Understanding the Impact of “None” DMARC Policy on Server Behavior

We have set up a DMARC (Domain-based Message Authentication, Reporting, and Conformance) policy of “none” on our domains. This means that the behavior by receiving servers will not be changed. With this policy in place, email receivers will continue to handle incoming messages as they normally would without any additional actions or modifications. In other words, having a DMARC policy of “none” ensures that the existing delivery process remains unaffected and emails are processed according to standard procedures.

What is DMARC?

  • DMARC stands for Domain-based Message Authentication, Reporting, and Conformance.
  • It is an email authentication protocol that helps protect against email spoofing and phishing attacks.
  • With DMARC, domain owners can specify how receiving mail servers should handle emails claiming to be from their domains.

How does DMARC work?

  1. Authentication: When an email is sent using a domain protected by DMARC, the receiving server checks if it passes authentication tests like SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail).
  2. Policy: The domain owner sets up a DMARC policy to instruct receiving servers on how they should treat failed authentication results.
    • “none” policy: This means that no action will be taken when an email fails authentication. Receiving servers will not change the behavior based on the failed result.
    • Other policies: The domain owner can choose to quarantine or reject emails that fail authentication.

Benefits of using DMARC

  • Prevention of Email Spoofing: By implementing DMARC, organizations reduce the risk of their domains being used in phishing attacks or spam campaigns.
  • Improved Deliverability: Properly configured DMARC policies help improve email deliverability as authenticated messages are less likely to be flagged as suspicious or spam by receivers.
  • Actionable Insights: The reporting feature of DMARC provides valuable feedback on who is sending emails on behalf of your domain and whether those senders are authorized.

In conclusion, adopting a strong security measure like setting up a “none” policy with DMARC helps protect your brand’s reputation by mitigating potential risks associated with unauthorized use of your domain in fraudulent activities.

Understanding the ‘none’ policy

The DMARC (Domain-based Message Authentication, Reporting, and Conformance) policy of “none” is a setting that can be implemented on domains to indicate that no action should be taken by receiving servers based on DMARC alignment results. Here’s what you need to know about the ‘none’ policy:

  1. No changes in behavior: When a domain has the ‘none’ policy set up, it means that receiving mail servers will not alter their behavior based on DMARC alignment results. This allows organizations to gain visibility into email authentication issues without impacting email delivery.

  2. Monitoring and reporting: With the ‘none’ policy, organizations can still receive detailed reports from participating receivers about emails sent using their domain. These reports provide valuable insights into potential unauthorized use of their domain or any configuration issues.

  3. Visibility into email authentication: By implementing the ‘none’ policy, organizations can monitor and analyze DMARC data to gain better visibility into how their domain is being used for sending emails. This helps in identifying legitimate sources as well as detecting spoofed or fraudulent emails.

  4. Policy evaluation process: When an incoming email arrives at a receiver with the organization’s domain configured with a ‘none’ policy, several checks are performed:

    • SPF (Sender Policy Framework): The receiver checks if the IP address of the source server matches those authorized by SPF records published for the sender’s domain.

    • DKIM (DomainKeys Identified Mail): The cryptographic signature attached to the message header is verified against DNS records published by the sender’s domain.

    • Alignment check: The alignment between RFC5322.From field (visible address) and either SPF or DKIM is evaluated.

  5. No impact on delivery: As mentioned earlier, when using a ‘none’ policy there won’t be any change in how incoming messages are treated based on authentication results alone. This means that even if an email fails SPF or DKIM checks, it will still be delivered to the recipient’s inbox.

Implementing the ‘none’ policy allows organizations to gain valuable insights into their email authentication landscape while avoiding any disruption in email delivery. It enables them to understand how their domain is being used and take necessary actions to enhance security and protect against spoofed emails.

Implications of not changing behavior by receiving servers

When a DMARC policy of “none” is set up on your domains, it means that the behavior of receiving servers will not be changed. While this may offer some convenience and flexibility, there are several implications to consider:

  1. Reduced protection against unauthorized use: By allowing emails to pass through without any modifications or strict checks, you increase the risk of unauthorized individuals using your domain for phishing attacks or other malicious activities. This can damage your brand reputation and cause harm to both your company and recipients.

  2. Lack of visibility into email abuse: Without enforcing stricter checks on incoming emails, you lose the ability to identify potential sources of abuse or fraudulent activity originating from your domain. This makes it harder for you to take appropriate action and protect yourself against cyber threats.

  3. Inability to prioritize legitimate emails: Receiving servers with no changes in behavior won’t differentiate between legitimate emails sent from authorized sources and those attempting spoofing or impersonation. As a result, important correspondence may get lost among spam messages or end up in recipients’ junk folders.

  4. Limited control over email delivery: When receiving servers don’t modify their behavior based on DMARC policies, you have less control over how your emails are handled by various email service providers (ESPs). This can lead to inconsistent deliverability rates across different platforms and impact the effectiveness of your communication efforts.

  5. Missed opportunity for data analysis: By not implementing stricter DMARC policies that alter server behavior, you miss out on valuable data insights related to email delivery statistics, bounce rates, SPF/DKIM failures, etc., which could help optimize future campaigns and improve overall email performance.

It’s crucial for organizations to carefully evaluate these implications before deciding whether maintaining a DMARC policy of “none” aligns with their security needs and long-term goals.


In conclusion, setting up a DMARC policy of “none” on our domains means that the behavior of receiving servers will not be changed. This provides us with greater control and visibility over email delivery processes while maintaining compatibility with existing systems.

By implementing a DMARC policy of “none,” we are essentially in monitoring mode, allowing us to receive detailed reports about any potential unauthorized use of our domains for sending emails. This enables us to assess the effectiveness of our current email security measures and identify areas that may require further attention.

Furthermore, having a DMARC policy in place helps to establish trust among recipients and reduces the risk of phishing attacks. It allows legitimate emails from our domains to pass through seamlessly without being flagged as spam or rejected by receiving servers.

Overall, adopting a DMARC policy of “none” is a proactive step towards enhancing email deliverability, protecting brand reputation, and ensuring secure communication channels. By closely monitoring email activity and making necessary adjustments based on received reports, we can maintain control over our domain’s integrity while providing better user experiences for both senders and recipients alike.

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