What is DMARC? A Complete Guide to DMARC Email Protection

What is DMARC?

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication protocol that verifies email senders and provides insights for enhanced email security. It allows domain owners to set up domain-level policies on mail handling. DMARC is a way to fix challenges like phishing and spam. It lets companies say “Emails from us will have these specific qualities. If an email claiming to be from us doesn’t have those qualities, it’s fake.” This includes setting up preferences for message verification, failure responses, and reporting. DMARC is described under RFC 7489 of the Internet Engineering Task Force (IETF).

Technically, DMARC is intended to help combat email fraud and phishing attacks. It does so by allowing email recipients to determine the authenticity of a message using SPF and DKIM protocols. Based on the results of the verification, domain owners can reject, quarantine, or deliver the email. All these functions are controlled by DNS-level instructions that are uploaded by the domain owner himself.

DMARC Full Form

You can learn a lot about DMARC/ Domain-based Message Authentication, Reporting, and Conformance by breaking down the components of “DMARC” acronym:

Domain-based: DMARC runs at the domain level.

Message Authentication: DMARC allows domain owners to designate the authentication protocols. These are used to validate incoming email messages. SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) are two such protocols.

Reporting: You can enable feedback reports within your DMARC configuration. Following this, receiving MTAs will send over XML reports to your defined email address. These reports may contain DMARC aggregate or forensic data.

Conformance: Email domain owners can use DMARC to describe the actions of receiving mail servers in the form of policies. These actions are implemented once an email fails the DMARC checker.

What Does DMARC Stand For?

DMARC stands for Domain-based Message Authentication, Reporting, and Conformance. To understand the role of DMARC and how it works, you need to first understand the core issues it addresses. Cybercriminals utilize sophisticated techniques to craft deceptive emails by impersonating real domains in the following ways:

1. Phishing. A scammer can send you an email pretending to be your bank, asking you to log in to your account. If you fall for it, they steal your credentials. Fraudulent email and phishing pose significant challenges to business email communications.
   In 2024, the Anti-Phishing Working Group (APWG) reported 877,536 phishing attacks in Q2 alone. And phishing can lead to financial losses–the total amount of wire transfer requests made in Q1 2024 was $89,520–data breaches, and damage to your brand reputation or your emails.
2. Spam. Spammers can blast out millions of emails pretending to be from legitimate companies. At the same time, your legitimate emails may also land in spam folders if not authenticated with DMARC.

Both of these problems stem from the fact that it’s trivially easy to fake the “From” address on an email. There’s no built-in way for the recipient to know if an email is really from who it claims to be from. DMARC is a remedy for this situation.

Simplify DMARC with PowerDMARC!

The Foundation: SPF and DKIM

To fully understand what DMARC is, we also need to look at its building blocks: SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail).

SPF: SPF authentication protocol allows domain owners to specify which IP addresses are authorized to send emails on behalf of their domain. It’s like a guest list for a party, where only those on the list are allowed in.

DKIM: This method adds a digital signature to emails. It’s like sealing a letter with wax in the old days. It proves the email message hasn’t been tampered with since it left the authorized server.

DMARC builds upon these, adding a policy layer that tells receivers what to do with messages that fail authentication.

How Does DMARC Work?

Here’s how DMARC works:

1. The company sets up some technical stuff on their end—specifically, they go into their DNS settings, and set up DNS records to configure SPF and/or DKIM. These are ways of authenticating emails.
2. The company publishes a DMARC record with a DMARC policy. This is just a short text record that says “Our legitimate emails will pass SPF and/or DKIM checks.”
3. If either check passes, the message is termed as “DMARC PASS”; if both fail, the message fails DMARC authentication (since it didn’t meet SPF or DKIM requirements).
4. Depending on the DMARC policy configured, the message can now be rejected or discarded, flagged as spam or quarantined, or delivered as is.

