Subject: [idn] idn-uri document

From: Erik Nordmark <[email-masked]>
Date: Fri, 13 Sep 2002 19:09:09 +0200 (CEST)

Martin,

I just read draft-ietf-idn-iri-01 and I have some comments and
questions.

I don't know if the best place to discuss this is the IDN list, or
if there is some other list looking at URI/IRI stuff.

On page 4 it says "will always be rejected by resolvers".
I don't know if this is intended to be a statement about the current
implementations of resolvers, or a statement about something we should
recommend or require resolvers to do.
I do think there currently are resolvers which happily pass whatever
string of octets into DNS packets and send them off.
And I'm far from certain it would be a good idea recommend or mandate 
that resolvers do additional checks. The IDNA model is that the clients
do nameprep and that the DNS servers just to a (ASCII case insensitive)
exact match. 

The defined syntax rules for declare certain ASCII domain names illegal
(such as *.example.org). Where is the check for illedgal names assumed to
be performed? For IDNA it probably makes sense to only apply this types
of checks (setting the UseSTD3ASCIIRules flag) when verifying domain name 
registrations and not do such checks in the clients. 

     The work of the IDN WG includes some procedures for name preparation
    [Nameprep].  Before encoding an internationalized domain name in an
    URI, this preparation step SHOULD be applied.  However, the URI
    resolver MUST also apply any steps required as part of domain name
    resolution by [IDNA].

The above statement says that for all domain names (note that the term
"IDN" is defined to include the existing ASCII domain names)
one should apply nameprep. This might be fine but it makes sense
stating this explicitly. The ToASCII in IDNA does not apply nameprep
to all-ASCII labels. Always applying nameprep will have the effect
of downcasing the ASCII characters in all ASCII labels, which IDNA does not
do.

Which are the "any steps required as part of domain name resolution"
above? I can't figure out to what it might refer.

Finally, is the intent that nameprep always be applied before characters
are encoded in UTF-8? Then it makes sense stating that in the first real 
paragraph on page 4.

  Erik