Why is a DMARC "quarantine" or "reject" policy not required for SOC2 or ISO certifications?
Matthew Whittaker
Co-founder & CTO, Suped
Published 20 Nov 2025
Updated 20 Nov 2025
6 min read
Email security has become a critical concern for businesses of all sizes, especially with the rise of phishing and spoofing attacks. DMARC (Domain-based Message Authentication, Reporting, and Conformance) is a powerful email authentication protocol designed to protect your domain from unauthorized use. It allows domain owners to tell receiving mail servers what to do with emails that fail authentication, offering policies like 'none' (monitoring), 'quarantine' (send to spam), or 'reject' (block entirely).
Given its strong capabilities in preventing email impersonation, many assume that having an enforcing DMARC policy, specifically p=quarantine or p=reject, would be a mandatory requirement for achieving stringent security certifications like SOC2 or ISO 27001. However, this isn't always the case, leading to confusion for many organizations.
While some governments and specific regulations might push for DMARC enforcement, global security certifications often take a broader, more control-focused approach. I'll explain why a DMARC 'quarantine' or 'reject' policy isn't strictly required for SOC2 or ISO certifications and what this means for your email security strategy.
The evolving landscape of security standards
SOC2 (Service Organization Control 2) and ISO 27001 (Information Security Management Systems) are frameworks that assess and certify an organization's information security practices. They focus on the establishment, implementation, maintenance, and continuous improvement of a company's security posture. Rather than prescribing specific technical controls like a DMARC p=reject policy, these certifications typically require evidence of robust controls that address specific risks, such as unauthorized access, data integrity, and system availability.
The slow pace of auditors and audit processes is often cited as a reason for this gap. While DMARC monitoring and enforcement are widely recognized as best practices for email security, certification bodies focus on whether an organization has appropriate controls in place to mitigate risks, not necessarily the most advanced version of every possible control. They look for evidence that you've identified threats like email spoofing and implemented measures to address them.
For instance, an auditor might be satisfied if an organization demonstrates active DMARC reporting and has a plan to move to a more restrictive policy, even if they're currently at p=none. What auditors are looking for is a comprehensive approach to email authentication, including SPF and DKIM records, and a documented process for addressing authentication failures, rather than a specific DMARC enforcement policy from day one.
Beyond compliance: The real benefits of DMARC enforcement
Although not strictly mandated, moving to a DMARC policy of p=quarantine or p=reject offers significant security benefits that go beyond basic compliance. These policies actively prevent fraudulent emails from reaching your customers' inboxes, protecting your brand reputation and reducing the risk of phishing attacks. Many government entities, like the Canadian Centre for Cyber Security, strongly advocate for these enforcement policies as a best practice for email security. You can refer to their email security best practices document for more details.
A DMARC policy of p=none (monitoring mode) allows you to gather data on email authentication failures without affecting email delivery. While compliant in many audits, it doesn't actively block spoofed emails. It provides visibility but not direct protection against malicious use of your domain.
Enforcement policies like p=quarantine or p=reject actively tell receiving mail servers to treat unauthenticated emails as suspicious or to block them entirely. This provides real-time protection against spoofing and phishing, significantly enhancing your domain's security posture.
Implementing an enforcement policy can also improve your email deliverability. Mailbox providers like Gmail and Yahoo are increasingly scrutinizing sender authentication. A strong DMARC policy signals to these providers that you take email security seriously, which can positively impact your sender reputation and inbox placement.
Furthermore, a DMARC enforcement policy is a strong signal to auditors that you have a proactive approach to mitigating email-borne threats. As noted by 101domain, an auditor will be looking for a DMARC enforcement policy as a control tool to address email spoofing risk. While not a strict ISO/SOC2 requirement, it demonstrably enhances your security posture and simplifies audit responses.
Practical steps for DMARC implementation
Achieving a DMARC enforcement policy requires a careful and phased approach. You should never jump straight to p=reject without thoroughly analyzing your email traffic. The first step is to deploy a DMARC record with a p=none policy to monitor your email streams. This allows you to identify all legitimate sending sources and ensure they are properly authenticated with SPF and DKIM.