For instance, the company can publish a DMARC policy, “If incoming mail claiming to be from us fails those checks, here’s what you should do with it.”

The “what you should do with it” part can be:

1. Do nothing (useful when you’re just starting out with DMARC)
2. Put it in the spam folder
3. Reject it entirely

Once your DMARC domain alignment is set up, you can enable DMARC reports. This helps email senders identify suspicious messages so you can take action against them quickly—and keep your subscribers safe.

Why is DMARC Important?

DMARC plays a pivotal role in scaling your email security efforts. While email systems have spam filters in place, these are not effective against direct-domain spoofing attacks. By impersonating companies, attackers can retrieve login credentials to sensitive information. In fact, IBM’s Cost of a Data Breach Report found that compromised credentials led to 19% of all data breaches.

Moreover, visibility through report-based feedback is a DMARC feature that truly stands out.

Here are some more features that highlight the importance of DMARC:

• It ensures email authentication
• It protects from domain spoofing
• It protects against phishing attacks
• It is mandatory for Google & Yahoo bulk senders
• It is mandatory for PCI-DSS compliance
• BIMI Requires DMARC Enforcement

Benefits of DMARC

DMARC benefits a company/business by helping them prevent impersonation attacks. It also has long-term capabilities of reducing spam and deliverability issues. Moreover, DMARC has been made mandatory by various major ESPs. Yahoo and Google inboxes can now even reject emails that do not have DMARC implemented. Hence, to stay compliant, configuring the protocol is highly recommended.

Here are some of the benefits of implementing DMARC:

• Email Fraud Prevention: You can prevent phishing attacks by using DMARC Reports. They help identify spoofed emails and sources that may be impersonating you.
• Improves Brand Reputation: You can improve your brand reputation by ensuring that only legitimate messages are delivered to your recipients.
• Minimizes Spam: You can reduce the amount of spam in your customer’s inboxes by preventing fraudulent messages from reaching them in the first place.
• Provides Visibility: Quickly identify who is sending emails on your behalf without your knowledge using reports.
• Improves Deliverability: Enables domain owners to improve their email’s deliverability rate by 10% over time by deploying the protocol correctly for your emails.

How to Implement DMARC for Your Domain

Setting up DMARC can be a bit technical and we have covered it in detail in our DMARC setup guide. Here are the general steps involved:

1. Assess Your Email-Sending Infrastructure

Make a note of marketing automation platforms, customer service tools, and email delivery services.

2. Configure SPF or DKIM Records

If your emails pass either SPF or DKIM checks, they will be considered DMARC compliant. You can use our SPF record generator and DKIM record generator tools to create these records.

Publish the generated records on your DNS with the help of your DNS registrar.

3. Create a DMARC TXT Record

You can sign-up with PowerDMARC for free to create your record using our DMARC record generator tool. The mandatory fields include protocol version “v”, which is always DMARC1, and the policy mode “p” can be configured according to your preference.

4. Select a DMARC policy

DMARC policy tells email receivers how to handle messages that fail DMARC checks. You can choose between three policy modes – “none”, “quarantine” or “reject”.

1. None (p=none): This is essentially a monitoring mode. Emails that fail DMARC checks are still delivered, but the domain owner receives reports. It’s like having a security camera that records but doesn’t stop intruders.
2. Quarantine (p=quarantine): Emails that fail DMARC are treated as suspicious. They might be sent to the spam folder or held for further review. It’s similar to a bouncer at a club who doesn’t immediately turn away suspicious individuals but keeps them in a holding area.
3. Reject (p=reject): This is the strictest policy. Emails that fail DMARC are outright rejected. It’s like a strict “no entry” policy at an exclusive event.

Optional (but recommended) fields: 

• Alignment requirements: You can specify the alignment requirements for your domain’s SPF and DKIM records. This means that the domain name in the “From” header of an email may/may not exactly match the domain name in the SPF and/or DKIM record.
• Reporting: As discussed earlier, you can configure DMARC to receive reports on your email address or a third-party service. These reports will provide information on email activity. Including the number of emails sent, and the number of emails that passed/failed authentication checks.

