Starting May 5, Microsoft will require DMARC.

Check if your domain is compliant.
MTA-STS checker icon

MTA-STS Checker

Check your domain's MTA-STS configuration. Ensure your emails are transmitted securely with TLS encryption and protect against downgrade attacks and message interception.

What is MTA-STS?

MTA-STS (Mail Transfer Agent Strict Transport Security) is an email security standard that enables domain owners to enforce TLS encryption for all incoming emails. It prevents attackers from intercepting email through downgrade attacks or man-in-the-middle techniques.

Enforce TLS Encryption

Require that all mail servers connecting to your domain use TLS encryption, preventing plaintext email transmission.

Prevent Downgrade Attacks

Stop attackers from forcing email delivery over unencrypted connections where they could intercept messages.

Certificate Validation

Verify the validity of TLS certificates presented by mail servers to prevent man-in-the-middle attacks.

Failure Handling

Define how mail servers should handle delivery failures when TLS requirements cannot be met.

MTA-STS Policy Modes

MTA-STS policies can be deployed in different modes depending on your security requirements:

Start here for visibility

Testing Mode

Monitor mode - report failures but deliver messages anyway

Maximum protection

Enforce Mode

Strict mode - reject delivery if TLS requirements aren't met

For policy removal only

None Mode

No policy enforcement - used to remove an existing policy

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How Skysnag Simplifies MTA-STS

Skysnag automates the implementation and management of MTA-STS for your domain, ensuring your emails are always transmitted securely.

Automated Setup

Generate and deploy MTA-STS policies with zero manual configuration

DNS Record Management

Create and maintain the required DNS records for MTA-STS

Policy Hosting

Host your MTA-STS policy file on secure, high-availability servers

TLS-RPT Integration

Seamlessly integrate with TLS-RPT for comprehensive reporting

Gradual Deployment

Safely progress from testing to enforcement mode without disrupting email

Continuous Monitoring

Monitor your MTA-STS policy effectiveness and detect issues

MTA-STS Implementation Results

See the impact of implementing MTA-STS with Skysnag

100%

TLS-encrypted email delivery

98%

reduction in downgrade attacks

24/7

policy monitoring and alerts

99.9%

secure email delivery rate

Talk to an expert to review your authentication gaps.

Meet with one of our experts to review your report. We'll walk you through the issues, explain the security gaps, and show you exactly how Skysnag resolves them - automatically.

Discuss my results

See everything Skysnag has to offer

Skysnag gives you everything you need to enforce DMARC, automate SPF and DKIM, deploy MTA-STS and TLS-RPT, and activate BIMI - so your emails are secure, compliant, and trusted.

Monitor

Identify email compromise attempts and troubleshoot email delivery issues

Comply

Comply with Microsoft, Google and Yahoo requirements and visualize sending data in real-time

Protect

Automate DMARC enforcement for unparalleled email security

Certify

Certify your brand with the highest identity standard globally

Start for free