Subject: Re: [idn] nameprep in application may break things

From: Dan <[email-masked]>
Date: Sun, 11 Feb 2001 12:47:31 +0100 (MET)

>>
>>This will break all scripts calling nslookup and the doing simple
>>string matching in the answer to test the result.
>>I am sure there are lots of scripts that expect this behaviour.
>
>One thing you forget is that applications which handle domainnames 
>need to do nameprep, including your "simple script".

All applications will not be fixed at the same time! I am sure there
will be some with nameprep-handling and some without at the same time.

>
>Also, I question whether a DNS server rewrite the query part of a DNS 
>packet. I doubt any DNS server do that.

No they normally do not, but if nslookup does nameprep it will lower case
text before putting it into the query. So the response will contain
a namepreped name instead of the originally entered.

>
>Further, I don't understand what you mean by your conclusion. Why 
>should nslookup not present the non-nameprepped string to the user? 
>You seem to think that nslookup is displaying the string which is the 
>output of the nameprep calculation, but it could aswell be the input.

Many programs handling the result from DNS will decode the response
and display the name form there. Instead of trying to match the
input name with data in the response to be able to output the original
(before nameprep) name.

   Dan

---

From: Patrik Fältström <[email-masked]>
Date: Sun, 11 Feb 2001 13:25:07 +0100

>will be some with nameprep-handling and some without at the same time.

This is why I recommend the IDNA algorithm.

See section 2.1.1 of draft-ietf-idn-idna-00.txt.

    paf