DMARC implementation: How to protect your domain in 6 steps

Email is still the king of business communication. However, that crown comes with a big target on its back. Cybercriminals are constantly finding new ways to exploit email vulnerabilities, leaving many of us wondering: How can we keep our inboxes (and our businesses) safe?

There’s a simple answer: DMARC implementation.

DMARC stands for Domain-based Message Authentication, Reporting, and Conformance, and it builds on SPF and DKIM to create an email security dream team. Together, they give you the power to decide how to handle emails that don’t pass the authentication check.

Unfortunately, implementing DMARC isn’t as simple as just pushing a “start” button. You’ll need a bit more know-how (and perhaps a technical partner) to get your DMARC implementation right.

On the bright side, we can help you with both.

Below, we’ll walk you through everything you need to know about DMARC implementation to better protect your domain and customers.

The basics of DMARC

DMARC works seamlessly with existing protocols to improve your overall email protection. It allows domain owners to specify how to handle unauthenticated emails, effectively giving you control over your email ecosystem.

DMARC has two primary components: SPF and DKIM.

1. SPF (Sender Policy Framework): This protocol specifies which mail servers are authorized to send emails on behalf of your domain.
2. DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to your emails to guarantee they haven’t been altered during transit.

DMARC integrates these two protocols, verifies their results, and then takes action based on the policies you’ve set.

How DMARC works

1. Authentication: When an email arrives, the receiving server checks it against DMARC protocols.
2. Alignment: DMARC checks that the “From” address aligns with the domain that passed SPF or DKIM authentication.
3. Policy enforcement: Based on your specified settings, DMARC directs the server on how to handle emails that fail these checks.
4. Reporting: DMARC provides detailed reports on email traffic using your domain, offering valuable insights into your email ecosystem.

DMARC implementation: Step-by-step process

Now that we’ve covered the basics, it’s time to roll up our sleeves and get into the nitty-gritty of DMARC implementation. We’ll break it down into manageable steps.

Implementing DMARC is like building a house. You need a solid foundation, the right solutions, and a clear plan. Each step builds on the previous one, gradually strengthening your email security.

We’ll walk you through everything from assessing your current email infrastructure to maintaining and optimizing your DMARC policy. Whether you’re a small business owner or part of a large enterprise IT team, these steps will guide you toward stronger, more reliable email authentication.

1. Evaluate your current email infrastructure

Before you start implementing DMARC, you need to understand your current email landscape. This step involves taking stock of your existing email infrastructure and practices.

Start by identifying all sources of legitimate email from your domain. This includes:

• Your primary email servers
• Third-party services that send email on your behalf (e.g., marketing platforms, CRM systems)
• Cloud services using your domain for notifications
• Any other authorized sources of email using your domain

Next, review your existing SPF and DKIM configurations. If you haven’t implemented these yet, don’t worry — we’ll cover that in the next steps. If you have, make sure they’re up to date and properly configured.

Remember, thoroughness at this stage can save you headaches down the line. Take your time, involve all relevant stakeholders, and document everything. This information will be invaluable as you move forward with your DMARC implementation.

2. Implement SPF

Now, it’s time to implement or update your Sender Policy Framework (SPF) record. SPF is an essential component of DMARC — it’s your first line of defense against email spoofing.

To implement SPF:

1. Create your SPF record: This is a TXT record in your domain’s DNS. It lists all the IP addresses and domains authorized to send email on behalf of your domain.
2. Include all legitimate email sources: Refer to the list you created in Step 1. Check that every authorized sender is included in your SPF record.
3. Choose your qualifier: SPF uses qualifiers to tell receiving servers how to handle emails. The most common are: • “+all” (allow all) • “~all” (soft fail) • “-all” (hard fail). For most organizations, “-all” is recommended for the strongest security.
4. Publish your SPF record: Add the completed SPF record to your domain’s DNS.
5. Test your SPF record: Use online SPF check tools to verify your record is correctly formatted and includes all necessary senders.

3. Implement DKIM

With SPF in place, the next step is to implement DomainKeys Identified Mail (DKIM). DKIM adds a digital signature to your emails, providing an additional layer of authentication and integrity.

To implement DKIM:

1. Generate DKIM keys: Create a pair of public and private keys for each domain or subdomain you want to authenticate. Your email server will use the private key to sign outgoing messages.
2. Configure your email servers: Set up your email servers or services to sign outgoing messages with the private DKIM key. This process varies depending on your email infrastructure.
3. Publish your DKIM record: Add a TXT record to your DNS that contains your public DKIM key. This allows receiving servers to verify the signature on your emails.
4. Test DKIM signing: Send test emails to double-check they’re being signed correctly. Many email clients can show DKIM results in the email headers.
5. Implement DKIM for third-party senders: Work with any third-party services that send email on your behalf to guarantee they’re using DKIM. Many services provide their own DKIM keys that you’ll need to add to your DNS.

You may need multiple DKIM keys if you use different email services or subdomains. Each key should have its own DNS record.

4. Create a DMARC record

With SPF and DKIM in place, you’re ready to create and publish your DMARC record. This step ties everything together and sets your DMARC policy.

