DMARC (Domain-based Message Authentication, Reporting & Conformance) is a powerful tool for email security. But when configuring DMARC, a crucial concept emerges: alignment.

Understanding DMARC Alignment

DMARC alignment refers to the aligning or matching of domains under various sections of senders’ email headers. It ensures that the domains specified in SPF & DKIM authentication mechanisms match the email domain claimed in the “From” address of the email. Simply put, it verifies that the sender’s identity is consistent across different parts of the email.

DMARC achieves this by checking three key areas during email validation:

From Header: This is the email address displayed in the “From” field that recipients see.

Return Path Address (Mail From Domain): This is the domain used for SPF authentication, often found in the “Return-Path” header (also known as the bounce address).

DKIM Signing Domain: This is the domain associated with the DKIM signature used to digitally sign the email content.

If these domains don’t align with the “From” address domain, DMARC authentication fails and DMARC policies come into play. These policies instruct email receivers on how to handle non-aligned messages, such as marking them as spam or rejecting them altogether.  There are three DMARC policies that you can choose from for your email domains and subdomains: none, quarantine, and reject.

Factors Affecting SPF and DKIM Alignment

Several factors can impact alignment:

Third-party Email Clients and Service Providers: These can introduce complications and lead to misalignment.

Forwarded Messages: Forwarded emails may fail alignment due to changes in routing.

DMARC Alignment Modes

DMARC offers two alignment modes, each with its own advantages and considerations:

1. DMARC Relaxed Alignment (Default)

In relaxed alignment, the domain in the “From” address does not need to match the domain in the SPF and DKIM checks exactly. Instead, it only needs to share the same organizational domain. For example:

If the “From” address is user@example.com

The domain in the SPF check could be mail.example.com

The domain in the DKIM check could be example.com

In this case, as long as all these domains share the same organizational domain (example.com), the email will pass the relaxed alignment check..

2. DMARC Strict Alignment

In strict alignment, the domain in the “From” address must exactly match the domain used in the SPF and DKIM checks. For example:

If the “From” address is user@example.com

The domain in the SPF check must be example.com

The domain in the DKIM check must be example.com

If there are any discrepancies, such as a different subdomain being used, the email will fail the strict alignment check.

How to Configure DMARC Alignment Modes

When setting up your DMARC policy, you can specify the alignment mode for both SPF and DKIM. This is done using the adkim (for DKIM) and aspf (for SPF) tags in your DMARC DNS record. Here’s an example of how to set these tags:

Relaxed Alignment:

v=DMARC1; p=none; adkim=r; aspf=r; rua=mailto:dmarc-reports@example.com

In this example, both DKIM and SPF are set to relaxed alignment (r).

Strict Alignment:

v=DMARC1; p=none; adkim=s; aspf=s; rua=mailto:dmarc-reports@example.com

In this example, both DKIM and SPF are set to strict alignment (s).

If you do not specify the adkim and aspf tags in your DMARC policy, the default alignment mode is relaxed for both DKIM and SPF. This means that, by default, DMARC checks will pass as long as the domains share the same organizational domain

Why Relaxed Alignment is Our Recommendation (for Most)

While strict alignment offers the highest security, it can be overly restrictive, especially for organizations with:

• Multiple Email Systems/Services: Many companies use various email platforms or third-party services (e.g., marketing automation) that send emails on their behalf. These services might use subdomains that wouldn’t strictly align with the main domain. Relaxed alignment ensures legitimate emails from these subdomains aren’t flagged.

Benefits of Relaxed Alignment

• Reduced False Positives: Strict alignment can lead to legitimate emails being quarantined or rejected, causing frustration and disruption. Relaxed alignment minimizes this risk.
• Smoother Implementation: Relaxed mode allows for a more gradual DMARC deployment. 
• Flexibility for Growth: As your email ecosystem evolves, relaxed alignment adapts. New subdomains or services can be integrated without worrying about strict alignment roadblocks.
• Manage Email Traffic Independently: You can continue to manage email traffic from the subdomain independently without worrying about strict alignment causing rejections. 
• Prevent Exceeded SPF Lookup Limit: Relaxed mode allows you to avoid exceeding the SPF lookup limit of the parent domain by using a subdomain for the return path. 
• Handle Bounce Emails without Impacting Primary Domain: You can maintain a separate bounce address for the subdomain without affecting the primary domain’s reputation.

Remember, Relaxed Doesn’t Mean Unprotected

While relaxed offers advantages, it’s crucial to monitor your DMARC reports. ProDMARC, for instance, provides detailed insights to help you identify potential spoofing attempts even with relaxed alignment. By analyzing “From” addresses that don’t strictly align, you can take informed actions to further fortify your defenses.

Choosing the Right Alignment Mode

Ultimately, the decision depends on your specific needs and risk tolerance. Here’s a quick guide:

• Choose Strict Alignment if:
  • You have a simple email infrastructure with a single domain and limited subdomains.
• Choose Relaxed Alignment if:
  • You have a complex email setup with multiple domains, subdomains, or third-party services.
  • You want a smoother DMARC deployment and minimize false positives.

ProDMARC: Your Partner in DMARC Success

Regardless of your chosen alignment mode, ProDMARC empowers you with the insights and guidance you need to optimize your DMARC implementation. Our comprehensive DMARC reporting and analytics help you:

• Gain deep visibility into email authentication failures.
• Identify potential spoofing attempts, even with relaxed alignment.
• Track DMARC deployment progress and make informed adjustments.

Ready to take control of your email security?

Schedule a free demo with ProDMARC today and see how our powerful DMARC tool can help you achieve peace of mind! Contact us at +91-9820116312 to know more!