Understanding DMARC: The Key to Successful Email Delivery

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By cloudcontactai

In today’s technological age, email has replaced many other forms of communication. However, the increasing number of phishing attempts, spam, and email fraud has made it crucial for organizations to ensure the security and authenticity of their email communications. This is where DMARC (Domain-based Message Authentication, Reporting, and Conformance) comes into play. DMARC is a powerful email authentication protocol that helps protect businesses and individuals from email scams while improving email deliverability. 

To begin, let’s define DMARC.

The DMARC (Domain-based Message Authentication, Reporting, and Conformance) email protocol governs the actions taken when a message fails authentication checks (i.e., when the receiving server cannot verify that the sender is who they claim to be). When published for a domain, this protocol takes effect immediately. Messages purportedly transmitted from the sender’s domain are authenticated (through SPF and DKIM) so that receiving organizations can verify the sender’s domain. Messages that do not pass authentication checks (SPF and DKIM) are handled by DMARC. Is Quarantine Necessary? Rejected? or should we allow the message through despite the fact that it has not been able to authenticate itself? To cut a long tale short, DMARC functions as a barrier to inboxes and may avoid malicious code and phishing attacks from reaching the inbox if it is properly configured.

What is the DMARC Record?

Domain-based Message Authentication, Reporting, and Conformance (DMARC) uses Domain Name System (DNS) announcements to specify how incoming email from a certain domain should be processed (i.e., ignored, quarantined, or rejected). Nearly all email systems can figure out how to handle messages purportedly coming from your domain because DNS makes this information readily available. One single DNS adjustment (through a DMARC (TXT) record) is all that’s needed to get it up and running, further simplifying deployment.

How exactly does DMARC function?

When used in combination with SPF and DKIM (the verification tests we mentioned previously), DMARC is a powerful tool for verifying the sender’s identity and taking appropriate action on the message. To put it simply, a DMARC record tells a recipient what to do (i.e., ignore, quarantine, or reject) if they receive questionable email purporting to come from a given sender. Here’s how it operates:

In step one, the domain owner makes a DMARC DNS Record public using their DNS hosting provider.

The second step is for the recipient’s mail server to check for the presence of a DMARC record whenever an email is sent from the domain (or someone impersonating the domain).

Third, the mail server checks the sender’s domain name against a DNS lookup and a DKIM/SPF authentication/alignment check.

  • Is there a valid DKIM-Signature on the message?
  • Does the IP address of the sender correspond to one of the addresses on the SPF record?
  • Do domain alignment tests pass for the message’s headers?

The mail server can then apply the DMARC policy for the transmitting domain based on the DKIM and SPF results. The gist of this rule is as follows:

  • If a message fails DKIM/SPF validation, should I quarantine it, reject it, or do nothing with it?

Fifth, once the receiving mail server (like Gmail) has decided what to do with the message, it will report the outcome of this message and any others from the same domain. The email address or addresses listed in the DMARC record for a domain are the ones that receive these reports, which are known as DMARC Aggregate Reports.

Why is DMARC Required?

It is highly recommended that you adopt the DMARC standard in order to protect your company from fraudulent email activities. Whether you’re an online retailer or run a brick-and-mortar store, email is the major method by which your company communicates with its employees, customers, and vendors. Since it is simple to forge an unencrypted communication, cybercriminals are becoming more and more clever in their attempts to steal your money through various email scams. Together, DMARC’s senders and receivers can better protect email from spoofing, phishing, and spam.

What are the advantages?

When it comes to email security and deliverability, DMARC plays a vital role because it allows for:

  • The ability to see whether or not emails from your domain are being validated with SPF and/or DKIM.
  • Brand Safety – Prevent customers from receiving fraudulent emails that could damage your company’s credibility.
  • Protect your business’s sensitive information by warning users about phishing scams.

Sender Policy Framework – SPF

Using SPF, an ISP (like Gmail, Yahoo!, etc.) may make sure an email service providers server has permission to send on behalf of a certain domain. It’s a list of approved email senders that can be used by other services on your behalf. SPF, like DKIM, is a DNS-based service. You can add a DNS record that specifies Mail Campaign Monitor’s and Gmail’s mail servers as trustworthy sources to send email for your domain if you use both services for sending email. Please note that there should be only one SPF record for each sending domain. The SPF record is updated for each service you utilize by adding “include” directives, as seen above. Verifying who may send email on your domain’s behalf has become increasingly crucial due to SPF’s direct impact on email delivery. You’ll need it for things like support (Zendesk, Helpscout, etc.) or other providers who send email on your behalf, in addition to using it for email marketing or your corporate email accounts. Looking at the message headers will tell you if a message has been signed correctly with DKIM and if it has passed SPF validation. To view the original, click the “Show original” button in your Gmail inbox. 

Where does DMARC fit together with DKIM and SPF?

