What are the main rules any DMARC must have to accomplish new Gmail and Yahoo requirements?
Michael Ko
Co-founder & CEO, Suped
Published 14 Jun 2025
Updated 17 Aug 2025
9 min read
The email landscape is constantly evolving, and recent updates from major mailbox providers like Gmail and Yahoo have brought DMARC into sharp focus, especially for bulk senders. These new requirements aim to improve email security, combat spam, and protect users from phishing and spoofing attempts. As a sender, understanding these rules is critical for ensuring your emails reach the inbox.
Many people view DMARC as just another DNS record to add, but its impact on your email deliverability can be profound if not implemented correctly. A simple copy-paste approach can lead to significant issues, including your legitimate emails being blocked or sent straight to the spam folder. It is not something to be taken lightly.
The core purpose of DMARC is to tell receiving mail servers what to do with emails that claim to be from your domain but fail SPF or DKIM authentication checks. This protocol acts as a crucial layer of defense, giving you control over unauthorized use of your domain and boosting recipient trust.
In this guide, I will walk you through the essential DMARC rules required to comply with the latest Gmail and Yahoo requirements, and how to strengthen your DMARC policy for robust email security and optimal inbox placement.
DMARC builds upon two foundational email authentication protocols, SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail). For DMARC to pass, an email must authenticate via either SPF or DKIM (or both), and crucially, the domain used in the authentication check must align with the 'From' header domain that your recipients see. This alignment is key.
The new guidelines from Gmail and Yahoo specifically require bulk senders, defined as those sending over 5,000 emails per day to their users, to have a valid DMARC record published in their DNS. While not strictly mandatory for senders below this threshold, implementing DMARC is considered a best practice for all senders looking to maintain good deliverability and protect their brand.
The presence of a DMARC record signals to mailbox providers that you care about email security and are actively working to prevent unauthorized use of your domain. Without it, even emails that pass SPF and DKIM might face increased scrutiny or be more likely to land in spam folders, especially with these new, stricter enforcement policies.
I often see confusion about how DMARC works with SPF and DKIM, particularly regarding alignment. Even if your emails pass SPF or DKIM, if the domain in the From header doesn't align with the authenticated domain, DMARC will fail. This alignment is fundamental to DMARC's effectiveness in preventing spoofing.
For initial compliance with the new Gmail and Yahoo requirements, the absolute safest bare minimum DMARC policy is p=none. This policy tells receiving mail servers not to take any action on emails that fail DMARC, but it still allows you to receive DMARC aggregate reports. These reports are crucial for understanding your email ecosystem.
While p=none might seem counterintuitive for security, it is the recommended starting point for a reason. Deploying a stricter policy like p=quarantine or p=reject without proper understanding and analysis of your email flows can inadvertently cause your legitimate emails to be quarantined or rejected. This is why thorough preparation is essential.
Beyond the policy, including an rua tag pointing to a legitimate report handler is also a crucial requirement. This tag specifies an email address where aggregate DMARC reports should be sent. These reports provide invaluable insights into who is sending email on behalf of your domain, including both legitimate and fraudulent senders, and how well your emails are authenticating.
Monitoring these aggregate reports is the only way to gain visibility into your email ecosystem. It allows you to identify any legitimate sending sources that might not be correctly authenticated and to detect any unauthorized parties attempting to spoof your domain. Without this visibility, moving to a stronger policy is a risky move that can harm your deliverability.
Importance of starting with p=none
Beginning your DMARC journey with a policy of p=none is a critical best practice. This policy allows you to gather DMARC reports and understand your email sending landscape without impacting deliverability. It's a monitoring phase where you collect data on both legitimate and unauthorized email streams.
Before you even consider moving to a stricter policy like p=quarantine or p=reject, you must be certain that all your legitimate email sources are correctly authenticated via SPF and DKIM, and are aligning with your DMARC record. This is a common pitfall that can lead to severe deliverability issues if overlooked.
Beyond the basics: strengthening your DMARC policy
Once you have successfully deployed p=none and are consistently receiving and analyzing DMARC reports, you can consider moving to a more restrictive policy. This is the path to achieving a truly stronger DMARC posture, beyond just meeting the basic compliance for Gmail and Yahoo.
A p=quarantine policy instructs receiving mail servers to place emails that fail DMARC into the recipient's spam or junk folder. This is a good intermediate step, as it provides protection against spoofing while still allowing you to monitor for any unintended impact on your legitimate emails before they are completely rejected.
The strongest policy, p=reject, tells receiving servers to outright refuse emails that fail DMARC. This offers the highest level of protection against domain spoofing but should only be implemented when you are absolutely confident that all your legitimate email streams are correctly authenticated and aligned. Many organizations never reach p=reject due to the complexities of modern email environments.
Before strengthening DMARC policy
No data: Operating without insights into your email sending sources.
Risk of disruption: Legitimate emails may be blocked or sent to spam.
Limited protection: Your domain remains vulnerable to spoofing.