5. Publish Your DMARC Record

You will need to access your DNS management console to publish your record. Enter “_dmarc” in the Host field and resource type as TXT. You can keep your TTL at 1 hour.

6. Verify Your DMARC Setup

Check your DMARC implementation with the help of our DMARC checker tool. Just enter your domain name and click on “lookup” to check if your record is valid.

DMARC in Action: A Step-by-Step Process

1. Publishing the DMARC Record: The domain owner creates a DMARC record in their DNS. This record contains instructions for receivers on how to handle emails from their domain.
2. Sending an Email: When an email is sent, it goes through the usual channels.
3. Receiving the Email: The receiving server performs several checks:
   •  It verifies SPF by checking if the sending IP is authorized.
   •  It verifies DKIM by checking the digital signature.
   •  It checks the “From” header to ensure it matches the domain used in SPF/DKIM.
4. DMARC Policy Check: The receiver then checks the sender’s DMARC policy.
5. Action Based on Policy: Depending on the policy (none, quarantine, or reject), the receiver takes appropriate action.
6. Reporting: The receiver generates reports about emails processed and sends them back to the domain owner.

What is a DMARC Record?

The structure of a DMARC record is defined in the DNS (Domain Name System) as a TXT record associated with the domain. It contains several tags including ones that specify the policy mode and reporting options. Here’s an example of what a DMARC record might look like:

_dmarc.example.com. IN TXT v=DMARC1; p=reject; rua=mailto:[email protected]; ruf=mailto:[email protected]; sp=reject;

In this example:

• “_dmarc.example.com.” refers to the specific domain where the DMARC record is being set up. In this case, it is “example.com.”
• “IN TXT” indicates the record type as a text record.
• “v=DMARC1” signifies that the version of the protocol being used is version 1.
• “p=reject” sets the DMARC policy to “reject”. This instructs receiving email servers to reject or discard emails that fail DMARC.
• “rua=mailto:” specifies the email address as the destination to receive aggregate reports.
• “ruf=mailto:” designates the email address as the destination to receive forensic reports. These reports provide more information on email delivery failures.
• “sp=reject” sets the subdomain policy to “reject,” ensuring that this DMARC policy applies to subdomains.

The Power of DMARC Reports

One of DMARC’s most valuable features is its reporting capability. Domain owners receive two types of reports:

Aggregate Reports

These provide a high-level overview of email traffic, including:

•  IP addresses sending emails on behalf of the domain
•  Whether these emails passed SPF and DKIM
•  What actions were taken based on the DMARC policy

Forensic Reports

These offer detailed information about specific authentication failures, including:

• Email headers
• URLs found in the message body
• Attachment details

These reports offer a lot of visibility into a domain’s email activity, helping identify legitimate and illegitimate sources of email.

DMARC, SPF, and DKIM – Pillars of Email Authentication

Implementing DMARC, SPF, and DKIM together provides a more robust defense against email spoofing and phishing attacks. Let’s explore the benefits of using these authentication methods in combination:

1. Comprehensive Protection: The combination of DMARC, SPF, and DKIM provides a layered approach to email authentication. It offers comprehensive protection against email spoofing, phishing, and unauthorized senders.
2. Enhanced Email Deliverability: By ensuring that emails are properly authenticated and aligned with domain policies, the chances of legitimate emails being marked as spam or rejected are significantly reduced.
3. Brand Reputation Protection: Implementing these authentication methods helps maintain the integrity of your brand. They prevent email abuse and spoofing, safeguarding your reputation among recipients.
4. Improved Security: The use of DMARC, SPF, and DKIM together minimizes the risk of unauthorized entities sending malicious emails on behalf of your domain, strengthening overall security and mitigating potential cyber threats.
5. Reporting and Visibility: DMARC provides valuable reporting insights into email authentication failures, allowing domain owners to identify and address issues promptly, and enhancing the effectiveness of their email security measures.

