[ietf-dkim] Internationalized domain names

[Douglas Otis]

On Jul 19, 2006, at 10:29 AM, Paul Hoffman wrote:

>>
>> Agreed.
>>
>> Calling this an ACE label which is identified by the "xn--" prefix  
>> may avoid some of the confusion.
>>
>> This could also be written as:
>>
>>  Internationalized domain names MUST be converted using the
>>  steps in section 4 of [RFC3490] into "ACE" labels using the
>>  ToASCII function.
>
> No, that's wrong: only the labels that have non-LDH characters are  
> converted. Section 4 in IDNA covers this correctly.

Good point, but not exactly right either.  A term for international  
domain names encoded into ACE labels would provide a useful  
reference, rather than calling this puny-code.  The '_' underscore  
character is also not one of the 37 case-insensitive LDH (letter,  
digit, or hyphen) characters either, but the intent is not to include  
this label within this requirement.  While domain name encoding is  
specifically mentioned with the i= parameter where there are  
essentially no character restrictions for subdomains, this statement  
also applies to the d= tag as well.

Perhaps:

  Internationalized domain names MUST be converted using the
  steps in section 4 of [RFC3490] into "ACE" labels when
  appropriate by applying the ToASCII function for "stored stings."
  This requirement does not apply to the "_domainkey" label.

-Doug