Process
Guesswork: Changes are made without empirical evidence.
Manual checks: Time-consuming and prone to errors.
After strengthening DMARC policy
Data-driven decisions: Utilizing DMARC reports for informed policy adjustments.
Improved deliverability: Higher inbox placement rates for legitimate emails.
Enhanced brand trust: Robust protection against spoofing and phishing.
Process
Phased rollout: Gradually moving from p=none to p=quarantine or p=reject.
Automated reporting: Efficiently collecting and analyzing DMARC data.
The transition to a stronger DMARC policy requires careful planning and continuous monitoring of your DMARC reports. It is not a one-time setup, but rather an ongoing process of refinement and adjustment to ensure that only authorized emails are delivered successfully. I recommend a phased approach, starting with p=none, then moving to p=quarantine, and only then considering p=reject when you are confident in your authentication coverage.
Key DMARC record components
A DMARC record is a TXT record added to your domain's DNS. It consists of various tags that define the policy and reporting preferences. While the basic v=DMARC1; p=none; is the minimum, understanding other key tags allows for a more comprehensive and robust policy.
Some of the most important tags include pct, which allows you to apply the policy to only a percentage of your emails, and fo, which specifies how forensic (failure) reports should be generated. Forensic reports (ruf) can provide detailed information about authentication failures, but they can also be voluminous and contain sensitive information.
It is important to remember that DMARC is not a set-and-forget solution. It requires ongoing monitoring and adjustments to ensure continued compliance and optimal deliverability. Regularly reviewing your DMARC reports and making necessary changes to your SPF and DKIM records will help you maintain a strong email sending reputation and avoid being caught by blocklists (or blacklists).
For a detailed breakdown of all available DMARC tags and their uses, consult the list of DMARC tags and their meanings. Proper configuration and ongoing management are vital for compliance and security.
Tag
Description
Example Value
v
DMARC protocol version
DMARC1
p
Policy for failed emails
none, quarantine, reject
rua
Aggregate report URI
mailto:reports@example.com
ruf
Forensic report URI
mailto:forensics@example.com
fo
Forensic reporting options
0, 1, D, S
pct
Percentage of emails to which policy applies
0-100
Views from the trenches
Best practices
Start with a `p=none` DMARC policy to monitor your email streams without impacting deliverability.
Always include an `rua` tag in your DMARC record to receive aggregate reports and gain visibility.
Ensure all legitimate sending sources are properly authenticated with SPF and DKIM and align correctly.
Regularly review DMARC aggregate reports to identify unauthorized sending and authentication gaps.
Gradually transition to stricter policies (`p=quarantine`, then `p=reject`) only after validating your email ecosystem.
Common pitfalls
Deploying a `p=quarantine` or `p=reject` policy without first analyzing DMARC reports.
Forgetting to include the `rua` tag, leaving you blind to your email authentication performance.
Not ensuring DMARC alignment for all legitimate sending sources, leading to deliverability issues.
Treating DMARC as a one-time setup rather than an ongoing monitoring and adjustment process.
Not addressing SPF or DKIM failures reported in DMARC, which undermines the policy's effectiveness.
Expert tips
Understand that DMARC can negatively impact deliverability if not properly configured and monitored.
If your 'From' domain sends email from multiple places, confirm all are authenticated correctly before a stronger policy.
A stronger DMARC policy is feasible for single-source domains, but only after report analysis.
Don't solely rely on cutting and pasting DMARC records, fully grasp its implications.
Actively analyze DMARC reports to confirm the impact of any policy changes on your mail flow.
Expert view
An expert from Email Geeks says DMARC's fundamental purpose must be understood to prevent email deliverability issues upon deployment.
Feb 7, 2024 - Email Geeks
Expert view
An expert from Email Geeks says DMARC is more than a simple DNS record, and its misconfiguration can lead to significant deliverability problems.
Feb 7, 2024 - Email Geeks
Ensuring DMARC success and robust security
The new DMARC requirements from Gmail and Yahoo are a clear signal that email authentication is no longer optional, especially for bulk senders. Implementing DMARC with at least a p=none policy and an rua tag is your entry ticket to maintaining deliverability to these major mailbox providers.
However, stopping at the minimum is a missed opportunity for enhanced email security and brand protection. By embracing a data-driven approach, utilizing DMARC reports, and incrementally moving towards stricter policies like p=quarantine or p=reject, you can significantly reduce the risk of spoofing and phishing attacks while building a stronger sender reputation.
Remember, proactive management and a deep understanding of how DMARC interacts with your entire email infrastructure are key to long-term success. This is not just about compliance, it is about securing your email communication and ensuring your messages consistently reach their intended audience, avoiding the spam folder or potential blacklist (or blocklist) listings.
Investing time and resources into proper DMARC implementation and monitoring will pay dividends in improved deliverability and protection against email-based threats, safeguarding your brand's reputation and trust with your recipients.
Gmail and 
Yahoo.
