What is DMARC, and why do you need it

Phishing scams and spoofing have become increasingly common during the past few years. Hackers are on a constant lookout for vulnerable domains, and their defense mechanisms can easily be penetrated.

They can then try to impersonate the domain owner’s brand and send emails through what seems to be its domain address. This may lead to spoofing, phishing attacks, spam and fraudulent activities like malware spread, data breach, black market sales, identity thefts, etc. If no action is taken to prevent this, the organization loses its credibility and reputation and even faces financial retributions.

It is thus important to have strong email security and verification program in place. DMARC is an email authenticating protocol that enables an organization to protect its domain from hackers and scams.

How DMARC works

Now let’s look at how DMARC works.

When you publish DMARC for your domain, you can control what happens if a particular message fails the verification test. It means that the recipient’s email server cannot authenticate if the sender of that email is who they say they are.

Messages that are sent to be what appears from the sender’s domain are subjected to a series of authentication checks (in most instances by SPF and DKIM) and are analyzed by the receiving body to determine whether they have actually been sent from the domain in the message.

DMARC is thus responsible for handling the aspect of how the email is to be treated if it fails the authentication tests. Sometimes while other authentication protocols, including SPF ((Sender Policy Framework) or DKIM (Domain keys Identified Mail), pass the email, DMARC may fail it based on its records. This is termed DMARC alignment.

DMARC records are published on the DNS (Domain Name Systems) and provide information on how the email sent from the domain must be handled. As DMARC policy uses DNS to publish the instructions or policy, all email services can decipher how the email from the domain is supposed to be managed.

Should a message fail the authentication test, the recipient’s server determines what to do with it based on the instructions sent by the DMARC records. The email may be sent as it is or, with a warning, or it is quarantined and sent to the spam folder, where it is evaluated manually. Alternatively, it may be rejected altogether.

In short, DMARC acts like a security guard to the email inboxes. If it is implemented properly, an organization can effectively prevent malware attacks, phishing scams and misleading emails from being sent to the inboxes of its employees, customers or clients.