How does DMARC impact email deliverability, and what are the pros and cons of using it?
Matthew Whittaker
Co-founder & CTO, Suped
Published 17 Jun 2025
Updated 16 Aug 2025
8 min read
When delving into the complexities of email deliverability, DMARC often emerges as a critical topic. It's an authentication protocol designed to protect your domain from unauthorized use, like spoofing and phishing. Alongside SPF and DKIM, DMARC helps email receivers verify that an incoming email is indeed from the sender it claims to be, playing a crucial role in the broader landscape of email security.
The question of how DMARC impacts email deliverability, and what the true pros and cons of using it are, is a nuanced one. While its primary purpose is security and brand protection, its influence on whether your emails reach the inbox or land in the spam folder is undeniable. Mailbox providers increasingly rely on DMARC, among other signals, to assess sender legitimacy.
My goal is to clarify this relationship, examining how DMARC contributes to, or in some cases complicates, your email deliverability efforts. Understanding these dynamics is essential for any sender looking to optimize their email performance and maintain a strong sender reputation.
DMARC, or Domain-based Message Authentication, Reporting, and Conformance, builds upon existing email authentication methods, SPF and DKIM, by providing a framework for domain owners to specify how receiving email servers should handle emails that fail authentication checks. It also offers a reporting mechanism, allowing domain owners to receive feedback on how their emails are being handled across the internet.
The core of DMARC's operation lies in its policies, which are published as a DNS TXT record. These policies dictate the action to take when an email fails DMARC authentication. The three main policy options are: p=none (monitor only), p=quarantine (send to spam/junk), and p=reject (block delivery). This allows you to gradually enforce policies as you gain confidence in your legitimate sending sources.
A crucial aspect of DMARC is DMARC alignment. This means that the domain in the From header of your email (the one users see) must align with the domain that passed SPF or DKIM checks. Without proper alignment, even if SPF or DKIM passes, DMARC will fail. This concept is fundamental to how DMARC, SPF, and DKIM work together.
While DMARC itself is fundamentally an anti-fraud protocol, it has a significant, indirect impact on email deliverability. When your emails consistently pass DMARC checks, it signals to mailbox providers that you are a legitimate sender, building trust and positively influencing your domain reputation. In turn, a stronger reputation often leads to better inbox placement rates.
Google and Yahoo's new sender requirements for 2024 make DMARC (or at least robust SPF/DKIM with DMARC reporting) a de facto necessity for bulk senders. Failure to implement DMARC, or consistently failing DMARC checks, can directly lead to emails being sent to spam or outright rejected. This is particularly true for domains that are frequently spoofed.
Conversely, a lack of DMARC implementation, especially when your domain is a target for impersonation, can harm your deliverability indirectly. Without DMARC, you lose the ability to instruct receiving servers on how to handle fraudulent emails appearing to come from your domain. This can dilute your sender reputation and lead to legitimate emails being caught in spam filters, even if they pass SPF and DKIM. The reports generated by DMARC also provide crucial insights into authentication failures, which can help in troubleshooting DMARC issues that could impact your deliverability.
DMARC and deliverability
While DMARC is not solely a deliverability protocol, its impact is profound. Proper DMARC configuration and enforcement build trust, a key factor in consistent inbox placement. Ignoring DMARC, particularly for high-volume senders, increasingly puts your emails at risk of rejection or being marked as spam by major mailbox providers.
The pros of implementing DMARC
Implementing DMARC offers several compelling advantages that extend beyond just authentication. Primarily, it significantly enhances your brand's protection against email fraud, such as phishing and spoofing. By telling receiving servers what to do with unauthenticated emails from your domain, you prevent malicious actors from impersonating your brand and potentially harming your customers or reputation.
From a deliverability standpoint, a correctly implemented DMARC policy acts as a strong positive signal. It demonstrates to mailbox providers that you take email security seriously, which can lead to improved sender reputation and better inbox placement. Over time, as more legitimate emails pass DMARC, your domain's trustworthiness grows, making it less likely for your emails to be flagged as suspicious.
One of DMARC's most powerful features is its reporting capability. You receive aggregated reports (RUA) and forensic reports (RUF) that give you unparalleled visibility into your email ecosystem. These reports detail who is sending email on behalf of your domain, which emails are passing or failing authentication, and why. This information is invaluable for identifying unauthorized senders, detecting potential misconfigurations, and optimizing your legitimate email streams.
Finally, DMARC is a prerequisite for implementing BIMI (Brand Indicators for Message Identification). BIMI allows your brand's logo to appear next to your email in supporting inboxes, providing an additional layer of brand recognition and trust for recipients. While BIMI's direct impact on deliverability is still being studied, the added visual branding can certainly contribute to recipient engagement and trust.
Enhanced security
Brand protection: Prevents unauthorized use of your domain for phishing and spoofing attacks.
Fraud prevention: Reduces the likelihood of malicious emails reaching inboxes, protecting your recipients.
Improved insights
Visibility: Provides detailed reports on email authentication status from various receivers.
Troubleshooting: Helps identify and fix legitimate sending sources that are not correctly authenticated.
