Why am I receiving multiple DMARC reports from the same domain?
Summary
What email marketers say11Marketer opinions
Email marketer from StackExchange shares that the quantity of reports you receive reflects the number of distinct entities processing mail from your domain. Different organizations means multiple reports.
Email marketer from Email Geeks explains they send a report per receiving domain.
Email marketer from URIports suggests that seeing multiple reports for a domain is a typical occurrence. What's important is diving into the actual messages and identifying what is causing the DMARC report to be generated. Check the headers and source IPs, and also note whether these are originating from a third-party sender.
Email marketer from Email Geeks clarifies that DMARC reports show authentication results for DKIM and SPF, along with the DMARC policy evaluation. SPF failing in the policy section means the SPF domain doesn't align with the header_from domain, even if SPF authentication passed.
Email marketer from EasyDMARC shares that the same sender can send you multiple reports if they receive emails from your domain with different authentication results or different source IPs. They also will send multiple if you have more than one domain.
Email marketer from Email Geeks, Marcel Becker & Faisal Misle, explain that the subject of the reporting email contains the reporting domain (submitter) and the filename of the report contains that as well. Each report is for a different receiving domain.
Email marketer from Email Geeks shares that recipients send one DMARC report per receiving domain and if the same RUA is used for multiple domains, multiple reports will be sent.
Email marketer from Reddit (r/sysadmin) explains that if your domain sends email from different IPs, receivers create DMARC reports for each IP range that are then sent to the report-uri.
Email marketer from Mailhardener explains that receiving multiple DMARC reports from the same domain, is usually because each report covers a different subset of your mail stream (different source IPs, different authenticating domains) and/or the reporting period is aggregated.
Email marketer from Valimail explains that if you have multiple subdomains sending email, and each subdomain is treated as a separate entity by the receiving mail server, you will receive separate DMARC reports for each subdomain.
Email marketer from HelpSystems (formerly Agari) shares that high DMARC report volume can arise from multiple factors: large email volume, use of numerous third-party senders, and variations in email authentication practices across different senders. Each receiver generates a report, which means multiple sources each cause a separate report.
What the experts say2Expert opinions
Expert from Word to the Wise notes that one common problem is seeing reports from domains that don't send mail. It is important to review and monitor DMARC reports.
Expert from Word to the Wise explains that multiple DMARC reports from the same domain can be caused by ESPs using different mail streams for different messages.
What the documentation says3Technical articles
Documentation from RFC7489 specifies that aggregate reports are typically sent on a periodic basis (e.g., daily) and contain summarized data about the authentication results seen by the reporting organization. Therefore, you can expect multiple reports over time.
Documentation from DMARC.org explains that DMARC reports are typically sent once per day, per sending domain, by each organization receiving mail from that domain. However, the exact frequency may vary depending on the reporting policies of the receiver.
Documentation from Google Workspace Admin Help explains if you use multiple email service providers, each ESP may generate its own DMARC report, leading to multiple reports from what appears to be the same domain. Google also sends separate reports for different date ranges.