Are there GDPR concerns related to IP addresses in DMARC reporting?
Michael Ko
Co-founder & CEO, Suped
Published 4 Jun 2025
Updated 19 Aug 2025
7 min read
When I talk to clients about DMARC, a common concern that arises, especially for those operating in Europe or dealing with European customers, is how DMARC reporting aligns with the General Data Protection Regulation (GDPR). The core of this concern often revolves around the IP addresses contained within DMARC reports. It's a valid question, as IP addresses can indeed be classified as personal data under certain circumstances.
DMARC (Domain-based Message Authentication, Reporting & Conformance) is a crucial email authentication protocol that helps protect your domain from impersonation and phishing. A key benefit of DMARC is its reporting mechanism, which provides insights into email authentication results across the internet. These reports help you understand how your domain's emails are being handled by various mail servers and identify any unauthorized use.
However, with great data comes great responsibility. The question isn't whether DMARC is beneficial, but rather, how we ensure that the valuable data it provides, particularly concerning IP addresses, doesn't inadvertently lead to GDPR compliance issues. Let's delve into the specifics of DMARC reports and their privacy implications.
DMARC generates two main types of reports: aggregate reports (RUA) and forensic reports (RUF). Each type contains different levels of detail, and consequently, different levels of potential privacy exposure related to IP addresses and other data.
Aggregate reports (RUA)
Aggregate reports provide a high-level overview of email authentication results for your domain. These XML-formatted reports are sent periodically (usually daily) to the email address specified in your DMARC record via the rua tag. They typically include information such as the sending IP address, the volume of messages, the results of SPF and DKIM authentication, and the DMARC policy applied. While IP addresses are present, these usually belong to the Mail Transfer Agents (MTAs) that sent the email, not individual end-users.
Forensic reports (RUF)
Forensic reports, on the other hand, are detailed failure reports sent immediately when an email fails DMARC authentication and the recipient server applies your DMARC policy. These reports, specified by the ruf tag, contain much more sensitive information. They often include full or partial copies of the failed email, including original email headers. These headers can contain personally identifiable information (PII) such as sender and recipient email addresses, subject lines, and potentially the originating IP address of the sender's device. This is where the primary GDPR concerns arise.
Report type
Contents
IP address context
GDPR sensitivity
Aggregate (RUA)
Daily summary, message volume, SPF/DKIM results.
Sending Mail Transfer Agent (MTA) IP addresses.
Low (generally not direct PII without additional context).
Originating IP addresses (can be end-user devices).
High (often contains direct PII like email addresses and user IPs).
IP addresses as personal data under GDPR
The General Data Protection Regulation (GDPR) defines personal data broadly as any information relating to an identified or identifiable natural person. This includes identifiers like names, identification numbers, location data, and online identifiers. Crucially, the GDPR explicitly states that online identifiers, which can include IP addresses, are considered personal data if they can be used to identify a natural person. This classification is vital for DMARC reporting.
The key here is whether the IP address, either alone or in combination with other information, can lead to the identification of an individual. For example, if an IP address is static and assigned to a single person, or if it's dynamic but combined with timestamps and other login data that allows for identification, it's considered PII. This is where the DMARC reporting discussion becomes complex.
When considering the specific types of DMARC reports, the GDPR implications vary significantly. For aggregate reports, the IP addresses typically belong to mail servers operated by Internet Service Providers (ISPs) or email service providers. These are generally not considered PII because they don't directly identify an individual. However, even with aggregate reports, you should be mindful of the data you collect and retain.
Forensic reports (RUF) are where the real privacy risk lies. Because they can contain original message headers and sometimes even parts of the email content, they are highly likely to include PII such as sender and recipient email addresses, and critically, the IP address of the individual's sending device. This level of detail means that collecting and storing RUF reports requires a clear legal basis under GDPR, and explicit consent is often necessary, which is rarely practical for unsolicited email failures.
Mitigating forensic report risks
Due to the significant privacy concerns, many organizations choose to avoid enabling forensic (RUF) reporting entirely. While RUF reports can offer granular insights into authentication failures, the privacy risks associated with collecting potentially sensitive user data, including IP addresses, often outweigh the benefits. If you must use them, anonymization and robust data handling policies are essential.
It's worth noting that if you use a third-party DMARC reporting service, you need to have a data processing agreement (DPA) in place. This agreement outlines how the service provider processes the data on your behalf and ensures they comply with GDPR requirements, especially concerning the handling of IP addresses and other potential PII in the reports.
Strategies for GDPR-compliant DMARC reporting
Safeguarding privacy while maintaining the benefits of DMARC visibility requires careful configuration. For aggregate reports, DMARC allows for a mechanism to anonymize IP addresses using the fo=1 tag, which is often mistakenly confused with a specific anonymization feature. The more common approach is for DMARC reporting tools to anonymize IP addresses before presenting them to you, typically by truncating the last octet or two.
Given the significant privacy risks associated with forensic reports (RUF), the most straightforward way to avoid GDPR issues is to simply not request them. The DMARC record syntax allows you to specify aggregate report recipients without including forensic report recipients. This approach ensures you get the valuable insights for monitoring and enforcement without collecting potentially sensitive user data.
While aggregate reports contain IP addresses of sending MTAs, these are generally not considered PII in isolation. Still, it's a best practice to choose DMARC reporting solutions that anonymize or pseudonymize this data where possible. For those looking to learn more about the different components of a DMARC record, our guide on the list of DMARC tags and their meanings can be a valuable resource. Additionally, you can find a simple guide to DMARC examples to help get started with a p=none policy, which is often the safest starting point for compliance.
Views from the trenches
Best practices
Always prioritize aggregate (RUA) reports for domain visibility over forensic (RUF) reports due to privacy concerns.
If using a DMARC reporting service, ensure they provide IP anonymization capabilities for aggregate reports.
Implement strong data retention policies for any DMARC report data collected, minimizing storage time.
Common pitfalls
Enabling forensic (RUF) reports without fully understanding the GDPR implications of collecting potentially sensitive PII.
Collecting and storing raw DMARC report data, including IP addresses, indefinitely without proper anonymization.
Not having a robust data processing agreement (DPA) with third-party DMARC reporting service providers.
Expert tips
Consider a DMARC policy of 'reject' to maximize protection, but only after thorough monitoring with aggregate reports to prevent legitimate email blocking.
Regularly review your DMARC reports to identify suspicious sending patterns and unauthorized use of your domain.
Don't rely solely on DMARC; combine it with SPF and DKIM for a comprehensive email authentication strategy.
Expert view
Expert from Email Geeks says virtually no one sends RUF data, and they haven't received one since 2018. They also mentioned not hearing about specific lawsuits related to this.
2024-03-15 - Email Geeks
Marketer view
Marketer from Email Geeks says there were some rulings in the mid-2010s regarding GDPR concerns about IP addresses being PII and their applicability to DMARC reporting.
2024-03-16 - Email Geeks
Balancing DMARC visibility and privacy compliance
The concerns around IP addresses in DMARC reporting and GDPR are legitimate, particularly when it comes to forensic reports. While IP addresses in aggregate reports (RUA) are generally less problematic, the highly detailed nature of forensic reports (RUF), including potential PII like sender and recipient email addresses and originating IP addresses, necessitates careful consideration and often avoidance. Prioritizing aggregate reports and implementing robust data anonymization practices are key to leveraging DMARC's benefits while maintaining GDPR compliance. Always ensure your DMARC service provider adheres to strict privacy standards and that you have a comprehensive understanding of what data is being collected and how it's handled. For additional resources, feel free to explore our guides on troubleshooting DMARC reports from major ISPs.
