DMARC and DKIM are email authentication protocols that help organizations combat impersonation attacks and email compromise. DMARC and DKIM are important tools for protecting your brand, maintaining email deliverability, and reducing email-borne threats. However, they do not replace each other. DMARC and DKIM serve different purposes when it comes to authenticating your emails, and work best when used together for comprehensive security.

Key Takeaways

DMARC and DKIM are essential email authentication protocols that serve distinct functions in protecting against impersonation attacks.
DMARC defines policies for handling authentication failures while DKIM authenticates email content to prevent tampering.
Utilizing both DMARC and DKIM together enhances email security significantly compared to using them in isolation.
The integration of DMARC, DKIM, and SPF provides a robust defense mechanism against email-borne threats, ensuring better deliverability and brand protection.
Implementing these protocols can yield improved monitoring and compliance for organizations, reducing unauthorized usage of their domains.

DMARC Vs DKIM: Key Differences

	DMARC	DKIM
Purpose	DMARC defines policies for handling emails that fail authentication checks.	DKIM signs outgoing messages with a digital cryptographic signature to preserve message integrity.
Dependency	DMARC needs either SPF or DKIM implementation to function	DKIM can function independently, but further enhances security when combined with DMARC.
Policy Enforcement	DMARC policy can be set to “reject” or “quarantine” to allow rejection and quarantining of fraudulent emails.	DKIM does not provide any policy enforcement benefits within its functioning.
Reporting	DMARC offers reporting abilities in the form of Aggregate and Forensic DMARC reports.	DKIM does not offer any reporting capabilities of its own, but DKIM authentication information is displayed in DMARC reports.

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Understanding DMARC and DKIM

DMARC: What Is It and How Does It Work?

DMARC is an acronym for Domain-based Message Authentication Reporting and Conformance. DMARC tells email servers what to do with emails that fail SPF or DKIM checks: deliver, quarantine, or reject them.

The basic function of DMARC is to determine whether or not an email should be delivered to its intended recipient. In order to do this, it determines what kind of DNS records are stored for a particular domain. The DMARC record itself contains instructions as to where the email should be sent if it fails either SPF or DKIM checks.

It also provides instructions as to how much of the message should be delivered if it fails authentication. There are three possible DMARC policy options here:

‘none’ means that all failed messages should be treated as normal
‘quarantine’ means that some portion of the message should be delivered, but only with a warning
‘reject’ means that no part of the message should be delivered at all

Through this process, DMARC plays a critical role in preventing direct-domain spoofing and phishing attacks and improving overall email deliverability.

DKIM: What Is It and How Does It Work?

DKIM is an acronym for DomainKeys Identified Mail. It is a method of verifying the authenticity of emails using cryptographic authentication.

DKIM adds a digital signature to your emails, allowing recipients to verify that the message wasn’t tampered with during transit.” This signature is added by affixing a header to the email that contains a few key pieces of information. They include:

The domain name used to send the email.
A DKIM selector is used to help locate the DKIM public keys in the DNS in case there are multiple DKIM records published.
The public key will be used by the recipient’s mail server to decrypt part of the message and compare it against another part of the message in order to verify that it was sent from an authorized server.
A hash value is generated from parts of the message so that those parts can be verified by anyone who has authorized access.

DKIM alone cannot prevent spoofing and phishing attacks but can play a critical role in safeguarding against email tampering and Man-in-the-middle attacks.

Does DMARC Require DKIM?

DMARC does not require DKIM but works best when combined with it. You can configure DMARC with SPF alone, but using both SPF and DKIM provides stronger security. Let’s find out how:

Configuring DMARC paired with SPF

You can skip setting up DKIM for your domain and still configure DMARC by pairing it up with SPF. This is because for your emails to pass DMARC, either SPF or DKIM identifier alignment is required. To implement DMARC without DKIM:

Make a list of all your authorized sending sources
Create an SPF record using our free SPF record generator and include all your sending sources to authorize them
Paste the record on your DNS
Create a DMARC TXT record for your domain using our free DMARC record generator
Copy and paste this record on your DNS to activate DMARC

Configuring DKIM on its own

If you want to skip the DMARC configuration, you can choose to implement DKIM on its own. To do so head over to the PowerDMARC DKIM record generator tool and enter the following information:

A unique DKIM selector key (it can be a 1024 or 2048 bits long alphanumeric value)
Your domain name (without any prefixes, for example, if your website URL is https://www.domainname.com, your domain name will be domainname.com)

Once you hit the generate record button our AI generates your DKIM TXT record along with instructions on how to publish it on your DNS to activate the protocol.

