Experts, marketers, and documentation consistently recommend using subdomains to separate promotional and transactional emails when on a shared IP. This isolates sender reputation, protecting critical transactional emails from deliverability issues potentially caused by promotional campaigns. The approach enables granular control through separate SPF and DKIM configurations, simplifies issue monitoring, and is considered a best practice for maintaining a healthy email infrastructure on shared IPs.
11 marketer opinions
The consensus is that using subdomains to separate promotional and transactional emails on a shared IP is highly recommended. This practice isolates sender reputation, preventing deliverability issues with promotional emails from negatively impacting the delivery of critical transactional emails. Subdomain separation also enables individual monitoring of email streams for better issue detection and resolution.
Marketer view
Email marketer from Litmus responds that it's crucial to separate email streams using subdomains when on a shared IP. This approach helps to manage sender reputation and ensures that transactional emails, which are vital for user experience, aren't affected by any deliverability issues with promotional emails.
23 Jun 2023 - Litmus
Marketer view
Email marketer from GMass explains that employing subdomains can help improve deliverability on shared IPs. By separating promotional and transactional emails, you prevent the negative reputation from promotional emails affecting transactional emails. If there are any deliverability problems, they stay isolated to a smaller subdomain.
11 Oct 2021 - GMass
3 expert opinions
Experts generally agree that using subdomains to separate promotional and transactional emails on a shared IP is a best practice. This helps isolate reputation issues stemming from potentially problematic promotional campaigns, protecting the deliverability of critical transactional emails. The use of subdomains also allows for better management and segregation of different email streams, especially vital given the impact of other senders on a shared IP address.
Expert view
Expert from Word to the Wise, Laura Atkins, responds that when using a shared IP, it's beneficial to separate different mail streams via subdomains. Since others are using the same IP, their sending practices can impact your deliverability. By segregating promotional and transactional emails, you mitigate the risk of poor promotional mail practices affecting your transactional email delivery. It mentions that reputation is per domain, and subdomains can help manage this.
1 Dec 2022 - Word to the Wise
Expert view
Expert from Email Geeks explains using a subdomain for the d= of the DKIM signature is a good practice, especially if promotional emails might cause deliverability problems. They suggest using separate subdomains for transactional (e.g., trans.whatever) and promotional emails (e.g., promo.whatever), reserving the root domain for corporate mail. This is Laura's preferred way of managing email domains.
1 Oct 2023 - Email Geeks
5 technical articles
Technical documentation consistently recommends using subdomains to separate promotional and transactional emails, especially on shared IPs. This approach enables distinct SPF and DKIM configurations for each subdomain, providing granular control over email authentication and sender reputation. Isolating email types in this manner helps protect the deliverability of critical transactional emails by preventing issues with promotional sends from negatively affecting the main domain.
Technical article
Documentation from RFC states DKIM signatures can be applied using different subdomains in the 'd=' tag. This practice allows for granular control over email authentication and helps to isolate the reputation of different email streams, which is especially useful with shared IPs.
6 Oct 2023 - RFC 6376
Technical article
Documentation from SparkPost shares using subdomains for different email streams (transactional, marketing) allows you to configure separate sender authentication (SPF, DKIM) for each. This level of control is beneficial when on shared IPs, as it allows you to fine-tune your deliverability strategy for each type of email.
30 Oct 2021 - SparkPost
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