Summary
DMARC loop detection signifies a recurring issue where failure reports are sent to a mailbox also subject to DMARC policies, creating an endless cycle. Resolution involves setting up a dedicated reporting mailbox without DMARC enabled, actively monitoring DMARC reports, ensuring DNS records have valid syntax, and avoiding support inboxes for DMARC reports. Temporary issues and nameserver problems might be initial indicators, but proper configuration and continuous oversight are essential.
Key findings
- Cause of Loops: DMARC loops occur when failure reports are sent to a mailbox with its own DMARC policy.
- DNS Impact: Nameserver problems and incorrect DNS syntax can contribute to loop detection.
- Dedicated Mailbox Solution: A dedicated mailbox for DMARC reports, without a DMARC policy, resolves loop issues.
- RUA tag: The RUA tag should not point to a DMARC protected inbox.
Key considerations
- Active Monitoring: Continuous DMARC monitoring with alert systems is crucial.
- Support Inbox Avoidance: Avoid using support inboxes for DMARC reports to prevent overload and loops.
- Proper Configuration: Correctly configure SPF and DKIM before enabling DMARC, carefully managing reporting options.
- DMARC Tools: Employ DMARC reporting services and record checking tools to maintain optimal configuration.
- Server Capacity: Ensure servers have sufficient capacity to process and analyze DMARC reports.
What email marketers say
10 marketer opinions
A DMARC loop occurs when DMARC aggregate reports are sent to a mailbox that also has a DMARC policy, causing a continuous cycle of report generation. Resolving this involves configuring a dedicated mailbox specifically for DMARC reports without a DMARC policy enabled. Additionally, using DMARC reporting tools, checking DNS record syntax, and avoiding support inboxes as reporting addresses are recommended practices.
Key opinions
- Cause of Loops: DMARC loops are primarily caused when DMARC reports are sent to a mailbox that is also subject to DMARC policies.
- Nameserver Issues: Encountering DMARC issues can sometimes point to underlying nameserver problems.
- Dedicated Mailbox: Setting up a dedicated mailbox without a DMARC policy is essential to avoid report loops.
- Reporting Tools: Utilizing DMARC reporting services and tools is valuable for analyzing and summarizing reports to identify and resolve loop sources.
- DNS Syntax: Incorrect DNS record syntax can lead to DMARC issues, highlighting the importance of valid syntax.
- RUA Tag: Ensure the RUA tag isn't pointing to an inbox with a DMARC policy.
Key considerations
- Active Monitoring: DMARC implementation should always include active monitoring and alert systems.
- Reporting Address: Avoid using support or helpdesk email addresses for DMARC reports to prevent overwhelming the support team and potential loop creation.
- Record Checking: Regularly check DMARC records for potential misconfigurations using available tools.
- DMARC Platforms: Consider using a DMARC monitoring platform to aid in understanding and addressing report issues.
Marketer view
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.
27 Oct 2021 - Mailhardener
Marketer view
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.
25 Oct 2021 - Email Geeks
What the experts say
3 expert opinions
DMARC loop detection, while sometimes a temporary DNS issue, often points to deeper configuration problems. Experts emphasize the importance of active DMARC monitoring to analyze generated reports and address potential issues. A key consideration is avoiding the use of support inboxes for receiving DMARC reports.
Key opinions
- Temporary Issues: Loop detection can sometimes be a temporary DNS issue.
- DNS Problems: Loop detection can be a sign of MediaTemple DNS issue.
- Monitoring Importance: Active DMARC monitoring is crucial for understanding and addressing loop detection.
- Report Analysis: Servers must have the capacity to analyze DMARC reports to resolve loop issues.
Key considerations
- Support Inboxes: Avoid using support inboxes for receiving DMARC reports.
Expert view
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.
29 Apr 2023 - Email Geeks
Expert view
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.
17 May 2024 - Word to the Wise
What the documentation says
5 technical articles
DMARC loops arise when failure reports are sent to an address that is itself subject to DMARC protection, creating an infinite reporting cycle. Solutions involve exempting reporting addresses from DMARC checks and carefully managing reporting options. DMARC implementations should also include mechanisms to detect and suppress loops, and administrators should avoid aggressive policies without monitoring. Setting up SPF and DKIM correctly before enabling DMARC is crucial to prevent these issues.
Key findings
- Loop Cause: DMARC loops occur when failure reports are sent to an address also subject to DMARC protection.
- Infinite Cycle: This creates an infinite loop of reports being generated and sent between servers.
- Loop Suppression: DMARC implementations should detect and suppress report loops to prevent resource exhaustion.
Key considerations
- Exemptions: Ensure reporting addresses are exempt from DMARC checks.
- Policy Configuration: Carefully configure DMARC policies and monitor resulting reports to avoid issues.
- Aggressive Policies: Avoid overly aggressive policies (p=reject) without proper monitoring.
- Pre-requisites: Set up SPF and DKIM correctly before enabling DMARC.
Technical article
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.
22 May 2024 - DMARC.org
Technical article
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.
28 Oct 2022 - Google Workspace Admin Help
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