Summary
When your BIMI (Brand Indicators for Message Identification) DNS record returns an unexpected string like "73Gcymai" instead of the full, correct value, it indicates a fundamental misconfiguration within your DNS setup. This isn't a random occurrence; rather, it is often a symptom of underlying issues such as malformed TXT record syntax, the presence of conflicting DNS entries like wildcards, or CNAME records that violate DNS standards. Troubleshooting requires a methodical approach to inspect the entire DNS zone and verify adherence to both BIMI specifications and general DNS RFCs.
Key findings
- Unexpected string interpretation: The "random" string is typically an artifact of how a DNS resolver interprets a malformed or conflicting record, not a truly random value.
- Semicolon interference: An extra semicolon at the end of the BIMI record string, even if seen in some examples, can cause parsing failures for certain DNS systems.
- Wildcard record precedence: An existing wildcard DNS record (e.g., * TXT "value") can unintentionally override a specific BIMI TXT record, leading to the wildcard's value being returned.
- CNAME conflicts:A CNAME record at the same hostname as a BIMI TXT record creates a conflict that violates DNS standards (RFC 1912) and will prevent proper resolution.
- DNS provider specifics: Certain DNS providers might handle TXT record lengths or formatting differently, which can contribute to unexpected outcomes.
Key considerations
- Verify record syntax: Always double-check your BIMI TXT record against the official BIMI specification for precise formatting, including correct use of semicolons and URL structure.
- Audit for wildcards: Conduct a thorough inspection of your DNS zone file for any wildcard TXT records that could be unintentionally overriding your specific BIMI entry for subdomains.
- Check CNAME presence: Ensure there are no CNAME records set for the exact subdomain where your BIMI TXT record is published, as this will lead to a conflict.
- Utilize DNS lookup tools: Use tools like dig or nslookup to query your BIMI record directly and analyze the raw DNS response for clues.
- Consult provider documentation: Refer to your DNS hosting provider's documentation for any specific guidelines, quirks, or limitations regarding the publication and length of TXT records.
- Review authentication basics: A solid understanding of the basics of SPF, DKIM, and DMARC is crucial, as BIMI builds upon these authentication protocols.
What email marketers say
Email marketers frequently encounter unexpected behaviors when setting up DNS records, particularly for newer authentication standards like BIMI. Their practical experiences often highlight challenges such as the precise interpretation of documentation examples, the difficulty of debugging DNS configurations without direct administrative access, and the impact of seemingly minor syntax errors. These real-world issues underscore the delicate nature of DNS management in achieving proper email authentication.
Key opinions
- Debugging hurdles: Marketers often find it extremely challenging to diagnose DNS issues without direct access to the DNS management interface or specific tools.
- Syntax sensitivity: Even tiny deviations from the expected record syntax, such as an unintended semicolon or unclosed quote, can prevent proper DNS resolution.
- Confusion over "random" strings: The appearance of an unexpected, short string can be confusing, but marketers learn it usually indicates a DNS parsing error or an overriding record.
- Overlooked wildcard entries: Wildcard DNS records are a frequently forgotten or misunderstood element that can lead to unintended overrides of specific subdomain records.
- Documentation interpretation: Marketers heavily rely on examples from official and unofficial documentation, which can sometimes be misinterpreted or include characters that cause issues with specific DNS providers.
Key considerations
- Collaborate with IT: If you're an email marketer without direct DNS access, foster close collaboration with your IT or DNS administration team to ensure proper record inspection and modification.
- Test record syntax rigorously: Use online validators or simple command-line tools to test your record before and after publishing to catch subtle syntax errors.
- Understand DNS precedence: Familiarize yourself with how different DNS records, particularly wildcards and CNAMEs, interact and take precedence in resolution.
- Verify SVG URL and format: Ensure the URL for your BIMI logo (SVG file) is correctly formatted and publicly accessible, as issues with the image can also hinder BIMI display, even if the DNS record resolves.
- Cross-reference examples: Compare BIMI record examples from multiple reputable sources, not just one, to avoid misinterpretations that could lead to errors.
- Anticipate adoption challenges: Be prepared for the complexities inherent in BIMI adoption, which often include intricate DNS configurations. For more information, check this troubleshooting common BIMI issues article.
Marketer from Email Geeks observed that they were looking up some info on the BIMI record and thought the semicolon was part of it, but now realizes they might have been wrong. They still find it strange that it returns a random string, highlighting the confusion around unexpected DNS outputs.
Marketer from Email Geeks stated that they lacked access to their client's DNS tool, which prevented them from checking other configurations. This emphasizes a common barrier marketers face in diagnosing complex DNS issues.
What the experts say
Email deliverability experts agree that unexpected strings appearing in BIMI DNS records are not random occurrences. Instead, they are predictable outcomes of fundamental DNS configuration errors. Experts routinely point to common culprits such as unintended DNS wildcards, conflicting CNAME records, and the critical need for precise interpretation and implementation of DNS record syntax. Their insights are invaluable for diagnosing and resolving these complex issues.
