What Is DMARC ? | Why DMARC Is Important ? | Understanding DMARC Records

​Email is one of the preferred official ways to communicate when it comes to reliable communication. The major reasons for this are that communications made from an email domain are from an organization to whom the receiver is known. Also, the email domain reputation is somewhat connected to the organization's email domain. But what happens if the email domain is spoofable? This would not only break the reliability of the email domain, but would also affect the email domain's reputation.

DMARC stands for Domain-based Message Authentication, Reporting, and Conformance. It is a mechanism that expresses domain-level policies and a preference for message validation from a specific email domain. DMARC increases and improves email handling, which SEGs cannot do on their own. Although DMARC can be used to combat exact email domain spoofing problems and is useful in the creation of reliable defensible message streams.

DMARC is designed to prevent bad or unauthorized actors from sending emails that claim to be from the legitimate sender. One of the primary examples of this is phishing, which is where a bad actor claims and pretends to be a genuine sender. The good news is that DMARC is implemented at a large scale and Internet-wide as one of the primary anti-phishing measures.

DMARC implementation is very important, as:

  • It protects your brand reputation
  • It increases visibility from DMARC reports
  • It enables policy for dealing with messages which fail to authenticate.

DMARC depends on the results of SPF and or DKIM, so at least one has to be in place for the email domain. The DMARC journey starts from p=none to p=reject. (p is the policy in the DMARC syntax that we will learn about in the next paragraphs.)

Understanding a basic DMARC Syntax

v=DMARC1; p=quarantine; pct=100; rua=mailto:dmarcrua@xyzyourdomain.com
  • v=DMARC1 represents the protocol version.
  • p=quarantine represents the current policy where p= can be none or reject too.
  • pct=100 represents the percentage subjected to filtering.
  • rua = the address to set for sending the aggregate report.

​DMARC plays an essential role in not just authenticating but also in ownership of an email domain. DMARC preserves the positive aspects of the current email infrastructure. DMARC allows email domain owners to assert the preferred handling of authentication failures. It also works at an Internet scale. DMARC also allows domain owners to authenticate deployment.

DMARC enables users to be reliable, communicate policies, and is also able to be put into internet-wide action. It also permits identifier alignment. Additionally, DMARC enables strict handling of messages that fail authentication checks, from no action to message rejection. DMARC policies are published by the domain owners and retrieved by the Mail receiver during the SMTP session via the DNS.


In this article, we learned about the importance of DMARC and its basic syntax. An important point from the checklist is to ensure that an email domain should be protected, and to gain ownership of it. If you liked this article, feel free to share it with your friends and family. Let me know your favourite cybersecurity topic for my next article series on CyberSecurity.