To create your DMARC record:

1. Choose your initial policy: Start with “p=none”. This monitoring mode allows you to gather data without affecting email delivery.
2. Set up reporting: Include both aggregate (RUA) and forensic (RUF) reporting. These provide valuable insights into your email traffic.
3. Determine your identifier alignment: Decide whether you want strict or relaxed alignment for SPF and DKIM. Relaxed is often a good starting point.
4. Create your DMARC record: A basic DMARC record looks like this: v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com; ruf=mailto:dmarc-reports@yourdomain.com; fo=1
5. Publish your DMARC record: Add this TXT record to your DNS, typically at _dmarc.yourdomain.com.
6. Test your DMARC record: Use online DMARC check tools to verify your record is correctly formatted and published.
7. Monitor initial reports: Start reviewing the reports you receive. These will help you identify any legitimate emails that are failing authentication.

5. Monitor your DMARC reports

With your DMARC record in place, it’s time to dive into the data. Your initial “p=none” policy won’t block or quarantine any emails. It’s simply an observation period that allows you to understand your email ecosystem better and make necessary adjustments before enforcing stricter policies.

To monitor and analyze your DMARC reports:

1. Set up a system to receive reports: Ensure the email address specified in your DMARC record can handle the volume of reports you’ll receive.
2. Understand the two types of reports: 
   1. Aggregate (RUA) reports: These provide an overview of email traffic from your domain.
   2. Forensic (RUF) reports: These offer detailed information about specific authentication failures.
3. Regularly review your reports: Set aside time to analyze these reports, looking for patterns and anomalies.
4. Identify legitimate vs. unauthorized sources: Use the reports to distinguish between authorized senders failing authentication and potential malicious activity.
5. Address authentication failures: Work with legitimate senders to correct SPF and DKIM issues causing authentication failures.
6. Track your progress: Monitor improvements in your authentication rates over time.
7. Consider using DMARC analysis tools: For larger organizations, specialized solutions can help manage and interpret the volume of data in DMARC reports.

Remember, this monitoring phase isn’t just about collecting data — it’s about using that data to improve your email authentication. The insights you gain during this step will guide your decisions as you move toward stricter DMARC enforcement.

6. Gradually increase DMARC enforcement

With a solid understanding of your email ecosystem from monitoring reports, it’s time to start tightening your DMARC policy. This step involves gradually increasing enforcement to improve security while minimizing disruption of legitimate email flow.

To increase DMARC enforcement:

1. Start with a small percentage: Change your policy from “p=none” to “p=quarantine” with a low percentage, e.g., “pct=1”. This applies the policy to only 1% of failed messages.
2. Monitor the impact: Closely watch your reports and user feedback for any issues arising from the new policy.
3. Gradually increase the percentage: Slowly raise the “pct” value over time, continuing to monitor for problems.
4. Move to full quarantine: Once you’re confident in your authentication setup, set “pct=100” for your quarantine policy.
5. Transition to “p=reject”: After a period of successful quarantine enforcement, change your policy to “p=reject”. Again, start with a low percentage and gradually increase.
6. Achieve full rejection: Finally, set your policy to “p=reject” with “pct=100” for maximum protection.

There’s no one-size-fits-all timeline for this process. The pace of policy tightening depends on your organization’s size, complexity, and risk tolerance. Some organizations may complete this process in weeks, while others may take months or even a year.

DMARC implementation best practices

Here are a few additional DMARC implementation best practices that’ll help you maximize the benefits of DMARC while minimizing potential disruptions.

• Start with a pilot domain: Before rolling out DMARC across your entire organization, consider starting with a less critical domain. This allows you to gain experience and iron out any issues without risking disruption to your main email communications.
• Communicate with stakeholders: Keep all relevant parties informed throughout the implementation process. This includes your IT team, management, and any departments that heavily rely on email communications.
• Use a phased approach: Don’t rush to full enforcement. The gradual approach we outlined in the steps above is crucial for identifying and addressing issues before they become problems.
• Regularly review and update: Set a schedule for reviewing your DMARC reports and updating your policies.
• Document everything: Keep detailed records of your implementation process, including any issues encountered and how they were resolved.
• Consider using DMARC management solutions: For larger organizations or complex email setups, specialized DMARC management solutions can help simplify the process of analyzing reports and managing your policies.
• Don’t forget about subdomains: Double-check that your DMARC policy covers subdomains as well. The “sp” tag in your DMARC record can help with this.

Partner with Valimail for your DMARC implementation

DMARC implementation is an ongoing process, not a one-time task. It requires continuous monitoring, adjustment, and optimization to maintain its effectiveness. The benefits, however, are well worth the effort.

Still, that’s a lot of work, and you might not have the time or IT know-how to confidently implement DMARC. Fortunately, you’re not stuck.

Valimail can help.

Valimail provides the guidance and solutions you need to simplify DMARC implementation:

• Automated DMARC management: Our platform automates the DMARC process — from initial setup to ongoing maintenance — saving you time and reducing the risk of configuration errors.
• Comprehensive reporting and analytics: Get clear, actionable insights from your DMARC reports to help you identify and address authentication issues quickly.
• Third-party sender management: We help you navigate the complexities of authenticating emails from your third-party senders for comprehensive coverage.
• Gradual enforcement assistance: Our experts guide you through the process of moving from monitoring to enforcement to minimize disruption to your legitimate email flow.
• Ongoing support and optimization: As your email ecosystem evolves, we’re here to help you maintain and optimize your DMARC implementation for maximum protection.

Ready to get started?

Start getting insights into your DMARC reports with Valimail Monitor (for free), or schedule a demo with our experts to see how we can automate and streamline your DMARC implementation.