Summary
Experts and documentation sources widely recommend using a subdomain for SPF records in email marketing. This practice shields the primary domain's reputation by isolating marketing emails and any associated deliverability issues. It is considered bad practice to set up SPF for an ESP at the root domain; instead, the SPF should align with the domain used in the 5321.from address (envelope sender) and EHLO. Subdomains enable independent management of SPF, DKIM, and DMARC records, simplifying email authentication and allowing experimentation without affecting core business communications. A proper SPF setup requires consideration of the return path, necessitating dedicated SPF records and MX records for each ESP when multiple ESPs are in use. Delegation to a subdomain also facilitates easier tracking and adjustments to email authentication.
Key findings
- Reputation Shielding: Subdomains isolate the impact of marketing campaigns, safeguarding the primary domain's reputation from deliverability problems.
- Authentication Alignment: SPF should be aligned with the domain in the 5321.from address and EHLO, not the root domain.
- Independent Management of Records: Subdomains allow for independent management of SPF, DKIM, and DMARC records, improving email authentication control.
- Simplified Tracking: Delegating to a subdomain facilitates easier tracking and modifications to email authentication processes.
- Testing Capabilities: Subdomains offer a testing ground for new email strategies without impacting the primary domain's reputation.
Key considerations
- Return Path Configuration: Ensure the return path is properly configured and matches the email's source, with corresponding SPF and MX records.
- Multiple ESP Management: When using multiple ESPs, each requires a dedicated SPF domain for accurate authentication.
- DMARC Compliance: Employing subdomains aids in DMARC compliance by ensuring the correct alignment of SPF and DKIM with the 'From' domain.
- Implementation Complexity: While beneficial, implementing subdomains adds complexity to DNS management; careful configuration is vital.
What email marketers say
9 marketer opinions
Email marketers generally recommend using a subdomain for email marketing, particularly for SPF records. This practice isolates marketing emails from transactional or corporate emails, safeguarding the primary domain's reputation. Subdomains allow independent management of SPF, DKIM, and DMARC records, facilitate experimentation with new email strategies, and simplify the segmentation and tracking of email performance. If multiple email sending services are used, setting up SPF records for each subdomain is recommended. Subdomains also enable easier testing, troubleshooting deliverability issues, and switching email platforms without affecting the primary domain's email setup.
Key opinions
- Reputation Isolation: Using a subdomain protects the primary domain's reputation from deliverability issues caused by marketing campaigns.
- Independent Management: Subdomains allow for independent management of SPF, DKIM, and DMARC records, providing greater control over email authentication.
- Experimentation: Subdomains enable experimentation with new email strategies and platforms without impacting the primary domain.
- Segmentation & Tracking: Subdomains simplify the segmentation and tracking of email performance, allowing for better analysis and optimization.
- Testing and Troubleshooting: Subdomains provide easier testing and troubleshooting of email deliverability issues.
Key considerations
- Multiple Services: If using multiple email sending services, set up SPF records for each subdomain used by these services to ensure proper authentication.
- High Volume Sending: Using a separate subdomain is particularly important when sending high volumes of marketing emails due to the increased risk of deliverability issues.
- SPF, DKIM, DMARC Configuration: Ensure distinct SPF, DKIM, and DMARC records are configured for the subdomain to manage its reputation independently.
Marketer view
Email marketer from Sendinblue explains that setting up a dedicated subdomain, such as email.yourdomain.com, is a best practice for email marketing. This isolates your sender reputation, and allows you to manage the SPF, DKIM, and DMARC records independently from your main domain. It protects your primary domain's reputation from potential deliverability issues with marketing campaigns.
4 Mar 2023 - Sendinblue
Marketer view
Email marketer from Email Deliverability Community suggests that using a subdomain allows for easier testing and troubleshooting of email deliverability issues. This user also mentions that if you change email marketing platforms or strategies, it's easier to make changes on a subdomain without affecting the primary domain's email setup.
16 Mar 2025 - Email Deliverability Community
What the experts say
6 expert opinions
Experts recommend using subdomains for SPF records in email marketing to protect the primary domain's reputation. It is not best practice to set up SPF for an ESP at the root domain. The SPF record should correspond to the domain used in the 5321.from address and, in some cases, the EHLO. A subdomain isolates any deliverability issues, allowing the primary domain to maintain a clean sending reputation, particularly for transactional emails. Proper SPF setup involves considering the return path, which should match the source of the email and have corresponding SPF records and MX records. If multiple ESPs are used, a dedicated SPF domain is needed for each. Delegating to a subdomain facilitates easier tracking and adjustments to email authentication, managing marketing sends separately from transactional or corporate mail.
