Re: idna-bis and 'ß'

Harald Tveit Alvestrand harald at
Fri Nov 23 19:16:43 CET 2007

According to the tables at the back of draft-faltstrom-idnabis-tables-03, 

It's an user interface issue what to do when the user types a LATIN SMALL 
LETTER SHARP S; idnabis deliberately does not require that one maps it to 


--On 23. november 2007 07:06 -0800 Paul Hoffman <phoffman at> wrote:

> At 6:07 PM -0500 7/26/07, Thomas Roessler wrote:
>> In the current IDNA environment, the 'ß' character (latin small
>> letter sharp s) is mapped to the all-Latin string "ss".  Therefore,
>> no traces of that character can be found in zone files or
>> registration databases; however, references to domain names (even
>> all-ASCII ones) can be written in that fashion, and presented on
>> business cards, in printed material, and in IRIs.
>> I understand that the current state of idna-bis would lead to
>> treating 'ß' as a "usual" character, causing a different encoding of
>> relevant input strings.  Taking that step in idna-bis would cause
>> existing references written with the 'ß' character (and possibly
>> resolving to all-ASCII domain names) to break.
>> As a cure, the current mapping behavior should be preserved as an
>> exception.
> To Patrik, John, et. al.: Is there a list of characters from IDNA that
> are mapped to ASCII that are proposed to map to non-ASCII in idnabis?
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