Eszett (Sharp-S) again (was: Re: AW: Oustanding issues tracking)

John C Klensin klensin at
Wed May 28 08:44:58 CEST 2008


Many thanks.  This was exactly the clarification I was looking
for.  And I agree that "your point of view" is not open for
debate here -- I was just hoping that we could understand what
that point of view was.


--On Wednesday, 28 May, 2008 08:20 +0200 "Marcos Sanz/Denic"
<sanz at> wrote:

>> (2) If we treat Eszett as a separate character, we create a
>> fairly nasty incompatibility between IDNA2003, where it maps
>> to "ss" and disappears and IDNA2008, where it is separate.
>> Preventing that incompatibility from being a nasty problem
>> would require some very careful action by the relevant
>> registries (as usual, in the "zone administrator" sense, not
>> just TLD registries).  Possibly a well-designed variant
>> strategy would be sufficient, possibly not.   We haven't
>> heard from the most obvious registries yet as to whether they
>> would be willing to deal with this.
> If eszett were to be added to the IDNA2008 tables as
> protocol-valid, DENIC  probably would, after the standard is
> passed, allow eszett registration  under the DE TLD. Since
> that codepoint was not allowed for registration  until now
> (i.e. no mapping eszett->ss occurred within the registry),
> there  is no "nasty problem" here from our point of view. When
> typing eszett in a  domain name while browsing, some users
> (IDNA2003) would certainly end up  at the ss-mapped-name, some
> other users (IDNA2008) would end up at the  eszett-name. Still
> from our point of view (which is not up for debate  here),
> usage of variants at the registry would not be an appropriate 
> technique for dealing with this issue. On the contrary, it
> would be my  recommendation for all ss-mapped-name-registrants
> to apply for  registration of the corresponding eszett-name,
> where applicable. Maybe  registrars could automatically do
> this for their customers, I actually  don't mind. And if the
> eszett-name would already have been registered by a  different
> registrant, chances are very high that the corresponding 
> ss-mapped-name-registrant would win a dispute on the
> eszett-name.
> Best regards,
> Marcos
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