What does a neutral result indicate on the DKIM protocol?

In the context of the DKIM (DomainKeys Identified Mail) protocol, a neutral result indicates that while the email is indeed signed, there are issues concerning the validity of the signature. This aligns with the interpretation that if the signature has syntax errors, it cannot be verified correctly, leading to a neutral result.

When a neutral result is encountered, it signifies that the email might not be fully trustworthy due to the improper structuring or formatting of the signature. This situation arises when, although an attempt was made to sign the email, the signature format does not conform to the expected DKIM syntax rules, making verification unsuccessful.

This is different from the other outcomes that DKIM can produce. For example, a passing signature indicates that everything is in order with the signature, while a failing signature would point to the signature not matching the content or key. Thus, options that suggest the signature is either fully valid or invalid do not capture the specific implications of a neutral result as accurately as acknowledging syntax errors does.