Key opinions
- Not random: Experts consistently emphasize that the "random string" is a predictable symptom of a specific DNS misconfiguration, most commonly a wildcard record or CNAME conflict.
- Wildcard impact: Wildcard DNS records are a prevalent source of unexpected responses because they can inadvertently apply to subdomains where more specific records were intended.
- CNAME violations: The presence of a CNAME record at the same hostname as any other record type, including a TXT record for BIMI, is a violation of DNS standards and a frequent cause of resolution failures. For more on this, see how SPF resolution fails with CNAMEs.
- Syntax precision is key: DNS records, particularly TXT records carrying structured data like BIMI, demand exact adherence to their specified syntax rules; even minor errors can lead to parsing failures.
- DNS resolver behavior: While different DNS resolvers might handle malformed records with slight variations, they commonly default to displaying the first valid string found or an error-related output when an exact match isn't made.
Key considerations
- Thorough DNS zone audit: Conduct a comprehensive audit of the entire DNS zone to identify any hidden, conflicting, or overriding records, especially wildcards that might impact BIMI resolution.
- Understand RFC compliance: Be aware that DNS behavior, particularly issues like CNAME conflicts and TXT record formatting, is strictly governed by RFCs, and non-compliance will invariably lead to problems.
- Isolate and test: When troubleshooting, isolate the problematic BIMI record and test its resolution independently using direct DNS queries to precisely pinpoint the source of the issue.
- Check for multi-string TXT records: Ensure the BIMI record is treated as a single string by your DNS provider and not implicitly broken into multiple, concatenated strings, which can cause parsing errors at the receiving end. This is a common issue with multi-string TXT records.
- Leverage advanced DNS query tools: Use command-line tools like dig with specific record type requests (e.g., TXT) to gain precise diagnostic information about your BIMI record's resolution path. Learning how DNSBLs affect deliverability can also provide context on DNS interactions.
Expert from Email Geeks (steve589) suggested checking if the URL for the BIMI image looks broken and is pointing to the correct location. This highlights the importance of the SVG link's validity.
Expert from Email Geeks clarified that the unexpected string returned by a BIMI query is not random. It is a specific DNS lookup result, often indicative of an underlying wildcard record overriding the intended entry.
What the documentation says
Official documentation for BIMI and core DNS standards provides the authoritative rules for record creation and deployment. These documents clearly define that DNS TXT records must adhere to strict formatting guidelines. They also outline critical DNS behaviors, such as the impossibility of CNAME records coexisting with other record types and limitations on character length, all of which can lead to unexpected DNS responses when violated.
Key findings
- TXT record format: BIMI records must be published as DNS TXT records, and their content must strictly adhere to the specified tag-value format, beginning with v=BIMI1;.
- Semicolon usage: While semicolons are used as delimiters within the BIMI record string to separate tags, an extra or misplaced semicolon can lead to parsing errors by receiving DNS resolvers.
- Single string requirement: DNS TXT records are typically expected to be a single string. If the record content is too long, some DNS providers might split it into multiple strings, which can cause issues if not concatenated correctly by the resolver.
- CNAME exclusivity: RFCs (Request for Comments) explicitly state that a CNAME record cannot coexist with any other record types, including TXT records, at the same hostname.
- Wildcard precedence rules: DNS resolution rules dictate that more specific records should take precedence over wildcard records. However, misconfigurations or certain DNS server behaviors can lead to wildcards inadvertently overriding explicit entries.
Key considerations
- Adhere to RFCs: Always consult relevant RFCs (e.g., RFC 1035 for DNS, RFC 6698 for TXT records) for foundational DNS behavior, particularly concerning CNAMEs and TXT record length limitations. Understanding how broken SPF records affect deliverability due to size limits can be helpful.
- BIMI specification review: Reference the official BIMI specification for the exact syntax and requirements of the BIMI TXT record, ensuring every character and tag is precisely placed.
- DNS provider implementation nuances: Recognize that while RFCs provide standards, individual DNS providers may have specific limitations or interpretations regarding TXT record length, especially concerning character string too long errors or multi-string handling.
- Prevent CNAME conflicts: Rigorously ensure that the specific BIMI selector subdomain (e.g., default._bimi.example.com) does not have an existing CNAME record that would conflict with its TXT record, leading to resolution issues.
- Character encoding and escaping: Pay close attention to character encoding and proper escaping within the TXT record, as non-standard characters or incorrect escape sequences can lead to unexpected strings being returned when queried.
- DMARC foundation: Remember that BIMI relies on a properly configured DMARC policy. Reviewing DMARC tags and their meanings can help ensure your overall email authentication is robust.
Documentation from Brand Indicators suggests that BIMI records must be published as a TXT record at a very specific subdomain. This subdomain is typically formatted as `default._bimi` followed by your domain, ensuring precise location for resolvers.
Documentation from RFC 1035 outlines a fundamental rule of DNS that a CNAME record cannot exist with any other resource record type at the same node. This strict rule is a common cause of unexpected behavior when other records, like TXT, are present.
