[idn] What important would UTF-8 break?

[Dan Oscarsson <Dan.Oscarsson@trab.se>]

There have been a lot of discussion on that the usage of
UTF-8 in DNS would break a lot of things today.

But will it?

DNS as it is today handles UTF-8 in domain names (but do not know
how to compare names case-insensitivly).

All ASCII names will work as before, UTF-8 is fully compatible
with ASCII only for them.

What applications will break?
The most important I can think of is e-mail.
But it need not break. Many wanting to use non-ASCII will
probably have an ASCII name for use in e-mail for many years
more. And the enhanced e-mail applications that those using
non-ASCII in names will use, will handle the conversion
from UTF-8 to ASCII.

Any other important applications?

The most important for me as a system owner would be to have
the OS handle them. Here ACE will never do. Only native names
will do. I would suspect by removing the application code
that restricts host names to ASCII will make a lot of old
code work.

Have anybody done any real tests to see what will work and
what will not? Remember that it is those wanting to use
non-ASCII in names who also quickly will fix their software
to make it work. You can start to introduce UTF-8 names
where it will not break older applications and use ASCII names
where they will.
You cannot just put UTF-8 in DNS and then test what will
break. Few will do like that. If you know that there are
problems you will start using UTF-8 in a way to avoid making
things stop. I am very doubtfull that UTF-8 would introduce
more problems than IDNA/ACE will do.


   Dan