How to configure Mailman with DMARC and handle Gmail deliverability issues?

Summary

Configuring Mailman with DMARC and addressing Gmail deliverability issues requires a multi-faceted approach. Key strategies include header rewriting within Mailman, although ARC (if supported) is a more robust alternative. Implementing proper email authentication mechanisms such as SPF, DKIM, and DMARC is crucial for verifying sender identity and preventing email spoofing. A phased DMARC deployment, starting with a monitoring policy (p=none), is recommended to gather data and identify legitimate email sources before enforcing stricter policies. Adherence to Gmail's bulk sender guidelines, along with maintaining clean and segmented email lists, is essential for optimizing deliverability. Monitoring tools like Google Postmaster Tools are invaluable for diagnosing deliverability problems and tracking domain reputation. Finally, staying informed about the nuances of Gmail's DMARC handling and proactively addressing bounces and spam complaints ensures a positive sender reputation and improved inbox placement.

Key findings

  • Header Rewriting in Mailman: Mailman can be configured with DMARC using header rewriting, although ARC offers a more robust alternative if supported.
  • Importance of SPF, DKIM, and DMARC: Implementing SPF, DKIM, and DMARC is essential for email authentication, preventing spoofing, and ensuring deliverability.
  • Phased DMARC Deployment: A phased DMARC deployment, starting with a monitoring policy (p=none), allows for data gathering and prevents unintended deliverability issues.
  • Gmail's DMARC Handling: Gmail sometimes enforces stricter DMARC policies than domains explicitly define, requiring comprehensive header rewriting.
  • Google Postmaster Tools: Google Postmaster Tools provides valuable insights into deliverability problems and domain reputation with Gmail.
  • List Hygiene and Segmentation: Maintaining a clean and segmented email list improves engagement and prevents spam complaints.

Key considerations

  • Choose between Header Rewriting and ARC: Evaluate the trade-offs between header rewriting and ARC in Mailman based on support, complexity, and effectiveness.
  • Monitor DMARC Reports: Continuously monitor DMARC reports to identify authentication failures and address deliverability issues.
  • Comply with Gmail's Guidelines: Strictly adhere to Gmail's bulk sender guidelines to avoid being flagged as spam.
  • Implement Feedback Loops: Set up feedback loops to address complaints and improve sender reputation.
  • Warm Up IP Address: Warming up the IP address gradually establishes a positive sender reputation with Gmail.
  • Regularly Review Metrics: Regularly review deliverability metrics (bounce rates, spam complaints, engagement) to identify and address issues promptly.

What email marketers say
7Marketer opinions

Configuring Mailman with DMARC and resolving Gmail deliverability issues involves several key strategies. A common approach is to rewrite the From: header to align with DMARC policies, ensuring SPF and DKIM are correctly configured. Monitoring tools like Google Postmaster Tools are recommended for diagnosing deliverability problems. Adherence to Gmail's bulk sender guidelines and proactive list hygiene are essential, including implementing feedback loops and removing unengaged subscribers. Best practices emphasize proper authentication methods (SPF, DKIM, DMARC), maintaining clean and segmented email lists, and consistently monitoring engagement metrics. A phased DMARC implementation, starting with a monitoring policy, is advised. Avoiding spam triggers, warming up IP addresses and regularly reviewing metrics further aid in optimizing email delivery.

Key opinions

  • Header Rewriting: Rewriting the From: header is a common solution for DMARC compliance in Mailman.
  • Authentication: Proper SPF, DKIM, and DMARC configuration are crucial for authentication and improved deliverability.
  • Google Postmaster Tools: Using Google Postmaster Tools helps monitor and diagnose deliverability issues with Gmail.
  • List Hygiene: Maintaining a clean email list by removing unengaged subscribers and managing complaints improves deliverability.
  • Phased DMARC Implementation: A phased approach to DMARC implementation, starting with a monitoring policy, helps avoid deliverability problems.

Key considerations

  • DMARC Policy: Carefully consider the DMARC policy of the sending domain and ensure alignment with SPF and DKIM records.
  • Gmail Guidelines: Adhere to Gmail's bulk sender guidelines to avoid being flagged as spam.
  • Engagement Metrics: Monitor engagement metrics like open rates and click-through rates to identify and address deliverability issues.
  • Sender Reputation: Maintain a good sender reputation by avoiding spam trigger words and warming up the IP address.
  • Feedback Loops: Implement feedback loops to handle complaints and promptly address any issues raised by subscribers.
Marketer view

Email marketer from Mailgun shares that improving deliverability includes proper SPF, DKIM, and DMARC setup, maintaining a clean list, monitoring bounce rates, and using a dedicated IP address. Regularly reviewing and analyzing deliverability metrics helps identify and address any issues.

