What Is a DMARC Record and How Does It Work?

Have you ever received an email that looked like it came from a trusted company, only to realize later it was fake?

Email spoofing and phishing attacks have become increasingly common, making it difficult for recipients to know which emails are legitimate. At the same time, businesses struggle to protect their domains and maintain strong email deliverability.

This is where DMARC comes in.

If you've been asking what is DMARC, what is a DMARC record, or what is DMARC in email, you're in the right place.

In this guide, you'll learn:

• What DMARC is and why it matters
• How a DMARC record works
• The relationship between DMARC, SPF, and DKIM
• The different DMARC policies you can use
• How to set up DMARC for your domain

What Is DMARC?

Let's start with the basics.

DMARC (Domain-based Message Authentication, Reporting, and Conformance) is an email authentication protocol that helps protect your domain from spoofing, phishing, and unauthorized email use.

When someone asks "DMARC what is it?", the simplest answer is this:

DMARC tells receiving mail servers how to handle emails that claim to come from your domain but fail authentication checks.

It acts as a security layer that verifies whether an email is truly sent by an authorized sender before it reaches the recipient's inbox.

Without DMARC, cybercriminals can impersonate your domain and send fraudulent emails that appear legitimate.

What Is a DMARC Record?

Now that you know what is DMARC, let's understand what a DMARC record actually is.

A DMARC record is a TXT record added to your domain's DNS settings.

This record contains instructions that tell receiving mail servers:

• How to verify emails sent from your domain
• What to do when authentication fails
• Where to send authentication reports

Think of it as a rulebook that defines how email providers should treat messages claiming to come from your domain.

A typical DMARC record looks something like this:

v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com;

Each part of the record serves a specific purpose, which we'll explore shortly.

What Is DMARC in Email Security?

To understand what is DMARC in email, you first need to understand the problem it solves.

Email was originally designed without strong sender verification.

As a result, attackers can easily forge sender addresses and impersonate trusted brands.

DMARC helps solve this by ensuring that emails pass authentication checks before being accepted by receiving mail servers.

When DMARC is implemented correctly, it helps:

• Prevent email spoofing
• Reduce phishing attacks
• Improve email deliverability
• Protect brand reputation
• Increase recipient trust

For businesses that rely heavily on email communication, DMARC has become an essential security measure.

How Does DMARC Work?

Now that you understand what DMARC is, the next question is: how does it actually work?

DMARC doesn't authenticate emails on its own. Instead, it works alongside two existing email authentication protocols: SPF and DKIM.

Think of SPF and DKIM as security checks, while DMARC acts as the decision-maker that determines what should happen when an email fails those checks.

SPF (Sender Policy Framework)

SPF helps verify whether an email was sent from an authorized mail server.

Every domain can publish an SPF record in its DNS settings that lists the servers allowed to send emails on its behalf.

When a receiving mail server gets an email, it compares the sending server's IP address with the list defined in the SPF record.

If the server is approved, the SPF check passes. If not, the email fails SPF authentication.

For example, if your company uses Google Workspace to send emails, your SPF record tells mailbox providers that Google's servers are authorized to send emails from your domain.

DKIM (DomainKeys Identified Mail)

DKIM adds another layer of protection.

Instead of checking where the email came from, DKIM verifies that the message hasn't been modified after it was sent.

When an email is sent, the sending server attaches a unique digital signature to the message.

The receiving server uses a public key stored in your DNS records to validate that signature.

If the signature matches, the email passes the DKIM check. If someone altered the email content during transit, the signature would no longer match, causing the authentication check to fail.

How DMARC Uses SPF and DKIM

DMARC sits on top of SPF and DKIM and evaluates their results.

When an email reaches a recipient's inbox, the receiving mail server follows this process:

1. The email arrives claiming to be from your domain.
2. The server checks whether the email passes SPF authentication.
3. The server checks whether the email passes DKIM authentication.
4. DMARC verifies that the domain used in SPF or DKIM aligns with the domain shown in the "From" address.
5. If authentication passes, the email is delivered normally.
6. If authentication fails, DMARC applies the policy you've defined, such as monitoring, quarantining, or rejecting the email.
7. The receiving server sends DMARC reports back to the domain owner, providing visibility into authentication results and potential abuse attempts.

A Simple DMARC Example

Imagine a hacker tries to send an email pretending to be from your company domain.

The email reaches the recipient's mail server, which immediately checks SPF and DKIM.

Since the hacker isn't using an authorized server and doesn't have access to your DKIM signing keys, both authentication checks fail.

DMARC then evaluates the results and follows the policy you've configured.

If your policy is set to p=reject, the email is blocked before it ever reaches the recipient's inbox.

This process helps protect your domain from spoofing attacks while ensuring that legitimate emails continue to be delivered successfully.

Understanding DMARC Policies

One of the most important parts of a DMARC record is the policy setting.