Key opinions
- Reputation Protection: Subdomains safeguard the primary domain's reputation by isolating deliverability issues from marketing campaigns.
- SPF Placement: SPF should not be set up at the root domain for ESPs but should correspond to the domain in the 5321.from address and EHLO.
- Return Path Importance: The return path determines where bounces go and requires corresponding SPF records; each ESP needs its own SPF domain.
- Easier Tracking: Delegating to a subdomain allows easier tracking and adjustments to email authentication.
Key considerations
- Return Path Alignment: Ensure the return path is aligned with the sending source and has the correct SPF records and MX records.
- Multiple ESPs: If using multiple ESPs, set up a dedicated SPF domain for each to maintain proper email authentication.
- CNAME vs TXT: Consider using CNAME records for SPF if possible, but a TXT record with 'include' is also acceptable.
Expert view
Expert from Email Geeks shares an example: if you’re customer.com and the ESP is esp.com and your return path is pineapple.customer.com then the ESP should have a TXT record at something like spf.esp.com, and you should either have a TXT record at pineapple.customer.com that has “include:spf.esp.com” or, more commonly, pineapple.customer.com should be a CNAME to spf.esp.com. Also mentions that If your return path is something like iguana.esp.com then you can’t publish SPF for that mail stream, only your ESP can, and it won’t be aligned.
26 Oct 2024 - Email Geeks
Expert view
Expert from Word to the Wise explains that delegating to a subdomain allows for easier tracking and adjustments to email authentication. It means you can manage the reputation of your marketing sends separately from the reputation of your transactional or corporate mail streams.
22 Mar 2022 - Word to the Wise
What the documentation says
5 technical articles
Documentation from various sources including Google, Microsoft, DMARC.org, RFC Editor, and AWS recommends using subdomains for SPF records in email marketing, especially when dealing with multiple email service providers or sending systems. This practice simplifies SPF and DKIM management, isolates sending reputation, allows specific SPF settings for each email stream, makes management and troubleshooting easier, and can help prevent deliverability issues, including email delivery failures due to incorrect SPF configurations. Proper alignment of SPF and DKIM records with the 'From' address domain is emphasized for DMARC compliance.
Key findings
- Simplified Management: Subdomains simplify the management of SPF and DKIM records, particularly for organizations with multiple email streams.
- Isolated Reputation: Using a dedicated subdomain isolates the sending reputation of marketing or transactional emails, preventing deliverability issues from affecting core communications.
- Specific SPF Settings: Dedicated subdomains allow for specific SPF settings for each email stream, aiding in managing and troubleshooting deliverability issues.
- DMARC Compliance: Subdomains make it easier to ensure proper alignment of SPF and DKIM records with the domain used in the 'From' address, which is essential for DMARC compliance.
Key considerations
- Multiple Senders: If sending email from different systems or using multiple email service providers, configuring SPF records for each subdomain is important.
- Configuration Accuracy: Incorrect SPF configuration can lead to email delivery failures, so careful setup is crucial.
- Google Recommendation: Google recommends configuring SPF records for any domain or subdomain that sends email.
Technical article
Documentation from AWS explains that when using Amazon SES for sending emails, it is recommended to set up SPF and DKIM records for a dedicated subdomain. This isolates the sending reputation of your marketing or transactional emails from your primary domain, preventing deliverability issues from affecting your core business communications.
2 Dec 2024 - Amazon Web Services
Technical article
Documentation from DMARC.org explains that while not strictly required, using subdomains can simplify SPF and DKIM management, especially for organizations with multiple email streams. They highlight that proper alignment of SPF and DKIM records with the domain used in the 'From' address is essential for DMARC compliance, and subdomains can make this easier to manage.
9 Dec 2023 - DMARC.org
Can DKIM be set up on a subdomain, and which domain should be used for signing?
Do I need to set up DMARC for subdomains?
How can I optimize my SPF record to stay within the lookup limit when using multiple email sending services?
How do I properly set up SPF and DKIM records for email marketing, including handling multiple SPF records, IP ranges, bounce capturing, and Google Postmaster Tools verification?
How do I set up SPF and DKIM records for new subdomains when using third-party email services?
Why does SPF alignment show as 0% on Validity, even when SPF passes?
