Summary
The provided information indicates that while BIMI settings can be inherited from a parent domain to its subdomains, it is not a mandatory requirement. A subdomain can independently implement BIMI as long as it meets the DMARC requirements (policy set to 'quarantine' or 'reject') and has a DNS record pointing to the brand's logo. The BIMI selector, although available, is not widely used, with most systems recognizing only the default selector. Therefore, the critical factor is the subdomain's DMARC compliance, enabling it to function independently of the parent domain's BIMI configuration.
Key findings
- Independent BIMI Implementation: Subdomains can implement BIMI independently if they meet the DMARC requirements, even without the parent domain having a BIMI record.
- DMARC Compliance is Key: DMARC compliance (policy set to 'quarantine' or 'reject') is a prerequisite for subdomains to leverage BIMI.
- Optional Inheritance: BIMI settings can be inherited from the parent domain if the subdomain meets the DMARC requirements, but it's not a necessity.
- Selector Usage Limited: Most systems primarily recognize the default BIMI selector.
Key considerations
- Prioritize DMARC: Ensure the subdomain's DMARC policy is correctly configured and enforced (set to 'quarantine' or 'reject').
- DNS Record Setup: Create a DNS record pointing to the brand's logo file for the subdomain.
- Selector Implementation: While non-default selectors exist, using the default selector ensures broader compatibility.
- BIMI Selector Header: BIMI-Selector header can be implemented on outbound mail.
What email marketers say
7 marketer opinions
The consensus is that a parent domain does not necessarily need a BIMI record for a subdomain to implement BIMI. The crucial factor is that the subdomain must independently meet the DMARC requirements. While BIMI inheritance from a parent domain is possible, it's not a prerequisite, and subdomains can function independently if their DMARC policy is properly configured. Selectors are available but not widely adopted. BIMI builds upon existing authentication standards.
Key opinions
- DMARC Dependency: Subdomains must meet DMARC requirements independently to implement BIMI, regardless of the parent domain's BIMI status.
- Independent BIMI: A subdomain can have BIMI even if the parent domain doesn't, given it adheres to DMARC.
- Selector Use: While BIMI selectors exist, most systems currently only recognize the default selector.
- BIMI inheritance: A subdomain can inherit from the organizational domain, but a sub-subdomain cannot inherit from a subdomain.
Key considerations
- DMARC Configuration: Ensure the subdomain's DMARC policy is correctly configured to either 'quarantine' or 'reject' to comply with BIMI requirements.
- BIMI Selector: Use the default BIMI selector `default._bimi.domain.com` for maximum compatibility across email systems.
- DNS Record: A DNS record must point to your logo file.
Marketer view
Marketer from Email Geeks mentions that it is analogous to DKIM. The only non-default selector seen so far is `smile._<http://bimi.amazon.com|bimi.amazon.com>`.
24 Dec 2023 - Email Geeks
Marketer view
Email marketer from Stack Overflow answers that it is possible to have BIMI on a subdomain, even if the parent domain does not have it, as long as the subdomain meets the DMARC requirements.
30 May 2023 - Stack Overflow
What the experts say
4 expert opinions
The responses indicate that while BIMI can be inherited from an organizational domain to subdomains, it's not a requirement for the subdomain to function. A subdomain can independently implement BIMI if it meets DMARC requirements and sets up the necessary DNS record pointing to the logo file. Experts confirm that a parent domain does not explicitly need a BIMI record for a subdomain to successfully use BIMI.
Key opinions
- BIMI Inheritance: BIMI settings from the organizational domain can be inherited by subdomains.
- Independent Subdomain BIMI: A subdomain can implement BIMI independently of the parent domain.
- DMARC Requirement: Meeting DMARC requirements is essential for a subdomain to implement BIMI.
- DNS Setup: Setting up a DNS record pointing to the logo file is a key step in BIMI implementation for subdomains.
Key considerations
- DMARC Compliance: Verify that the subdomain meets DMARC requirements to ensure BIMI functionality.
- DNS Configuration: Properly configure the DNS record to point to the correct logo file location.
- Optional Inheritance: While inheritance from the organizational domain is possible, it is not a mandatory setup.
Expert view
Expert from Email Geeks confirms that BIMI can be set up only on the subdomain if desired.
24 Dec 2024 - Email Geeks
Expert view
Expert from Word to the Wise explains that BIMI involves setting up a DNS record with a pointer to your logo file. As long as the subdomain meets the DMARC and other BIMI requirements, the parent domain does not explicitly need to have a BIMI record.
4 Feb 2024 - Word to the Wise
What the documentation says
3 technical articles
The documentation indicates that BIMI is configured at the domain level, allowing subdomains to inherit BIMI settings from the parent domain if they meet the necessary DMARC requirements. While a parent domain's BIMI configuration isn't a strict dependency for a subdomain to function with BIMI, the subdomain's DMARC policy ('quarantine' or 'reject') is crucial. The BIMI-Selector header can be inserted on outbound mail.
Key findings
- Domain-Level Configuration: BIMI is primarily configured at the domain level.
- DMARC Requirement: A subdomain must have a DMARC policy set to 'quarantine' or 'reject' to leverage BIMI.
- Inheritance: Subdomains can inherit BIMI settings from the parent domain if DMARC requirements are met.
- BIMI-Selector Header: The BIMI-Selector header can be inserted in outbound emails.
Key considerations
- DMARC Policy: Ensure the subdomain's DMARC policy is set to 'quarantine' or 'reject'.
- Inheritance vs. Independent Setup: Decide whether to inherit BIMI settings from the parent domain or configure BIMI independently for the subdomain.
- BIMI-Selector Header: Explore the usage of BIMI-Selector header
Technical article
Documentation from BIMI Group explains that BIMI is configured at the domain level. If you implement BIMI on your main domain, it can be inherited by subdomains if the subdomain's DMARC policy meets the BIMI requirements. The subdomain itself doesn't need a separate BIMI record if inheriting from the parent.
11 Mar 2024 - BIMI Group
Technical article
Documentation from IETF mentions how the the BIMI-Selector header as one that the sender can insert on outbound mail.
7 Mar 2024 - datatracker.ietf.org
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