What is DMARC?
Domain-based Message Authentication, Reporting, and Conformance (DMARC) is an email authentication protocol designed to combat email fraud and phishing attacks. By verifying email senders and providing detailed reports on email activity, DMARC helps organizations improve email security and protect their domain reputation. It enables domain owners to set specific policies for how their emails should be authenticated and how to handle unauthorized messages. Essentially, DMARC allows companies to say:
“Emails from our domain must meet these specific criteria. If they don’t, they should be treated as suspicious.”
DMARC builds on two existing protocols, SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail), to ensure that only authorized senders can use a domain. Organizations can use DMARC to specify actions for emails that fail authentication, such as rejecting, quarantining, or delivering them.
What Does DMARC Stand For?
DMARC stands for Domain-based Message Authentication, Reporting, and Conformance.
Each part of the acronym reflects a critical aspect of how DMARC works:
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 checks.
Why is DMARC Important in Email Security?
DMARC plays a critical role in enhancing email security by:
- Preventing email spoofing and phishing: By verifying the authenticity of emails claiming to originate from a specific domain, DMARC effectively thwarts spoofing attempts where attackers impersonate legitimate senders. This helps prevent phishing attacks that aim to steal sensitive information like login credentials and financial data.
- Improving email deliverability: By ensuring that only legitimate emails from your domain reach inboxes, DMARC reduces the chances of your legitimate emails being flagged as spam. This improves your email deliverability rates and ensures that your messages reach the intended recipients.
- Protecting your brand reputation: By preventing unauthorized use of your domain for malicious activities, DMARC safeguards your brand’s reputation and builds trust with your customers.
- Providing valuable insights: DMARC generates comprehensive reports that provide valuable insights into your email sending activity. These reports help you identify and address potential issues like unauthorized senders, spoofing attempts, and compromised accounts.
- Meeting industry compliance requirements: DMARC is becoming increasingly important for compliance with industry standards such as PCI-DSS. Major email providers like Google and Yahoo may even reject emails from domains that lack DMARC implementation.
By implementing and maintaining a robust DMARC policy, businesses can significantly enhance their email security posture, protect their brand reputation, and ensure the effective delivery of legitimate email communications.
Simplify DMARC with PowerDMARC!
How DMARC Works
DMARC enhances email security by adding a layer of policy enforcement on top of existing authentication methods: SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail).
1. Assess Your Email Infrastructure:
- Configure SPF and DKIM: Begin by setting up SPF and DKIM records in your DNS settings. These records define which IP addresses and domains are authorized to send emails on behalf of your domain. You can use our SPF and DKIM record generators to assist with this process.
2. Create a DMARC Record:
- Create a DMARC record using our free tool or your DNS provider’s interface.
- The mandatory fields in the DMARC record include:
- v=DMARC1: Specifies the DMARC protocol version.
- p=none/quarantine/reject: Defines the policy for handling emails that fail authentication checks.
- You can also include optional fields such as:
- rua: Specifies the email address for receiving aggregate reports.
- ruf: Specifies the email address for receiving forensic reports.
3. 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”.
- p=none: Monitor authentication results without taking any action. This allows you to analyze your email traffic and identify potential issues.
- p=quarantine: Move emails that fail authentication checks to the spam folder.
- p=reject: Block and discard emails that fail authentication checks.
4. Publish Your DMARC Record:
- Publish the generated DMARC record in your DNS settings. Enter “_dmarc” in the Host field and resource type as TXT. You can keep your TTL at 1 hour.
5. Verify Your DMARC Setup:
- Use our DMARC checker tool to verify that your DMARC record is correctly published and functioning as expected.
5. Reporting:
- Once DMARC is set up, you can activate reporting.
- DMARC generates reports on email authentication results, providing insights into:
- Successful and failed authentication attempts
- Sources of unauthenticated emails
- Actions taken by receiving servers
DMARC Workflow after it’s Published
Once a DMARC record is published:
- Email Sending: When an email is sent from your domain, it undergoes SPF and DKIM checks.
- Email Reception: The receiving server performs the following checks:
- SPF Check: Verifies if the sending IP address is authorized to send emails on behalf of your domain.
- DKIM Check: Verifies the digital signature to ensure the email hasn’t been tampered with.
- DMARC Policy Enforcement: The receiving server checks the DMARC record and applies the specified policy:
- Pass: If the email passes both SPF and DKIM checks, it is delivered normally.
- Fail: If the email fails either SPF or DKIM checks, the receiving server takes the action defined in the DMARC policy (e.g., quarantine, reject).
- Reporting: The receiving server generates reports on email authentication results and sends them to the addresses specified in the DMARC record.
What does DMARC Record Look Like?
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:dmarc@example.com; ruf=mailto:forensics@example.com; 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.
DMARC, SPF, and DKIM – Pillars of Email Security
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:
- 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.
- 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.
- 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.
- 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.
- 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.
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.
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:
- Configure hosted DMARC and other email authentication protocols easily
- Monitor your authentication results through simplified, human-readable reports
- Get real-time alerts on email, slack, discord, and webhooks
- 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.
DMARC FAQs
- How to Fix DKIM Failure - January 9, 2025
- What Is DMARC Policy? None, Quarantine And Reject - January 9, 2025
- How to Fix “No DMARC Record Found” in 5 Easy Steps - January 6, 2025