Re: [idn] iDNS transition: end-system vs. infrastructure?

["Adam M. Costello" <amc@cs.berkeley.edu>]

John C Klensin <klensin@jck.com> wrote:

>  (iii) A family of solutions that are "no risk", because their designs
>  prevent non-IDN-aware applications from ever seeing an IDN in a DNS
>  context.
>
> But let's avoid assuming...that applications will need to handle ACE
> names no matter what.

Could you elaborate on this, with examples?  What sorts of things
would occupy the domain name position in a message header field, or
an SMTP command, or a URI?  Does family (iii) entail revising every
protocol/format that embeds domain names?

What about the case where I send an email message to two people, and one
of them has an IDN address and the other is using a mail program that
predates IDN.  Can the latter reply to all of us?

I might not be understanding what you have in mind, but (iii) looks
difficult to deploy without a lot of effort/pain.

AMC