New version of strawman for IDNAv2

John C Klensin klensin at
Mon Mar 2 18:13:09 CET 2009

--On Monday, March 02, 2009 17:26 +0100 Stephane Bortzmeyer
<bortzmeyer at> wrote:

> On Sun, Mar 01, 2009 at 10:59:33PM +0000,
>  Adam M. Costello
> <idna-update.amc+0+ at> wrote   a
> message of 26 lines which said:
>> How common is it for applications to display domain names
>> obtained from DNS?  I'm not aware that this ever happens
>> except for logging/debugging purposes.
> traceroute ? Yes, it is a debugging tool but it is very common.

In addition to this example and the email trace header examples
already given, some versions of ping will attempt to reverse-map
if given an IP address.  A situation analogous to the
reverse-mapping case is also important: I haven't kept up with
how many of them are doing it, but, during the lengthy early
rounds of discussion of what browser vendors should be doing to
impede phishing, one suggestion, which appeared to have broad
support at the time, was to display only the forms that were
reverse-translated from the ACE form (forms that we would call
U-labels today) and not whatever might map to them.   My guess,
although it is just speculation, is that behavior will be even
more common in non-web applications than it has been in the web
ones if mapping (anywhere) is encouraged.


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