How Do DMARC and DKIM Work Together?

DMARC and DKIM together form a powerful combination of email authentication systems to safeguard your domain. The two protocols when implemented together perform the following process:

Your outgoing email is signed with a DKIM signature using the DKIM private key.
On reaching the recipient mail server, the server looks up the DKIM public key to match it with the private key.
If a match is made, the mail is delivered.
If a match isn’t found, depending on the sender’s DMARC policy the mail is either quarantined or rejected altogether.

Image here showing the flow

Benefits of Combining DMARC and DKIM

There are several benefits of combining the two protocols, including:

Stronger email authentication
Improved protection against phishing and spoofing attacks
Improved brand and domain reputation
Increased email deliverability rates
Better control over your domain and emails
Reduced bounces and email spam rates

By deploying DMARC and DKIM, organizations gain greater control over their email domains, reducing unauthorized use. For instance, after implementing these protocols, CloudIntellect was able to detect and respond to email-borne threats proactively, enhancing their clients’ email security posture.

DMARC Vs DKIM: Which Should You Use?

Both DMARC and DKIM play crucial roles in email authentication, that are distinctive and specific to each protocol. Let’s explore what you should use and when:

When to Use DKIM

If preventing email tampering is your primary concern
When you wish to reduce spam
If you use multiple third-party email vendors
When you want to verify email integrity without enforcing strict policies.
When you send less than 5000 emails per day

When to Use DMARC

When preventing phishing and spoofing attacks is your primary lookout
When you wish to improve email deliverability and brand reputation
When you wish you monitor your email traffic and authentication results
When you send more than 5000 emails per day
When your company handles or processes payment card data
When you want to enforce your email authentication

The best practice is to combine DKIM and DMARC instead of choosing one over the other. This will provide comprehensive security against email-based cyber attacks. It will also help with monitoring and visibility into your email channels.

Benefits of Combining DMARC, DKIM and SPF

We at PowerDMARC believe that having a multi-factor approach to email authentication can be a game-changer. It can significantly improve domain and information security. This is why we recommend organizations implement DMARC, DKIM, and SPF together for well-rounded email protection.

Aligning your emails against both SPF and DKIM authentication standards while using DMARC for special instructions and reverse feedback can help you gain 100% compliance on your emails. It also helps build trust and create a solid foundation for your organization’s domain. This system ultimately ensures and improves deliverability.

The PowerDMARC email authentication suite gives you an automated experience while configuring your protocols. Our DMARC services come paired with SPF and DKIM to take your email’s security to the next level. Sign up for our free DMARC today to try out the benefits yourself!

FAQs

1. Which is better for email authentication: DMARC or DKIM?

There is no one over the other as DMARC allows enforcement and reporting while DKIM upholds message integrity. Both work best together.

2. What happens if an email fails DMARC but passes DKIM?

If SPF fails and DKIM passes, DMARC may still fail depending on the sending domain’s alignment settings and DMARC policy.

3. Do email providers require both DMARC and DKIM?

While DMARC requires either SPF or DKIM enabled to function, some email providers require both DMARC and DKIM.

4. What is the impact of DMARC and DKIM on email marketing campaigns?

The implementation of DMARC and DKIM can boost email marketing campaigns by improving email deliverability rates and reducing spam.

5. Can I implement DMARC and DKIM without technical expertise?

Both protocols can easily be implemented without technical expertise using Hosted DMARC and Hosted DKIM solutions online.

6. Can I use DMARC and DKIM for multiple domains?

Yes, each domain can have its own unique DKIM and DMARC records. However, it is best to avoid multiple DMARC records for a single domain.

About
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Yunes Tarada

Domain & Email Security Expert at PowerDMARC

Yunes is an Operations Team Lead at PowerDMARC with expert knowledge in email authentication and security. Yunes is a Microsoft-certified Azure Administrator Associate with certifications in CompTIA A+ and many more.

DMARC vs DKIM: Key Differences & How They Work Together