Initial setup: Start with a DMARC record using p=none and specify rua tags to receive aggregate reports. These reports provide invaluable insight into your email ecosystem.
Analyze reports: Use a DMARC reporting tool like Suped to easily visualize and understand the authentication status of your email. Our AI-powered recommendations will guide you in fixing issues.
Address failures: Identify legitimate senders failing SPF or DKIM and configure them correctly. This might involve updating SPF records or ensuring DKIM signatures are valid.
Iterate and enforce: Once satisfied that all legitimate emails are authenticating, gradually transition to p=quarantine, then to p=reject. Our real-time alerts help you monitor this process closely.
For organizations managing multiple domains or acting as Managed Service Providers (MSPs), Suped offers an MSP and multi-tenancy dashboard that simplifies DMARC management across all your clients. This centralized view, combined with our SPF flattening capabilities, ensures you can reach enforcement faster and maintain compliance effortlessly. Even if an auditor isn't explicitly looking for p=reject, demonstrating a clear strategy for email security will significantly strengthen your position during any audit.
For many businesses, the journey to a full DMARC enforcement policy can be complex, involving multiple sending services and potential alignment issues. Leveraging a unified platform that brings together DMARC, SPF, and DKIM monitoring with blocklist and deliverability insights can streamline this process. Such tools empower you to make informed decisions about your email authentication policies, ensuring both security and optimal deliverability.
Views from the trenches
Best practices
Actively monitor DMARC aggregate reports from the start, even with a 'p=none' policy, to map all sending sources.
Prioritize fixing SPF and DKIM authentication for legitimate senders before considering enforcement policies.
Use a DMARC monitoring tool with AI-powered recommendations to simplify analysis and actionable steps.
Develop a phased rollout plan for DMARC enforcement, moving from 'p=none' to 'p=quarantine' then 'p=reject'.
Common pitfalls
Expecting auditors to strictly require 'p=quarantine' or 'p=reject' for SOC2/ISO without a clear security control link.
Implementing 'p=reject' too quickly, causing legitimate emails to be blocked or quarantined by receiving servers.
Neglecting to analyze DMARC reports, thus missing unauthorized sending sources or authentication failures.
Underestimating the complexity of DMARC implementation, especially with numerous third-party email services.
Expert tips
The key for auditors is demonstrating a clear, documented process for managing email security risks, not just a policy.
Some governments are mandating DMARC enforcement, which might influence future global certification standards.
Consider DMARC as a critical component of your overall email security strategy, not just a compliance checkbox.
Educating leadership and legal teams about DMARC's importance can help drive adoption of stronger policies.
Expert view
Expert from Email Geeks says auditors and audit processes often move slowly, which explains why DMARC enforcement isn't a hard requirement.
2024-11-12 - Email Geeks
Marketer view
Marketer from Email Geeks says a consultancy helping with ISO renewal never looked at DMARC during the audit, highlighting the variability.
2024-11-12 - Email Geeks
The path to a stronger DMARC policy
While a DMARC quarantine or reject policy might not be explicitly mandated for SOC2 or ISO certifications, its value in enhancing email security and protecting your brand cannot be overstated. These certifications focus on the existence and effectiveness of security controls, and a well-implemented DMARC enforcement policy is a robust control against email spoofing.
Organizations should view DMARC enforcement as a crucial part of their overall security strategy, rather than just a compliance checkbox. By systematically moving towards a stricter policy, you not only improve your security posture but also demonstrate due diligence to auditors and stakeholders. Tools like Suped simplify this journey by providing the insights and guidance needed to navigate DMARC complexities, making it accessible to any organization aiming for top-tier email security.
Whether you're an SMB, a large enterprise, or an MSP, strengthening your DMARC policy is a proactive step that will yield significant returns in trust, security, and deliverability. Start with monitoring and gradually move towards enforcement to secure your email ecosystem effectively.
Gmail and Yahoo are increasingly scrutinizing sender authentication. A strong DMARC policy signals to these providers that you take email security seriously, which can positively impact your sender reputation and inbox placement.
