Impact of Punycode

John C Klensin klensin at
Thu Mar 25 23:05:21 CET 2010

-On Thursday, 25 March, 2010 18:33 +0000 Shawn Steele
<Shawn.Steele at> wrote:

> I am suggesting that for Email, the EAI approach is less
> problematic.  Yes, e-mail servers will need updated, but there
> will be less long-term confusion.


Without in any way disagreeing with Patrik's or Vint's comments,
let me also note that there is an extremely basic difference
between the DNS situation and the email one.  With the latter,
we are using a very carefully defined extension mechanism in
which the client gets to find out if the server is prepared to
handle certain types of strings (in this case, UTF-8 addresses)
and then to announce that such a string is coming.   If the
server doesn't like strings of that sort, it never sees them
(unless the client is very, very, broken).   The DNS permits no
such negotiation or authorization, which completely changes the



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