Summary
The collective advice leans towards using separate subdomains for each Email Service Provider (ESP) due to improved reputation isolation. While sharing subdomains has potential for shared mail stream reputation, the benefits of segmentation are often favored. Proper authentication via SPF, DKIM, and DMARC is vital regardless of subdomain strategy, although strict DMARC alignment isn't always essential. Segmentation aids in tracking, management, and control, enabling different DMARC policies for varied traffic. Subdomain variations are useful for deliverability testing. A consistent sender ID is crucial, and technical documentation outlines the setup and management aspects. Automation of DMARC reports is recommended.
Key findings
- Reputation Isolation: Different subdomains isolate sending reputations; issues with one ESP are less likely to impact others.
- Enhanced Management: Segmentation via subdomains enables granular tracking and better overall email stream management.
- Authentication is Key: SPF, DKIM, and DMARC are critical, though strict DMARC alignment isn't universally necessary.
- Testing Opportunities: Subdomain variations offer a method for testing deliverability and ESP impact.
- Automation Importance: DMARC report automation is key for effective monitoring.
Key considerations
- Reputation Tradeoffs: Consider the pros and cons of shared versus isolated reputations.
- Authentication Setup: Ensure proper SPF, DKIM, and DMARC implementation.
- Sender ID Consistency: Maintain a consistent and recognizable sender ID.
- Policy Tailoring: Implement DMARC policies tailored to specific email traffic types.
- DNS Management: Manage DNS records accurately for each subdomain.
- Testing: Test subdomain usage to ensure optimum delivery.
What email marketers say
8 marketer opinions
The consensus among email marketers is that using separate subdomains for each Email Service Provider (ESP) is generally recommended. This practice allows for isolation of sending reputations, meaning if one ESP experiences deliverability issues, it's less likely to negatively affect the reputation of other ESPs. Segmentation via subdomains also enables more granular tracking, better overall management of diverse email streams, and provides a level of control, especially important when ESPs have varying sending practices.
Key opinions
- Reputation Isolation: Using separate subdomains isolates sending reputations, preventing deliverability problems with one ESP from affecting others.
- Granular Tracking: Dedicated subdomains allow for more specific tracking and monitoring of each ESP's performance.
- Improved Management: Segmentation using subdomains provides better overall management of diverse email streams from different ESPs.
- Enhanced Control: Separate subdomains offer greater control over sending practices, particularly beneficial when ESPs have varying approaches.
Key considerations
- ESP Sending Practices: Consider the sending practices of each ESP and how they might impact deliverability.
- Domain Reputation: Protect your primary domain's reputation by isolating potential deliverability issues to specific subdomains.
- Segmentation Strategy: Develop a clear segmentation strategy based on message type and/or ESP to optimize deliverability.
- Shared IP Risk: Be aware of the risk of shared IP addresses when using multiple ESPs and consider how subdomains can help mitigate this risk.
Marketer view
Email marketer from GMass explains that using multiple domains to improve your deliverability could improve your results, and having a separate domain for transactional and marketing emails to improve trust.
23 Sep 2022 - GMass
Marketer view
Email marketer from Reddit shares the opinion that using separate subdomains provides a level of isolation and control. If one subdomain gets blacklisted, it won't necessarily impact the others. This is especially important when using multiple ESPs with potentially varying sending practices.
6 Jul 2023 - Reddit
What the experts say
5 expert opinions
Experts have varying perspectives on subdomain usage with multiple ESPs. Some suggest there are pros and cons to sharing subdomains, primarily related to shared reputation. Authentication through SPF and DKIM, with DMARC alignment, is crucial regardless of subdomain strategy, though DMARC alignment isn't strictly essential, nor are different subdomains to achieve it. Isolation of sending reputations is a key benefit of using separate subdomains, reducing the impact of deliverability issues on other ESPs. Furthermore, subdomain variations can be used for deliverability testing and measuring the impact of different ESPs, while DMARC reporting should be automated to a different address than the human-managed reply-to address.
Key opinions
- Shared Reputation: Using the same subdomains across multiple ESPs leads to a stronger sharing of mail stream reputation.
- Authentication Importance: SPF and DKIM authentication are critical, and DMARC alignment is a desirable but not strictly necessary goal, regardless of subdomain configuration.
- Reputation Isolation: Separate subdomains allow for better isolation of sending reputations, minimizing the impact of deliverability issues with one ESP on others.
- Deliverability Testing: Subdomain variations can be used to test and measure the impact of different sending practices, including the use of different ESPs, on deliverability.
- Automated DMARC Reporting: DMARC reporting should be directed to an automated system, separate from the human-managed reply-to address.
Key considerations
- Reputation Trade-offs: Carefully consider the trade-offs between shared reputation and isolation when deciding whether to use the same or different subdomains.
- Authentication Setup: Ensure proper SPF and DKIM authentication is in place, and evaluate the benefits and complexity of DMARC alignment.
- Deliverability Testing: Conduct thorough deliverability testing to assess the impact of your subdomain and ESP configuration.
- DMARC Configuration: Properly configure DMARC to receive reports and monitor potential deliverability issues. Direct reports to an automated system.
Expert view
Expert from Spam Resource explains that using different subdomains for each ESP allows for better isolation of sending reputations. If one ESP has deliverability problems, it's less likely to negatively impact the reputation of the other ESPs.
9 Dec 2024 - Spam Resource
Expert view
Expert from Email Geeks explains that it is desirable for the rua/ruf mailto to be different than the from: email used. Reply emails should go to a human, while DMARC reports should go to automation.
9 Oct 2021 - Email Geeks
What the documentation says
5 technical articles
Technical documentation emphasizes the importance of properly configured subdomains for email deliverability, sender identification, and security. A consistent sender ID, as highlighted by RFC, builds trust. Google Workspace documentation illustrates subdomain setup within its ecosystem. Microsoft details SPF record configuration, crucial for subdomain authentication and preventing spoofing. DMARC.org explains that different DMARC policies can be implemented for various email traffic types using separate subdomains. Cloudflare provides guidance on DNS settings, including SPF, DKIM, and DMARC records, for managing subdomains.
Key findings
- Sender Identification: A consistent and identifiable sender ID, facilitated by a clear and trustworthy domain (and its subdomains), builds recipient trust.
- Technical Feasibility: Setting up and managing multiple subdomains for email is technically feasible, as demonstrated by Google Workspace documentation.
- Authentication is Critical: Properly configuring SPF records for each subdomain is essential for authentication, preventing spoofing, and ensuring deliverability.
- Policy Flexibility: Using separate subdomains allows the implementation of different DMARC policies for different types of email traffic.
- DNS Configuration: Accurate DNS configuration, including SPF, DKIM, and DMARC records, is necessary for effective subdomain management.
Key considerations
- Consistent Sender ID: Maintain a consistent and recognizable sender ID across all subdomains to build recipient trust.
- Authentication: Prioritize proper authentication through SPF, DKIM, and DMARC for each subdomain to ensure deliverability and prevent spoofing.
- DMARC policies: Consider implementing DMARC policies tailored to the specific types of email traffic sent from each subdomain.
- DNS Management: Ensure accurate and up-to-date DNS records for each subdomain to maintain proper email routing and authentication.
Technical article
Documentation from Cloudflare details the DNS configuration needed for managing subdomains. It shows how to configure SPF, DKIM and DMARC records.
23 Jan 2023 - Cloudflare
Technical article
Documentation from DMARC.org describes how DMARC policies can be applied to subdomains. Using separate subdomains can allow you to implement different DMARC policies for different types of email traffic.
1 Aug 2024 - DMARC.org
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