April 2024 - Mailgun
Marketer view

Email marketer from Litmus explains the common challenges with DMARC configuration and enforcement. They suggest using a phased approach, starting with a 'p=none' policy to monitor email streams before implementing stricter policies like 'p=quarantine' or 'p=reject'. Analyzing DMARC reports is vital for identifying legitimate email sources that may not be properly authenticated.

June 2023 - Litmus
Marketer view

Email marketer from EmailDiscussions recommends monitoring Gmail's bulk sender guidelines and ensuring that the mailing list complies with these guidelines. They also suggest implementing feedback loops to handle complaints and removing subscribers who are not engaging with the emails. Keeping list hygiene is essential for good delivery.

May 2023 - EmailDiscussions
Marketer view

Email marketer from Mailjet shares email deliverability best practices including setting up proper authentication methods like SPF, DKIM, and DMARC. They also highlight the importance of maintaining a clean email list and segmenting the audience. Monitoring engagement metrics and promptly addressing bounces and spam complaints are also recommended.

July 2022 - Mailjet
Marketer view

Email marketer from SendPulse answers that to improve email delivery, it's essential to authenticate your domain with SPF, DKIM, and DMARC. It's also important to maintain a good sender reputation, avoid using spam trigger words, and segment the email list for more targeted messaging.

October 2023 - SendPulse
Marketer view

Email marketer from Reddit recommends checking the DMARC policy of the sending domain and ensuring that SPF and DKIM records are properly configured. They also suggest using Google Postmaster Tools to monitor deliverability issues and identify any authentication problems. They recommend warming up the IP address to increase the sender reputation.

May 2023 - Reddit
Marketer view

Email marketer from StackOverflow suggests configuring your mail server to rewrite the From: header for messages originating from the mailing list. This involves changing the sender to an address within your domain that is DMARC compliant. They emphasize the importance of testing and monitoring DMARC reports.

February 2025 - StackOverflow

What the experts say
4Expert opinions

Configuring Mailman with DMARC and handling Gmail deliverability issues involves rewriting headers, deploying DMARC with a monitoring-first approach, and implementing SPF, DKIM, and DMARC for email authentication. Header rewriting is essential for Mailman to work with DMARC, although ARC offers a more robust solution (if supported). Gmail may treat domains as having stricter DMARC policies than they actually do, necessitating comprehensive header rewriting. DMARC deployment should start with a monitoring policy to gather data before implementing stricter policies. Proper configuration of SPF, DKIM, and DMARC is critical for verifying sender identity, preventing spoofing, and maintaining a good sender reputation, all improving deliverability.

Key opinions

  • Header Rewriting: Header rewriting is crucial for Mailman DMARC compliance but has limitations.
  • Gmail DMARC Behavior: Gmail may enforce stricter DMARC policies than advertised.
  • Phased DMARC Deployment: DMARC deployment requires a monitoring phase before enforcement.
  • Email Authentication: SPF, DKIM, and DMARC are essential for email authentication and deliverability.

Key considerations

  • ARC Support: Evaluate ARC support in Mailman as an alternative to header rewriting.
  • Comprehensive Rewriting: Rewrite headers even if domains don't have explicit p=quarantine/reject policies due to Gmail's behavior.
  • Data Gathering: Thoroughly analyze DMARC reports during the monitoring phase to identify legitimate email sources.
  • Sender Reputation: Focus on maintaining a positive sender reputation through proper email authentication.
Expert view

Expert from Email Geeks explains that header rewrite is the way to go to get Mailman to work with DMARC, despite some people disliking the idea of having to do it. ARC fixes this, but ARC support in Mailman is unknown and has complexities.

September 2022 - Email Geeks
Expert view

Expert from Spam Resource explains that DMARC deployment requires careful planning and execution. They suggest starting with a monitoring policy (p=none) to gather data and identify legitimate email sources before moving to stricter policies (p=quarantine or p=reject). They also highlight the importance of analyzing DMARC reports to ensure proper authentication and address any deliverability issues.

