Does BIMI trickle down to subdomains and how to control subdomain BIMI display?
Summary
What email marketers say7Marketer opinions
Email marketer from Mailhardener.com explains the hierarchical nature of DMARC and its effect on BIMI. Subdomains inherit the DMARC policy of the main domain unless overridden. Therefore, BIMI's effect on subdomains is tied to the DMARC policy in place. To disable BIMI on subdomains, setting a specific DMARC record is necessary.
Email marketer from EmailToolTester.com explains that subdomains need a DMARC policy of 'reject' or 'quarantine' for BIMI to work correctly. If a subdomain uses 'none' or lacks a DMARC record, BIMI may not display.
Email marketer from Gmass.co explains that the best way to ensure BIMI displays correctly on subdomains is to create specific DMARC records on each subdomain. This overrides and enables control of BIMI on each subdomain.
Email marketer from StackOverflow suggests that to prevent a subdomain from displaying a BIMI logo, you can set the BIMI record on that specific subdomain to an empty or non-functional BIMI record (e.g., `v=BIMI1;`). This overrides the parent domain's BIMI setting.
Marketer from Email Geeks shares a method to prevent BIMI logos from showing on subdomains. Setting the BIMI record to `v=BIMI1;` will disable the logo display for that subdomain.
Email marketer from LinkedIn recommends implementing a specific DMARC policy for each subdomain if you want granular control over BIMI. This ensures that only intended subdomains display the BIMI logo.
Email marketer from Reddit states that for BIMI to work on a subdomain, the subdomain needs a valid DMARC record aligned with the sending domain. If the subdomain doesn't have a DMARC record or the alignment fails, BIMI won't be displayed.
What the experts say3Expert opinions
Expert from Spam Resource explains that while DMARC policies are inherited by subdomains, controlling BIMI display requires specific DMARC records for each subdomain. A subdomain without a DMARC record will inherit the parent's policy, but to disable BIMI, the subdomain must have its own DMARC record.
Expert from Word to the Wise details how to manage BIMI in subdomains. Because BIMI relies on the DMARC policy to function correctly, to prevent a subdomain from using the top level domain's BIMI, a DMARC record must exist on each subdomain.
Expert from Email Geeks explains that for BIMI to work on subdomains, the subdomain needs to be compliant with DMARC at enforcement, meaning settings like `p=reject; sp=none` are not sufficient.
What the documentation says3Technical articles
Documentation from dmarc.org details how DMARC policies are inherited by subdomains. To control BIMI at the subdomain level, specific DMARC records need to be in place for the subdomain. If the subdomain has its own DMARC policy, it will dictate whether BIMI applies.
Documentation from Entrust.com clarifies that BIMI relies on a valid DMARC policy. Subdomains inherit DMARC policies, influencing BIMI display. Properly configured DMARC records at the subdomain level are necessary for BIMI to function correctly.
Documentation from DigiCert.com explains that BIMI, like DMARC, can apply to subdomains. The behavior depends on the DMARC policy set for the subdomain. If a subdomain has a DMARC policy that passes validation, the BIMI record at the top level can influence the subdomain's branding.