Summary
Configuring DNS records to send emails from two different Email Service Providers (ESPs) using the same subdomain is a common challenge for organizations seeking to maintain brand consistency and streamline email operations. While technically feasible, this setup introduces significant complexities, particularly concerning SPF, DKIM, and MX records. It often requires a deep understanding of email authentication protocols and careful coordination across multiple systems. Although it offers the benefit of a unified sending identity, it can lead to increased management overhead and potential deliverability issues if not implemented precisely.
Key findings
- SPF record complexity: Combining SPF records for multiple ESPs into a single record is possible but must adhere to the 10 DNS lookup limit to remain valid. Having multiple SPF records is not supported and will invalidate all of them.
- DKIM flexibility: Multiple DKIM records do not interfere with each other. Different selectors can easily be used for each ESP.
- MX record challenges: If the subdomain's MX record already points to an internal service desk for replies, the ESP might not be able to collect and suppress bounces, impacting deliverability and reporting accuracy.
- Dedicated subdomains: Many experts and ESPs advise using a dedicated subdomain for each mail stream to simplify management and mitigate potential deliverability risks, even if sharing is technically possible.
Key considerations
- Impact on deliverability: Improper configuration can lead to authentication failures (SPF, DKIM, DMARC), resulting in emails being blocked or sent to spam folders. This can significantly affect your email deliverability.
- DMARC reporting: Sharing a subdomain adds layers of complexity to analyzing DMARC reports, making it harder to diagnose issues and optimize performance for individual sending streams.
- ESP support: Many ESPs recommend delegating DNS management to them precisely because of these complexities, and they may offer limited support for custom, self-hosted DNS configurations.
- Technical expertise required: Successfully implementing such a setup demands a thorough understanding of DNS, email authentication protocols like SPF, DKIM, and DMARC, and the specific requirements of each ESP. This can be complex, and some tools like Kitterman's SPF validator can help with SPF syntax.
What email marketers say
Email marketers often face the challenge of reconciling branding needs with technical email sending requirements, especially when multiple ESPs are involved. The desire to maintain a consistent brand identity by sending from a primary domain or subdomain frequently runs up against the complexities of DNS configuration. While some marketers recognize the simplicity of dedicated subdomains for different mail streams, others express a strong preference or business need to use a single, familiar subdomain, even if it introduces technical hurdles.
Key opinions
- Branding priority: Marketers frequently prioritize brand consistency, desiring to send all emails from a single, recognizable subdomain, regardless of the ESP used.
- Belief in possibility: There's a common sentiment that if other CRM systems can send on behalf of a primary domain, then marketing clouds should also offer similar flexibility.
- Confusion with ESP advice: Marketers can become confused when ESPs advise against sharing subdomains, especially when they've successfully configured dedicated subdomains for other purposes in the past.
- Seeking workarounds: When faced with restrictions, marketers look for ways to implement a dual or triple DNS setup to achieve their desired sending configuration.
Key considerations
- Business justification: The decision to use a shared subdomain should be weighed against the technical complexities and potential impact on deliverability and sender reputation. Consider if it is necessary to use the same sending domain with multiple ESPs.
- ESP limitations: Some ESPs (like Marketing Cloud) have policies that encourage DNS delegation, making self-hosting a shared subdomain a use at your own risk scenario.
- Deliverability sacrifices: Custom, complex setups may force compromises that impact optimal email deliverability or make troubleshooting more difficult. Understanding how to troubleshoot SPF authentication issues is crucial.
- Operational complexity: Managing a shared subdomain for multiple mail streams can complicate ongoing maintenance, support, and the overall understanding of email flow.
Marketer view
An email marketer from Email Geeks conveyed a sense of confusion regarding the feasibility of configuring DNS for two ESPs on one subdomain, especially when ESPs are reluctant to provide detailed guidance or documentation. They felt that if Salesforce CRM could send on behalf of Gmail, then Salesforce Marketing Cloud should also have a viable configuration option.
Marketer view
A marketer from Email Geeks explained that they have advised clients for years to use separate subdomains for Marketing Cloud, arguing it's a simpler setup and that automated emails should not appear to come from a human address. However, they acknowledged that if a client insists on using the same subdomain, and if platforms like Pardot natively support it, Marketing Cloud should also offer a solution.
What the experts say
Email deliverability experts offer nuanced perspectives on configuring DNS for multiple ESPs on a single subdomain. While they acknowledge the technical possibility, they often caution against it due to the complexities and potential impact on deliverability and reporting. Key areas of concern include SPF record limitations, proper MX record setup for bounce handling, and the intricacies of DMARC reporting when managing shared sending identities.
