Documentation

NAME

Mail::MIMEDefang::BIMI - Brand Indicators for Message Identification support for MIMEDefang

DESCRIPTION

Mail::MIMEDefang::BIMI provides methods to look up and verify BIMI DNS records from mimedefang-filter. BIMI (Brand Indicators for Message Identification) allows domain owners to publish a verified logo that mail clients can display alongside authenticated messages.

A BIMI record is only considered valid when the sending domain passes DMARC at enforcement level (p=quarantine or p=reject).

When the Mail::BIMI Perl module (version 3.x or later) is installed, md_bimi_lookup and md_bimi_verify use it for richer validation, including SVG logo integrity and Verified Mark Certificate (VMC) chain verification. Without Mail::BIMI the checks are limited to DNS record existence and a non-empty l= tag.

METHODS

  • md_init

    Detect and load Mail::BIMI if installed, setting $Features{"Mail::BIMI"}. Called automatically by detect_and_load_perl_modules in Mail::MIMEDefang.

  • md_bimi_get_selector($entity)

    Extract the BIMI selector from the BIMI-Selector header of a MIME::Entity object. The header format is:

    BIMI-Selector: v=BIMI1; s=brand1;

    Returns the selector string (e.g. "brand1") on success, or "default" when the header is absent, malformed, or $entity is undefined.

    Typical usage in filter_begin($entity):

    my $selector = md_bimi_get_selector($entity);
my $result   = md_bimi_verify($domain, $dmarc_result, $policy, $selector);

  • md_bimi_lookup($domain [, $selector])

    Look up the BIMI DNS TXT record for $domain.

    The optional $selector argument specifies which BIMI selector to query (e.g. "brand1" → brand1._bimi.$domain). When omitted or undef, "default" is used. Use md_bimi_get_selector to derive the selector from the message's BIMI-Selector header.

    Returns a hashref with the following keys on success:

    • version

      Always BIMI1.

    • l

      The URL of the SVG logo (l= tag).

    • a

      The URL of the Verified Mark Certificate (a= tag), if present.

    • raw

      The raw TXT record string.

    Returns undef if no BIMI record is found or if Net::DNS is not available.

  • md_bimi_verify($domain, $dmarc_result, $dmarc_policy [, $selector])

    Verify that a domain's BIMI record is valid given the DMARC result.

    BIMI is only considered to pass when:

    • A BIMI DNS record exists for $domain.
    • $dmarc_result is pass.
    • $dmarc_policy is quarantine or reject (enforcement level).
    • The BIMI record contains a non-empty l= (logo URL) tag.

    Returns "pass" on success, "fail" otherwise.

    The method accepts the following parameters:

    • $domain

      The sender's domain (From: header domain).

    • $dmarc_result

      The DMARC result string, e.g. "pass" or "fail".

    • $dmarc_policy

      The DMARC policy in effect: "none", "quarantine", or "reject".

    • $selector

      Optional BIMI selector string. Defaults to "default". Pass the value returned by md_bimi_get_selector($entity) to honour the message's BIMI-Selector header.