How do ActiveCampaign and other ESPs handle DMARC records during custom return-path setup, and what are the potential issues?
Matthew Whittaker
Co-founder & CTO, Suped
Published 2 Jun 2025
Updated 18 Aug 2025
6 min read
Managing email authentication protocols like DMARC, SPF, and DKIM is crucial for achieving high email deliverability. While many Email Service Providers (ESPs) handle aspects of these records on your behalf, recent changes and practices, particularly concerning custom return-path setups, require careful attention. Understanding how your ESP, such as ActiveCampaign, manages these can prevent significant deliverability issues.
A notable development is the broader availability of custom return-path features across various ESP plans. This capability, previously often restricted to enterprise tiers, allows for better alignment of your sending domain with authentication records, which is vital for DMARC compliance. However, this flexibility also introduces new considerations for ensuring your DMARC records are correctly handled.
The return-path (also known as the Mail From or Bounce Address) is where bounce messages are sent. When an ESP sends emails on your behalf, they often use their own domain in the return-path. For DMARC, either the Return-Path domain (for SPF alignment) or the DKIM signing domain (for DKIM alignment) must align with the From domain. A custom return-path allows the return-path domain to be a subdomain of your primary sending domain, like bounces.yourdomain.com, enabling SPF alignment.
This SPF alignment is a key factor in passing DMARC authentication. While DMARC only requires either SPF or DKIM to align, having both aligned provides a more robust authentication posture. You can learn more about how SPF, DKIM, and DMARC affect deliverability when using a third-party ESP.
The ability to customize the return-path helps senders control their reputation by ensuring that all parts of the email, including bounces, are associated with their domain. This consistency can positively influence how recipient mail servers perceive your emails, contributing to better inbox placement.
Benefit of custom return-path
A custom return-path allows for SPF alignment with your sending domain, significantly enhancing DMARC authentication. This strengthens your sender reputation and improves email deliverability by ensuring a consistent domain association across all email components, from the From address to the return-path.
ESPs and DMARC record management
ESPs like ActiveCampaign generally guide users through setting up necessary DNS records such as SPF and DKIM. They typically provide specific CNAME or TXT records to publish, which delegate authentication to the ESP's sending infrastructure. However, their approach to DMARC records can sometimes differ, leading to confusion for users, particularly those with existing DMARC policies.
Some ESPs might present a generic DMARC record to users during the setup of a custom return-path, even if a legitimate DMARC record already exists for the domain. This can lead to a common issue: inadvertently publishing a duplicate DMARC record. While some ESPs, especially those with advanced API integrations, are improving to detect and respect existing records, it is not universally applied. For instance, you can find further information on how Postmark handles DMARC in their troubleshooting guide.
The issue extends beyond just DMARC. In some cases, automated DNS setup via API might delete or overwrite existing DKIM records, removing important comments or tags that were previously in place. While the new records might be functionally identical, the loss of metadata can complicate future management and troubleshooting.
Typical ESP setup guidance
Provides records: ESPs typically give you specific SPF and DKIM records to add to your DNS.
DMARC suggestion: May suggest adding a new DMARC record, sometimes generic, even if one already exists.
Automated DNS: Some offer API integrations to automate DNS record creation or modification.
Optimal DMARC practice
Prevent duplicates: Always check for existing DMARC records to avoid publishing a second one.
Preserve records: Ensure automated systems do not overwrite or remove important DNS record metadata.
Manual review: Manually verify all DNS changes after any ESP-driven setup process.
Common challenges and pitfalls
The primary issue stemming from improper DMARC setup during custom return-path configuration is failed email delivery. A duplicate DMARC record will invalidate your domain's authentication, leading to emails being rejected by recipient servers or sent straight to spam folders. This can severely impact your sender reputation and campaign performance. You can read about how to troubleshoot DMARC failures to mitigate their impact.
Another pitfall is when an ESP's automated process replaces existing DNS records without preserving valuable information. For example, if your DKIM records were set up with specific comments for organizational purposes, an automated update might remove these, making future management challenging. Similarly, if your DMARC record had specific reporting addresses or policy settings, a generic replacement could undo your carefully configured policy.
These issues highlight the importance of understanding the underlying mechanics of email authentication, including how the From domain record impacts SPF and DMARC. Always verify your DNS records after any changes made by an ESP. This vigilance helps catch potential misconfigurations before they lead to deliverability problems or being placed on a blocklist (or blacklist).
To ensure your email authentication remains robust, it is essential to take an active role in managing your DMARC records. While ESPs simplify the process, blindly accepting their suggested DNS entries can lead to problems. Always cross-reference their instructions with your existing DNS configuration, especially concerning DMARC.
Utilize DNS checking tools to confirm that your DMARC, SPF, and DKIM records are correctly published and aligned. This proactive approach helps detect issues like duplicate DMARC records or SPF authentication failures before they impact your email campaigns. These tools can provide insights into your domain's authentication health. For a comprehensive overview, refer to this simple guide to DMARC, SPF, and DKIM.
Finally, understand the implications of your DMARC policy. Starting with a p=none policy allows you to monitor DMARC reports without affecting email delivery, providing valuable insights. As you gain confidence, you can gradually transition to p=quarantine or p=reject to enforce stricter policies and protect your domain from spoofing. You can find out more about how to safely transition your DMARC policy.
Key DMARC setup checks
Before setup: Review your current DNS records, specifically for any existing DMARC entries.
During setup: If your ESP suggests a new DMARC record, confirm you don't already have one.
After setup: Use a DNS checker to verify all authentication records for proper alignment.
Views from the trenches
Best practices
Always verify DNS records after any automated setup by an ESP.
Prioritize using a custom return-path to enable SPF alignment for DMARC.
Maintain backup copies of your DNS zone files before making major changes.
Common pitfalls
Adding a second DMARC record when one already exists can cause configuration problems.
Allowing automated API DNS updates without checking for existing records and comments.
Overlooking the need for DMARC alignment when setting up custom return-paths.
Expert tips
Review ESP documentation for DMARC handling during custom return-path setup.
Implement DMARC reporting to gain visibility into your email authentication results.
Consult with a DMARC professional if your setup is complex or you encounter persistent issues.
Expert view
Expert from Email Geeks says: ActiveCampaign now offers custom return-path functionality for all plans, which has proven effective for multiple clients.
2024-02-02 - Email Geeks
Expert view
Expert from Email Geeks says: DNS checker tools should accurately validate DMARC records without prompting users to create duplicates if a valid record already exists.
2024-02-02 - Email Geeks
Enhancing email authentication and deliverability
The evolution of ESP features, such as ActiveCampaign's expanded custom return-path options, marks a positive step towards empowering senders with better authentication control. By enabling SPF alignment, these features enhance DMARC compliance and overall email deliverability. However, the responsibility ultimately lies with senders to ensure these powerful tools are correctly configured.
Proactive management of your DNS records, including thorough verification and understanding of DMARC policies, is essential. This diligence will help you leverage custom return-paths effectively, maintain a strong sender reputation, and ensure your emails consistently reach their intended inboxes without encountering DMARC failures or ending up on a blacklist (or blocklist).