Should you use SPF and DKIM if you already have DMARC?

Yes, it is highly recommended to use both SPF and DKIM even if you have already implemented DMARC email validation protocol. DMARC is designed to work alongside SPF and DKIM, and together they form a powerful email authentication framework. However, for DMARC to function, either SPF or DKIM is needed.

Implementing DMARC: Best Practices

For organizations looking to implement DMARC, adopt the following practices to ensure you’re getting maximum benefits:

• Start with an Audit: Understand your current email infrastructure, including all services sending email on your behalf.
• Implement SPF and DKIM: Ensure these are correctly set up before moving to DMARC.
• Begin with Monitoring: Start with a “p=none” policy to gather data without affecting email delivery.
• DMARC Analyzer for Reports: Regularly review DMARC reports to understand your email ecosystem and identify potential issues.
• Gradually Increase Policy Strictness: Move to “p=quarantine” and eventually “p=reject” as you gain confidence in your setup.
• Communicate: Ensure all stakeholders, including IT, marketing, and third-party vendors, are aware of your DMARC implementation plans.
• Stay Informed: Keep up with developments in email authentication standards and best practices.

DMARC Challenges and Considerations

While DMARC is powerful, it’s not without challenges:

• Complexity: Implementing DMARC correctly requires a good understanding of email infrastructure and DNS.
• Third-party Senders: Many organizations use third-party services to send emails (e.g., marketing platforms). Ensuring these align with DMARC can be tricky.
• Email Forwarding: Forwarding emails can break DMARC authentication. This is because the forwarding server often modifies the email in ways that invalidate the original DKIM signature and SPF header information.
• Gradual Implementation: Moving too quickly to a strict policy can result in legitimate emails being blocked. It’s crucial to start with a monitoring policy and gradually increase strictness.

The Future of Email Authentication

As cyber threats evolve, so too must our defenses. DMARC is a significant step forward, but it’s part of a broader ecosystem of email security measures. Future developments might include:

• Integration with AI: Using machine learning to better interpret DMARC reports and identify patterns of abuse.
• Enhanced User Interfaces: Making DMARC results more visible to end-users, perhaps with visual indicators of email authenticity.
• Broader Adoption: As more organizations implement DMARC, its effectiveness in combating email fraud will increase.
• Evolution of Standards: The email authentication landscape continues to evolve. We may see new standards emerge that build upon or complement DMARC. Other technologies like DANE and MTA-STS are also being developed to further secure email.

PowerDMARC’s Cloud-Based DMARC Solution

As a business owner maintaining an online domain, having DMARC implemented serves as a feather in your cap in terms of security. While you can do so manually, there are certain additional benefits of choosing a third-party vendor like PowerDMARC. With us, you get a host of reporting, management, and monitoring facilities at a very affordable rate. These don’t fall within the scope of a manual DMARC setup and can really make a difference for your business!

By configuring our DMARC analyzer you can:

1. Configure hosted DMARC and other email authentication protocols easily
2. Monitor your authentication results through simplified, human-readable reports
3. Get real-time alerts on email, slack, discord, and webhooks
4. Improve your email deliverability over time

Our customers enjoy dedicated support from our in-house DMARC experts to configure the solutions tailored to their needs. Get in touch with us today for a free DMARC trial!

“Extensively searched for a high-value DMARC platform and found it!”

Dylan B.

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• About
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Maitham Al Lawati

Cybersecurity Expert, CEO at PowerDMARC

Maitham is a tech entrepreneur, cybersecurity expert, CEO and Founder of PowerDMARC with 15+ years of industry experience. Maitham holds a Global MBA from the University of Manchester and various professional certifications including CISSP, CISM, CRISC, and ISC2 CCSP.

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