Compliance: Aligns with evolving email security standards from major providers.
BIMI eligibility: Unlocks the ability to display your brand logo in supporting inboxes.
The cons of implementing DMARC
Despite its many benefits, DMARC implementation is not without its challenges and potential pitfalls. The most significant risk is that legitimate emails might fail DMARC authentication and subsequently be rejected or quarantined, especially when transitioning to an enforcing policy like p=reject. This can happen if you have legitimate sending sources, such as third-party marketing platforms or transactional email services, that are not properly configured to align with your DMARC policy. You can learn more about this by reviewing the DMARC.org's documentation on DMARC usage.
The complexity of DMARC implementation and ongoing management can also be a con. It requires a thorough understanding of all your email sending sources, including internal systems, cloud services, and third-party vendors. Misconfigurations of SPF or DKIM, or a failure to ensure DMARC alignment for all legitimate traffic, can inadvertently lead to deliverability issues. This is why a phased approach, starting with a p=none policy and gradually moving to enforcement, is highly recommended.
Another concern is the potential for a temporary drop in deliverability rates during the transition to an enforcing DMARC policy. Even with careful planning, some legitimate emails might get caught in the filters initially. Continuous monitoring of DMARC reports is essential to quickly identify and resolve any authentication failures or unexpected blockages. Failing to address these issues can negatively impact your sender reputation and lead to your emails being placed on a blocklist or blacklist, affecting deliverability in the long run.
Transitioning to a DMARC enforcement policy
When moving from p=none to p=quarantine or p=reject, proceed with extreme caution. This step can significantly impact deliverability if not all legitimate sending sources are properly authenticated and aligned. Always analyze DMARC reports thoroughly at p=none before increasing enforcement.
Views from the trenches
Best practices
Start with a DMARC policy of p=none to monitor email traffic and gather comprehensive reports without impacting deliverability.
Ensure all legitimate email sending services are correctly configured for SPF and DKIM, and achieve DMARC alignment before moving to stricter policies.
Regularly review your DMARC aggregate reports to identify any new or unauthorized sending sources and address authentication failures promptly.
Gradually increase your DMARC enforcement by moving from p=none to p=quarantine, then to p=reject, once you are confident in your email ecosystem.
Educate your team on DMARC and its importance for email security and deliverability to avoid misconfigurations or unexpected issues.
Common pitfalls
Jumping directly to an enforcing DMARC policy (p=quarantine or p=reject) without first analyzing reports at p=none.
Neglecting to configure DMARC alignment for all legitimate email sending platforms, leading to legitimate emails being quarantined or rejected.
Ignoring DMARC reports, which can hide unauthorized email activity or ongoing authentication issues that impact deliverability.
Failing to account for email forwarding services, which can break SPF and DKIM authentication and lead to DMARC failures.
Assuming DMARC alone guarantees inbox delivery, overlooking other crucial factors like content, recipient engagement, and IP reputation.
Expert tips
Implement DMARC as part of a holistic email authentication strategy, including SPF, DKIM, and even BIMI.
Utilize DMARC reporting tools to simplify the analysis of complex XML reports and gain actionable insights.
Consider setting a DMARC record for all domains, including those not actively sending email, to prevent domain impersonation.
Be aware that DMARC is an authentication standard, not primarily an anti-spam tool, although it contributes to spam reduction.
For large organizations, allocate dedicated resources for DMARC implementation and ongoing monitoring to ensure success.
Marketer view
A marketer from Email Geeks says that if your DMARC failed, there are high chances mailbox providers supporting DMARC will put the emails to junk or reject them, as that is the purpose of DMARC. However, DMARC passing does not guarantee inbox delivery.
2021-11-04 - Email Geeks
Marketer view
A marketer from Email Geeks warns that mailbox providers can certainly reject emails if a p=reject policy is set, and this is a pitfall if you are unaware of all your mail streams when configuring it.
2021-11-04 - Email Geeks
The bottom line on DMARC
DMARC is no longer just a recommendation, especially for high-volume senders. It has become a foundational element of modern email security and deliverability. While it's primarily an anti-fraud mechanism, its role in building and maintaining sender reputation is crucial for ensuring your legitimate emails consistently reach the inbox.
The benefits of DMARC, including enhanced brand protection, improved visibility into email traffic, and a stronger deliverability signal, far outweigh the challenges. However, successful implementation requires careful planning, thorough analysis of reports, and a phased rollout to avoid inadvertently blocking legitimate emails. Continuous monitoring is key to leveraging DMARC effectively.
By understanding both the pros and cons, you can make informed decisions about your DMARC strategy, ensuring your emails are not only secure but also consistently delivered to their intended recipients. It’s an investment that pays off in both security and deliverability dividends.
Google and 
Yahoo's new sender requirements for 2024 make DMARC (or at least robust SPF/DKIM with DMARC reporting) a de facto necessity for bulk senders. Failure to implement DMARC, or consistently failing DMARC checks, can directly lead to emails being sent to spam or outright rejected. This is particularly true for domains that are frequently spoofed.
