What does DMARC loop detection mean and how to resolve it?

Email marketer from Mailhardener recommends creating a specific mailbox for DMARC reports (e.g., dmarc@yourdomain.com) and ensuring this mailbox does not have DMARC enabled. This prevents the reports from triggering further DMARC checks and creating a loop.

Marketer from Email Geeks indicates encountering the same issue from different services and suggests it could be a nameserver issue. They also advise against implementing DMARC without actively monitoring reports or having an alert system.

Email marketer from Reddit explains the main solution to the DMARC loop problem is to set up a dedicated mailbox only to receive DMARC reports, and configure the receiving mailbox to not have a DMARC policy itself.

Email marketer from StackExchange explains that a DMARC loop happens when DMARC aggregate reports are sent from a mailbox which also has a DMARC policy. The initial email will fail the DMARC authentication process and a DMARC report will be sent, because the report sending mailbox has a DMARC policy, that also fails DMARC, which causes another report to be sent to the original sender, creating the loop.

Email marketer from StackExchange recommends to check that the RUA tag is not pointing to an inbox with a valid DMARC policy, as this is the leading cause of reporting loops. You should change it to point to an inbox which does not have any DMARC policy.

Email marketer from AuthSMTP warns about common DMARC misconfigurations, such as using a support or helpdesk email address as the reporting address. This can overwhelm the support team with XML reports and potentially create a loop if the helpdesk system automatically generates responses based on incoming emails.

Email marketer from EasyDMARC promotes using a DMARC monitoring platform to receive, analyze, and understand DMARC reports. These platforms often provide tools to identify and address potential loop issues by automatically suppressing redundant reports and identifying the sources of the loop.

Email marketer from MXToolbox advises using their DMARC record checking tool to identify potential issues with your DMARC setup. This tool can highlight problems such as incorrect syntax, missing tags, or misconfigured reporting addresses that could contribute to a loop.

Email marketer from DNS records highlights that any incorrect syntax in DNS records can cause issues with DMARC, and the reports can highlight the exact issues within your records. Ensuring that your domain has valid syntax avoids any loop issues when sending emails.

Email marketer from EmailDudes Forum user suggests using a DMARC reporting service or tool that automatically analyzes and summarizes the reports. This can help identify the source of the loop and take appropriate action, without manually sifting through the raw XML data.

Expert from Email Geeks suspects a MediaTemple DNS issue and agrees with LoriBeth that DMARC monitoring is essential, cautioning against sending reports to a support inbox.

Expert from Word to the Wise explains that if you implement DMARC monitoring, it is important to ensure that your server has the capacity to receive, analyse, and understand the DMARC reports being generated. DMARC reports can highlight issues such as DMARC reporting loops and can allow you to resolve them.

Expert from Email Geeks says the DMARC record looks ok and the loop detection could have been a temporary issue, stating that everything looks fine now.

Documentation from DMARC.org explains that a DMARC loop occurs when a mail server encounters a DMARC policy that directs it to send failure reports to an address that is also subject to DMARC protection. This can create an infinite loop of reports being generated and sent between servers. The solution is to ensure that reporting addresses are either exempt from DMARC checks or configured to handle reports in a way that doesn't trigger further DMARC failures.

Documentation from Google Workspace explains that administrators should carefully configure their DMARC policies (p=none, p=quarantine, or p=reject) and monitor the resulting reports. Setting an overly aggressive policy (e.g., p=reject) without proper monitoring can lead to legitimate emails being blocked and potential reporting loops.

Documentation from RFC7489 describes that DMARC implementations should include mechanisms to detect and suppress report loops. This might involve tracking the origin of reports and avoiding sending further reports in response to those. Additionally, the specification recommends limiting the number of reports generated for a single message to prevent resource exhaustion.

Documentation from Microsoft Learn outlines how to configure DMARC for Exchange Online. It emphasizes the importance of properly setting up SPF and DKIM before enabling DMARC and carefully managing the reporting options to avoid loops.

Documentation from Proofpoint says that a company should ensure that there are adequate mechanisms in place to detect any DMARC reporting loop issues. Proofpoint themselves offer products to analyse and flag any potential issues with DMARC setup.