Summary
When managing email deliverability, a common question arises regarding Google Postmaster Tools and whether all sending subdomains require individual addition. The consensus from experts and documentation is a resounding yes, primarily because Google (and other mailbox providers) treat subdomains as distinct entities with their own sender reputations. This granular approach ensures you have a clear, isolated view of performance metrics for each sending stream, which is crucial for identifying and addressing issues quickly. Ignoring subdomains can lead to blind spots in your deliverability monitoring.
Key findings
- Separate reputations: Subdomains maintain their own distinct sender reputation in Google Postmaster Tools, separate from the root domain. This means issues on one subdomain might not directly impact another, but if left unmonitored, could escalate.
- Comprehensive data: Adding all subdomains provides a complete picture of your sending performance across all email streams, which is essential for proactive deliverability management. You can learn more about this in our guide on understanding Google Postmaster Tools.
- Authentication alignment: Google Postmaster Tools groups data based on the SPF or DKIM authenticating domain. Therefore, you should add all subdomains used for authentication purposes.
- Granular insights: Segmenting your traffic by adding individual subdomains allows for more precise monitoring and troubleshooting of deliverability issues.
Key considerations
- Discovery of subdomains: If you are unsure which subdomains you are sending from, DMARC aggregate reports can help identify them. Our DMARC monitoring platform can assist with this.
- Verification process: Each subdomain (or root domain) needs to be verified individually in Google Postmaster Tools by adding a TXT record to its DNS. For detailed steps, refer to this guide on setting up Postmaster Tools.
- New sender requirements: With recent changes from Google and Yahoo, maintaining good sender reputation across all sending domains and subdomains is more critical than ever.
- Impact on root domain: While subdomains have separate reputations, severe issues on a subdomain can still negatively affect the overall brand reputation associated with the root domain.
What email marketers say
Email marketers often debate the necessity of adding every subdomain to Google Postmaster Tools. The general sentiment among marketers is that it is a best practice, if not an absolute requirement, for effective deliverability monitoring. Many emphasize that each subdomain (or sending domain) often carries its own reputation, and understanding these individual metrics is key to optimizing email programs and avoiding blocklists.
Key opinions
- Individual tracking: Marketers frequently express the need for individual subdomain tracking to pinpoint deliverability issues more accurately.
- Reputation isolation: The belief is that subdomains have largely independent reputations, making individual monitoring essential to prevent cross-contamination of bad sender scores.
- Proactive management: Many marketers use Postmaster Tools to proactively manage their sender reputation, noting that adding subdomains helps them react faster to dips in performance.
Key considerations
- Sender segmentation: If you segment your email traffic across multiple subdomains (e.g., transactional, marketing, promotional), adding each one allows for specific performance insights.
- Monitoring requirements: Consider your team's capacity to monitor multiple Postmaster Tools dashboards. While beneficial, it does add to the workload.
- Risk mitigation: Adding all subdomains helps mitigate risks. If one subdomain gets blocklisted, it might not bring down the entire root domain, though overall brand perception can suffer. Read our guide on what happens when your domain is blocklisted.
- Data completeness: To get a truly complete view of all your sending domains, you should include all subdomains.
Marketer view
Marketer from Email Geeks notes that they struggle to track all their subdomains for sending, indicating a common challenge for many email marketers trying to monitor deliverability.
Marketer view
Marketer from Kickbox Blog suggests that adding each subdomain to Postmaster Tools is a good strategy. This is particularly important for obtaining detailed insights into distinct sender reputations across various traffic segments.
What the experts say
Email deliverability experts consistently advise adding all subdomains to Google Postmaster Tools. Their reasoning centers on the fundamental principle that each subdomain operates with its own distinct reputation within the Google ecosystem. This separation necessitates individual monitoring to accurately diagnose deliverability issues, prevent blanket blacklistings, and ensure optimal inbox placement across all email sending streams.
Key opinions
- Mandatory addition: Experts confirm that you must add each subdomain to Postmaster Tools for proper monitoring.
- Separate reputations: Subdomains and root domains maintain separate reputations, making individual tracking crucial to avoid overall domain reputation damage.
- Authentication as key: Postmaster Tools groups data by the SPF or DKIM authenticating domain, so all subdomains used for authentication should be added. This is especially relevant for DMARC authentication.
- Data accuracy: Adding all relevant subdomains ensures the most accurate and complete data for deliverability analysis.
Key considerations
- DMARC data for discovery: DMARC data is highly effective for identifying all active sending subdomains. This is a critical first step if you're unsure which subdomains to add.
- Sender reputation management: Maintaining a healthy sender reputation for each subdomain is vital for consistent inbox placement. Learn how to improve your domain reputation.
- Verification process: Each subdomain needs its own verification, even if the main domain is already verified. This is detailed in Mailgun's guide to sender reputation.
- Monitoring resources: Ensure you have the tools and resources to monitor the distinct data points for each added subdomain effectively.
Expert view
Expert from Email Geeks confirms that it is necessary to add each subdomain individually to Google Postmaster Tools for comprehensive tracking. This ensures that all sending domains are properly monitored.
Expert view
Expert from Word to the Wise emphasizes the critical role of understanding domain reputation for email deliverability. They often discuss how different sending streams, including subdomains, contribute to this reputation.
What the documentation says
Official documentation and technical guides from Google and other authoritative sources generally support the practice of adding subdomains to Postmaster Tools. This is because email ecosystems, particularly major mailbox providers like Gmail, assess sender reputation at a granular level, often down to the subdomain. Therefore, to gain complete visibility and accurate insights into your email program's performance, individual subdomain registration is recommended to track their specific reputations and deliverability metrics.
Key findings
- Granular reputation tracking: Documentation confirms that Postmaster Tools tracks reputation at the subdomain level, providing distinct data for each sending entity.
- Verification process: Each subdomain requires a separate TXT record for verification in Google Postmaster Tools, reinforcing the need for individual setup.
- Aligned domains: Postmaster Tools uses the SPF or DKIM authenticating domain to group data, meaning any subdomain used for authentication should be added.
- Comprehensive insights: To gain a holistic view of your sender reputation, all active subdomains should be registered and monitored. For more, see our article on how Postmaster Tools handles subdomains.
Key considerations
- Automated data collection: Once verified, Postmaster Tools automatically collects data for the added domains and subdomains, providing ongoing insights into performance.
- Domain ownership: You must prove ownership of each domain or subdomain by adding a TXT record to its DNS before data becomes available. This is covered in EmailSherpa's setup guide.
- Timeliness of data: It takes time for Postmaster Tools to accumulate sufficient data, especially for new sending subdomains. Consistency in sending helps data populate faster.
- Debugging deliverability: Separate subdomain data helps in debugging specific deliverability issues, such as spam complaints or blocklist entries, enabling targeted remediation efforts.
Technical article
Documentation from Email Industries states that if you use subdomains for sending email, it is recommended to simply add your root domain. This implies that for some basic monitoring, the root domain might suffice, though granular data would be lost.
Technical article
Documentation from Mailgun recommends adding each subdomain to Google Postmaster Tools separately if you segment your traffic. This strategy ensures you retain distinct data points for each segment, aiding in reputation management.
Related resources
10 resources
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