Re: [dmarc-ietf] ABNF errors on RFC7489 and dmarcbis-07

[John Levine <[e-mail]>]

It appears that Damian Lukowski  <[e-mail]> said:
>> In practice, the code that parses DMARC just splits the input into
>> xxx=yyy pairs of tag and value strings and checks the values
>> semantically.
>
>For those, who do not work at the IETF,

Nobody here works at the IETF.

> the spec comes before the implementation. 

Well, sometimes.  The most successful IETF standards are generally ones that document
and clarify existing practice rather than that invent something totally new.

>> Unknown tags MUST be ignored.  Syntax errors in the remainder
>> of the record SHOULD be discarded in favor of default values (if any)
>> or ignored outright.

Now that I look at it, the whole ABNF section is confused. I would
delete the second sentence in that section, and simplify the ABNF to
say that it's a mostly unordered list of tag=value clauses. Then make
a second section showing the syntax of the clauses that mean
something, and don't offer any advice for what to do with syntax
errors. If you want to interoperate, follow the spec. If you don't
follow the spec, you're on your own.

R's,
John