The policy tells receiving mail servers what action to take when an email fails authentication.

p=none

This policy monitors email activity without blocking messages.

It's commonly used during initial DMARC implementation.

Benefits include:

• Visibility into email authentication results
• No impact on email delivery
• Easy troubleshooting

p=quarantine

Failed emails are delivered to spam or junk folders.

This policy offers stronger protection while still allowing administrators to monitor potential issues.

p=reject

Failed emails are rejected completely.

This is the strongest DMARC policy and provides the highest level of protection against spoofing attacks.

Key Components of a DMARC Record

A DMARC record contains several tags that define its behavior.

Version Tag (v)

Specifies the DMARC version.

Example:

v=DMARC1

Policy Tag (p)

Defines how failed emails should be handled.

Examples:

p=none

p=quarantine

p=reject

Reporting Address (rua)

Specifies where aggregate DMARC reports should be sent.

Example:

rua=mailto:dmarc@example.com

Forensic Reports (ruf)

Specifies where detailed failure reports should be delivered.

Example:

ruf=mailto:dmarc@example.com

Together, these tags help organizations monitor and enforce email authentication policies.

How to Set Up a DMARC Record

Setting up DMARC isn't as complicated as it may seem. Once you have SPF and DKIM configured, creating a DMARC record is usually a straightforward process.

Follow these steps to implement DMARC for your domain.

Step 1: Configure SPF

Before setting up DMARC, make sure your domain has a valid SPF record.

An SPF record specifies which mail servers are authorized to send emails on behalf of your domain. This helps receiving mail servers verify that your emails come from trusted sources.

Step 2: Enable DKIM

Next, enable DKIM signing through your email service provider.

DKIM adds a digital signature to every outgoing email, allowing receiving servers to verify that the message hasn't been altered during transit.

Most email providers, including Google Workspace and Microsoft 365, offer DKIM configuration within their admin settings.

Step 3: Create a DMARC Record

Once SPF and DKIM are active, create your DMARC record.

It's recommended to start with a monitoring policy so you can analyze email authentication results without affecting email delivery.

v=DMARC1; p=none; rua=mailto:dmarc@example.com

In this example:

• v=DMARC1 specifies the DMARC version.
• p=none enables monitoring mode.
• rua defines where aggregate DMARC reports should be sent.

Step 4: Publish the Record

Add the DMARC record as a TXT record in your domain's DNS settings.

The record is typically published under:

_dmarc.yourdomain.com

Once published, mailbox providers can start applying your DMARC policy to emails sent from your domain.

Step 5: Monitor DMARC Reports

After publishing the record, regularly review the reports sent to your designated email address.

These reports provide insights into:

• Which servers are sending emails on your behalf
• SPF and DKIM authentication results
• Potential spoofing attempts
• Email configuration issues that need attention

Monitoring reports helps you identify problems before enforcing stricter policies.

Step 6: Move to Stronger Policies

After confirming that legitimate emails consistently pass SPF and DKIM checks, you can strengthen your DMARC policy.

The usual progression is:

p=none

to

p=quarantine

and eventually:

p=reject

A quarantine policy sends suspicious emails to spam folders, while a reject policy blocks them entirely.

Gradually moving through these stages helps ensure legitimate emails continue reaching recipients while providing maximum protection against phishing and domain spoofing attacks.

Final Thoughts

Understanding what is DMARC and how it works is becoming increasingly important as email-based threats continue to grow.

A properly configured DMARC record helps protect your domain from spoofing attacks, improves email security, and gives mailbox providers greater confidence in the emails you send. 

More importantly, it helps ensure that legitimate messages reach your recipients instead of being flagged as suspicious.

While setting up DMARC requires SPF and DKIM to be in place first, the long-term benefits far outweigh the initial effort. 

Starting with a monitoring policy, reviewing reports, and gradually moving to stricter enforcement allows you to strengthen your domain's protection without disrupting email delivery.

If your business relies on email for customer communication, marketing, or sales outreach, implementing DMARC is no longer optional—it's a critical step toward building a more secure and trustworthy email ecosystem.

Frequently Asked Questions

Can I use DMARC without SPF or DKIM?

No. DMARC relies on SPF and/or DKIM authentication results. Before implementing DMARC, you should configure at least one of these protocols, though using both provides the strongest protection.

How do I check if my domain has a DMARC record?

You can check your DMARC configuration using DNS lookup tools, email authentication analyzers, or online DMARC checkers. These tools will show whether a DMARC record exists and if it is configured correctly.

How long does it take to set up DMARC?

For most businesses, creating and publishing a DMARC record takes only a few minutes. However, monitoring reports and moving to stricter enforcement policies may take several weeks depending on your email infrastructure.

What happens if an email fails DMARC authentication?

The action depends on your DMARC policy. The email may be monitored, sent to the recipient's spam folder, or rejected entirely based on whether your policy is set to none, quarantine, or reject.