reviews

G2 Momentum Leader — DMARC
ZK

Zunaid K.

Director

5/5

"Essential tool for email delivery"

This tool helps us to implement DMARC reporting for our domains in an easy to use manner.

8/8/2024 Verified on G2
VU

Verified User in Information Technology and Services

5/5

"Best security tool for your own domains"

The weekly reports help me a lot to analyze quickly the emails sent from my domains and that gives me peace of mind.

8/31/2022 Verified on G2
LH

Larry H.

Research & Development Manager

5/5

"Good tool to buy"

I have used many tools for monitoring DMARC reports. But DMARC Report is a good tool to use. It helps avoid sending emails to spam.

8/30/2022 Verified on G2