May 2021 - Spam Resource
Expert view

Expert from Word to the Wise responds that implementing email authentication protocols like SPF, DKIM, and DMARC is critical for ensuring deliverability. These protocols help verify the sender's identity and prevent spoofing, which can negatively impact inbox placement. Ensuring proper configuration of these records is crucial for maintaining a good sender reputation.

January 2023 - Word to the Wise
Expert view

Expert from Email Geeks shares a gotcha with DMARC, in that Gmail sometimes treats domains as if they have p=quarantine/reject, even if they don't. Rewriting headers only when finding p=q/r might still lead to deliverability problems with Gmail.

August 2023 - Email Geeks

What the documentation says
6Technical articles

Configuring Mailman with DMARC and handling Gmail deliverability issues involves implementing proper email authentication mechanisms. Mailman can use header rewriting or ARC to comply with DMARC. DMARC, in conjunction with SPF and DKIM, helps prevent email spoofing by authenticating emails and enforcing domain policies. Gmail delivery is improved by ensuring proper authentication, avoiding unwanted mail, and adhering to Gmail's guidelines. Google Postmaster Tools can be used to monitor domain reputation. DKIM provides a method for verifying sender identity and message integrity, while SPF allows domain owners to specify authorized mail servers. DMARC unifies SPF and DKIM for policy enforcement, allowing domain owners to control how receivers handle unauthenticated messages.

Key findings

  • Mailman DMARC Options: Mailman supports header rewriting and ARC for DMARC compliance.
  • DMARC Overview: DMARC prevents spoofing and works with SPF and DKIM for authentication.
  • Gmail Delivery: Proper authentication and compliance with Gmail guidelines improve delivery.
  • DKIM Functionality: DKIM verifies sender identity and message integrity through cryptographic signatures.
  • SPF Functionality: SPF authorizes mail servers to send emails on behalf of a domain.
  • DMARC Unification: DMARC unifies SPF and DKIM for policy enforcement.

Key considerations

  • Header Rewriting vs ARC: Choose between header rewriting and ARC for Mailman DMARC compliance based on support and complexity.
  • Monitoring DMARC Reports: Monitor DMARC reports to identify and address deliverability issues.
  • Gmail Guidelines Adherence: Strictly adhere to Gmail's sender guidelines to avoid deliverability problems.
  • Authentication Implementation: Ensure correct implementation of SPF, DKIM, and DMARC for robust email authentication.
  • Postmaster Tools Usage: Utilize Google Postmaster Tools to monitor domain reputation and identify potential deliverability issues.
Technical article

Documentation from RFC 7208 specifies the Sender Policy Framework (SPF) for email authentication. SPF allows domain owners to specify which mail servers are authorized to send email on behalf of their domain, helping to prevent email spoofing and improve deliverability.

May 2021 - RFC Editor
Technical article

Documentation from dmarc.org explains the general concepts of DMARC and its role in preventing email spoofing. It discusses how DMARC works in conjunction with SPF and DKIM to authenticate emails and enforce policies. The site also emphasizes the importance of monitoring DMARC reports to identify and address deliverability issues.

September 2023 - dmarc.org
Technical article

Documentation from GNU Mailman explains that Mailman can be configured to work with DMARC by using header rewriting or ARC. Header rewriting involves modifying the From: header of messages sent through the mailing list to align with the DMARC policy of the sending domain. ARC support helps in preserving authentication results as the message passes through intermediate servers.

March 2023 - GNU Mailman
Technical article

Documentation from Google Workspace Admin Help explains that to improve email delivery to Gmail, ensure proper authentication (SPF, DKIM, DMARC), avoid sending unwanted mail, and follow Gmail's sender guidelines. Also, the documentation points out using Postmaster Tools to check the domain reputation and identify potential issues that may affect delivery rates.

April 2021 - Google Workspace Admin Help
Technical article

Documentation from RFC 7489 specifies the Domain-based Message Authentication, Reporting, and Conformance (DMARC) protocol. DMARC builds upon SPF and DKIM to provide a unified mechanism for email authentication and policy enforcement, enabling domain owners to control how email receivers handle messages that fail authentication checks.

April 2021 - RFC Editor
Technical article

Documentation from RFC 6376 specifies the DomainKeys Identified Mail (DKIM) signature method for email authentication. DKIM allows senders to cryptographically sign their messages, providing a mechanism for verifying the sender's identity and message integrity.

March 2022 - RFC Editor