If you manage a business domain or corporate email system, you may have received emails from addresses like noreply@dmarc.yahoo.com with attached files ending in .xml.gz. At first glance, these emails look technical and confusing, leading many users to worry whether something is wrong with their email system or if the message is suspicious.

In reality, these emails are DMARC Aggregate Reports, an important part of modern email security. This article explains what DMARC reports are, why you receive them, what information they contain, and what actions (if any) you need to take.

What Is DMARC?

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol designed to protect your domain from:

• Email spoofing

• Phishing attacks

• Unauthorized use of your domain name

DMARC works on top of two existing mechanisms:

• SPF (Sender Policy Framework)

• DKIM (DomainKeys Identified Mail)

Together, these ensure that only authorized mail servers can send emails on behalf of your domain.

What Is a DMARC Aggregate Report?

A DMARC Aggregate Report is an automated summary report sent by email providers (like Yahoo, Google, Microsoft, etc.) to domain owners.

These reports provide:

• A daily summary of emails sent using your domain

• Information about authentication results

• Visibility into whether emails passed or failed SPF, DKIM, and DMARC checks

The report is sent because your domain’s DMARC DNS record includes an rua= (Reporting URI for Aggregate reports) tag.

Why Are You Receiving This Email?

You receive this email because:

1. Your domain has a DMARC record configured.

2. Your email address is mentioned in the rua tag of that DMARC record.

3. Yahoo received emails claiming to be from your domain and generated a report.

This is normal and expected behavior.

Understanding the .xml.gz Attachment

The attached file:

• Is a compressed XML file

• Contains machine-readable data

• Is meant for analysis, not manual reading

Inside the report you’ll find:

• Sending IP addresses

• Number of emails sent

• SPF result (pass/fail)

• DKIM result (pass/fail)

• DMARC alignment status

• Email provider details

This file is safe, not malware, and not spam.

Is This a Warning or Error?

No.
A DMARC aggregate report:

• Is not a complaint

• Is not an error

• Does not mean emails are failing

• Does not indicate hacking

It is purely informational.

Why DMARC Reports Are Important

DMARC reports help you:

• Detect unauthorized email sending

• Identify spoofing or phishing attempts

• Ensure your SPF and DKIM records are correctly configured

• Improve email deliverability

• Build trust with email providers

For businesses, DMARC reports are a critical cybersecurity monitoring tool.

Should You Take Any Action?

Option 1: Ignore (Acceptable for Small Businesses)

If:

• Emails are working fine

• No delivery issues are reported
  You can safely ignore these emails.

Option 2: Analyze the Reports (Recommended)

You can upload the .xml.gz file to tools such as:

• Google Admin Toolbox (DMARC viewer)

• MXToolbox

• dmarcian

• Postmark DMARC Analyzer

These tools convert technical data into readable dashboards.

Option 3: Stop Receiving Reports

If you don’t want these emails:

• Edit your DMARC record

• Remove or change the rua= email address

Example:

v=DMARC1; p=none;

⚠️ Note: Removing reports reduces visibility into email abuse.

DMARC Policy Levels Explained

• p=none → Monitoring only (no action)

• p=quarantine → Suspicious emails go to spam

• p=reject → Unauthorized emails are blocked

Most domains start with p=none, then gradually move to quarantine or reject.

Common Misconceptions

Best Practices for Businesses

• Always configure SPF, DKIM, and DMARC together

• Monitor DMARC reports monthly

• Use a professional email provider

• Move to p=reject once confident

• Never ignore spoofing warnings in reports

Conclusion

Receiving emails from noreply@dmarc.yahoo.com is a positive sign. It means your domain is protected, monitored, and compliant with modern email security standards. DMARC aggregate reports give you insight into how your domain is used across the internet and help prevent phishing, fraud, and email abuse.

Instead of worrying, consider these reports as a security health report for your domain.

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