Key opinions
- SPF rule: It is strongly advised that each ESP should have its own 5321.from domain with a unique SPF TXT record, rather than attempting to share one SPF record across multiple ESPs.
- MX for bounces: Each 5321.from domain should also have its own MX record specifically for bounce handling, ensuring that bounces are properly returned to the correct sending system.
- DKIM selectors: Configuring DKIM for multiple ESPs is relatively straightforward by simply using different selectors for each ESP's record.
- Delegation preference: Most ESPs recommend letting them handle domain delegation because it simplifies the DNS configuration and removes the burden of complex setup from the sender.
Key considerations
- Hidden complexities: While technically achievable, shared subdomain setups can be highly complex and are generally advised against due to the difficulties in management and potential for deliverability issues.
- DMARC reporting challenges: An additional layer of complexity is introduced when analyzing DMARC reports for mail streams sharing a subdomain, making it harder to pinpoint sources of authentication failures or abuse. Utilize DMARC reports from Google and Yahoo to mitigate this.
- Specificity of advice: Providing precise DNS configuration advice for shared subdomains is impossible in the abstract; it requires examining specific email examples and understanding each CRM or ESP's unique setup. This is why best practices for DNS lookups are important.
- SPF validation: SPF primarily validates the 5321.from (Return-Path) address, not necessarily the 5322.from (From) address visible to the recipient. This distinction is vital for proper authentication.
Expert view
An expert from Email Geeks states that SPF records can be consolidated into a single entry, provided the combined record does not exceed the 10 DNS lookup limit. They cautioned that deploying two separate SPF record entries would render both invalid, emphasizing the need for proper syntax when joining them.
Expert view
An expert from Email Geeks clarified that having multiple DKIM records does not present a problem and they do not interfere with each other. This means different DKIM selectors can be used effectively for various sending systems.
What the documentation says
Official documentation from various DNS providers and email standards organizations outlines the foundational requirements for email sending, including the role of different DNS record types. It typically emphasizes the need for distinct records for subdomains and often highlights how different authentication protocols, like DKIM, use selectors to manage multiple keys for the same domain. Understanding these guidelines is crucial for any advanced DNS configuration.
Key findings
- DNS record types: To send and receive emails, documentation consistently points to the necessity of setting up MX, SPF (TXT), and DKIM (TXT or CNAME) records.
- Subdomain specific records: Each subdomain used for email sending typically requires its own set of DNS records, distinct from the root domain, to ensure proper authentication and routing. This is vital when considering how to set up email subdomains.
- DKIM selectors: Documentation confirms that DKIM (and sometimes BIMI) supports selectors, which enable multiple distinct records to be published for the same domain, allowing for different signing keys per ESP or mail stream.
- NS records for subdomains: For custom MAIL FROM subdomains, NS records might be required to delegate authority to a specific DNS server for that subdomain, as indicated by some cloud provider documentation. When adding an MX record to a subdomain, it can be tricky if CNAMEs are used for email sending verification.
Key considerations
- Adherence to standards: Following RFC standards for DNS and email authentication is paramount to ensuring optimal deliverability across all recipients.
- ESP-specific requirements: While general principles apply, each ESP will have specific DNS records (e.g., CNAMEs for tracking, unique DKIM keys) that need to be configured for their service.
- Self-hosting vs. delegation: Documentation often implies that delegating DNS to the ESP simplifies setup, avoiding the complexities of manual DNS management and potential misconfigurations. For example, the Cloudflare DNS documentation can provide more information on how to add email records.
- Comprehensive setup: A complete email sending setup involves not just SPF and DKIM, but also MX records for mail exchange and DMARC for policy enforcement and reporting.
Technical article
Cloudflare DNS documentation states that to send and receive emails from your domain, you need an SMTP provider. It also details the steps for creating specific DNS records, such as MX, SPF, and DKIM entries, within their platform to ensure proper email functionality.
Technical article
The BIMI Group FAQs clarify that, similar to DKIM, BIMI (Brand Indicators for Message Identification) also supports selectors. This feature allows a single domain to publish multiple, distinct BIMI records, providing flexibility for different email streams or brand representations.
Related resources
12 resources
Related pages
How to set up email authentication for multiple ESPs on the same sending domain?
Does a subdomain used for sending emails need its own SPF record?
How do I set up an SPF record when using multiple email sending services?
Is it possible to point one subdomain to multiple email service providers?
What are the implications of sharing a subdomain between two different ESPs?
A simple guide to DMARC, SPF, and DKIM
A list of the most common DKIM selectors and how to use them
Understanding and troubleshooting DMARC reports from Google and Yahoo
How to set up email subdomains and what DNS records are required?
How do I ensure email deliverability with different return-path addresses and subdomains?
