[idn] IDNA in real life

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

Looking at IDNA and how it would enable me to use
non-ASCII host names on my system, I see only two useful stages:

1) "do nothing".
   No change done anywhere in any software.
   Here I would be able to access other places with
   non-ASCII in host names using the ACE form.
   But it will be ugly for host names that can be expressed
   in my local character set and if somebody get a name in
   the native non-ASCII form they will not be able to use it,
   as they do not know how to convert it into ACE (and will
   see it as absurd that you have to convert it to ACE).
   It will be impossible to use non-ASCII host names on my own
   hosts.


2) "do everything".
   Implement conversion between native local character set and
   ACE encoded names in the resolver libraries and replace the ones
   delivered with my systems so that all applications get
   host names in native form. My DNS server must be upgraded
   so it can load zone files in native local character set and
   sendmail will have to be fixed so it can convert host names
   to ACE before sending. There might be some operating system
   software that does it own checking on what character are
   allowed in host names, will have to require them fixed
   by OS vendor.
   When that is done, most things should work with non-ASCII
   host names. I can define hosts with such names, use web
   pages and send e-mail.


There is really no between stage. I cannot do an incremental upgrade.
It is unacceptable to require people to enter or see ACE encoded names
in the commonly used places. This includes URLs, log files, /etc/hosts,
DNS zone files and configuration files. So I cannot get any
incremental change over to native host names like the IDNA solution
hopes. Instead I will have to wait until I in some way can
get all important software to change at the same time. That is why
the easiest way to do it is by changing the resolver library instead
of changing each application.
As IDNA promotes the use of ACE, many vendors with little understanding
for the need of non-ASCII characters will just use ACE, I can expect
a long wait before applications handle native host names instead of ACE
unless you can force it on them by for example changing the resolver
library.

I have not tried to modify my resolver library so I do not know
how many applications it will break. And as the resolver library
is delivered with the OS I might have to fix it in the DNS server
instead if decide I do not dare trying to replace the resolver library.
Clearly, IDNA will not very much help my systems in the move to
using non-ASCII in host names. Neither would UTF-8, but as the break
with the ASCII world would be much more apparent I would expect
applications to be fixed quicker.

    Dan