All of it, really. The action taken by an ISP in response to SPF and DKIM results is entirely discretionary. With DMARC, you may take the results of DKIM and SPF one step further by setting a policy to reject or quarantine emails from senders you do not recognize or trust. PayPal, for one, publishes a DMARC record instructing message rejection if either DKIM or SPF checks out. The ISPs that adhere to this policy will delete any unsuccessful emails. According to an Agari analysis, DMARC prevented almost 25 million attempts against PayPal during the 2013 holiday season. In short, DMARC allows you to instruct ISPs on how to handle situations where neither SPF nor DKIM are available.

How should you respond to DMARC reports?

When using an ISP that supports DMARC, you can get reports on all the sending activity related to your domain. The XML files containing the reports will be sent to the address you entered in your DMARC record. Both SPF and DKIM success or failure, as well as the sender domain and IP address, are included in the reports. This is a great feature of DMARC. Controlling your domain’s email authentication security is a breeze, and you’ll have full insight into who’s sending emails in your name and whether or not they’re using DKIM or SPF.

Implementing DMARC

To implement DMARC successfully, organizations should follow these steps:

Assess the Current Email Infrastructure: Before implementing DMARC, it is crucial to analyze the existing email infrastructure, including SPF and DKIM records, and ensure they are properly configured.

Publish DMARC Records: Organizations need to create and publish DMARC records in their DNS zone files. These records define the DMARC policy and specify how receiving servers should handle unauthenticated messages.

Monitor and Analyze DMARC Reports: Once DMARC is implemented, it’s essential to monitor the generated reports regularly. These reports provide valuable insights into email authentication results, helping organizations identify any issues or anomalies.

Gradual Policy Enforcement: It’s recommended to start with a “none” policy initially, allowing organizations to collect and analyze DMARC reports without impacting email service providers delivery. After gaining confidence in the reports and addressing any issues, the policy can be gradually transitioned to “quarantine” or “reject.”

Ongoing Maintenance and Fine-tuning: DMARC implementation is not a one-time task. Organizations should regularly review and update their DMARC policies based on the insights gained from reports. It may involve adjusting SPF and DKIM records, addressing issues with legitimate third-party services, or updating the policy based on changing email infrastructure.

How can I configure my domain to use DMARC?

I think by now you’ve come to the conclusion that DMARC is fantastic. To what extent does your domain still need to align with DMARC? This is where things get complicated, and it takes more time than is ideal because of the inherent danger in doing so. Simply publishing a “reject” record may instruct ISPs to block otherwise-legitimate email messages. We can reduce the danger of this undertaking by splitting it into the two phases of “observation” and “implementation.”

Observing DMARC 

  • Start tracking outcomes by making a DMARC record- Monitoring is the initial step in DMARC implementation. You can’t reject emails unless you know their sources. It’s likely that you’re familiar with your email marketing, support, inbox, and drip email services, but are you aware of the servers and administrative tools at your disposal? It’s hard to remember all of these sources. DMARC’s developers realized this and included reporting. Monitoring email traffic for passing or failing messages is the first step to establishing DMARC. Adding a DNS record for DMARC on your domain is the only step needed.
  • Examine DMARC report data for examples of successful, unsuccessful, and absent origins- You are now receiving the reports on a weekly basis and may be using the API to get more in-depth information. Seeing all of the potential email service providers for your domain at once can be a lot to take in. 

The role that DMARC plays in preserving your domain’s good email standing.

The statistics are the first thing that you will see when you open the document. To wit:

  • ISPs report the total number of messages they processed and transmitted.
  • Number of messages where both SPF and DKIM checks passed; also known as “fully aligned.”
  • Not enough SPF or DKIM was present in the quantity of messages.
  • Align DMARC with DKIM and SPF by converting all known email sources- Each week, you receive reports and analyze the data to find reliable sources. Make sure each IP address or domain you send from is signed with DKIM and uploaded to your SPF record. This is laborious, but you can address issues as you find them. Identifying sources is difficult. List each source where you send emails to simplify this. You can match new sources in reports to your list. Email, ecommerce, marketing, and server notifications and alarms are examples. Gmail, Salesforce, Intercom, Mail Campaign Monitor, Mailchimp are examples.DMARC reports can resolve the source IP address. The report’s IP addresses link to “http://whois.domaintools.com,” which displays the IP’s location and owner.
  • Once everything is set up, you may begin blocking email servers that do not follow DMARC’s guidelines.
  • The final goal is to publish a reject record that will cause any email that is not DMARC-compliant to be rejected.


In an era where email-based scams and fraudulent activities are rampant, implementing DMARC is crucial for organizations seeking secure and reliable email communication. DMARC offers a comprehensive solution to combat phishing attempts, protect brand reputation, and improve email deliverability. By combining SPF and DKIM authentication protocols, DMARC provides an additional layer of security and control over incoming email messages. The benefits of DMARC go beyond safeguarding against cyber threats. It also provides valuable reporting and compliance advantages. By understanding and implementing DMARC effectively, organizations can ensure successful email delivery, protect their recipients from malicious attacks, and build trust in their mail campaigns. It’s time to embrace DMARC and take a proactive approach to secure our email ecosystem.

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