YAO Jiankang yaojk at
Fri Dec 7 01:32:49 CET 2007

Thanks fujiwara for raising this question.
if  the first requirement in RFC 3490 section 3.1 is removed, I also really care for it.
If it is removed, it will cause much inconvenience for CJK communities. 

YAO Jiankang

----- Original Message ----- 
From: <fujiwara at>
To: <klensin at>
Cc: <idna-update at>
Sent: Friday, December 07, 2007 5:31 AM
Subject: Dot-mapping

> Dear IDNAbis authors,
> I found that RFC 3490 section 3.1 the first requirement is removed in
> the new protocol document draft-klensin-idnabis-protocol-02.
> |  1) Whenever dots are used as label separators, the following
> |     characters MUST be recognized as dots: U+002E (full stop), U+3002
> |     (ideographic full stop), U+FF0E (fullwidth full stop), U+FF61
> |     (halfwidth ideographic full stop). 
> And John described this reason.
> Is removing the dot-mapping already decided?
> The dot-mapping has useful in some language enviromnet.
> The dot-mapping is already implemented in many applications.
> Removing it causes many problems.
> I'm afraid that another languages may have the same problem and the
> characters which need to be treated as a dot may increase.
> Regards,
> --
> Kazunori Fujiwara, JPRS
>> Subject: IDNAbis discussion style, mappings, and (incidentally) Eszett
>> From: John C Klensin <klensin at>
>> To: idna-update at
>> Date: Thu, 29 Nov 2007 18:14:12 -0500
> ---snip---
>> So the draft IDNA200X documents take the dot-mapping provision
>> out, turning the parsing of all domain names, including those
>> that contain A-labels, back over to the rules of RFC 1034 and
>> 1035 and the acceptance of special dots into a UI issue. To me,
>> the arguments for that choice are overwhelming.  But it is a
>> tradeoff against user-predictable behavior with scripts that
>> use non-ASCII dots and compatibility with existing non-protocol
>> text that represents IDNs using those dots: if applications
>> that map between such text and the IDNA protocol don't do the
>> right UI things with dots other than U+002E, bad things will
>> happen.  And, if we work the tradeoffs so that types of
>> compatibility issues overwhelm the reasons why special dot
>> mapping was a bad idea, then we are stuck with the special dots
>> forever.  
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