Re: [idn] Where will we see bad domain names?

["D. J. Bernstein" <djb@cr.yp.to>]

Martin J. Duerst writes:
> The classical case is half-width and full-width alphabetics and
> Katakana in Japan.

But we've already learned that nameprep doesn't solve the Japanese
name-typing problem. People in Japan aren't getting the right dots.

The obvious solution is to improve the address-typing support in the
operating system's Japanese keyboard interface. That's the only piece of
software that has to worry about bad domain names. It will provide a
friendly Japanese-specific environment for typing good domain names. It
will deal with the dot problem.

Done.

In contrast, Patrik and Bill want us to add bad->good conversion code
(and Japanese dot handling) to Outlook, Messenger, Eudora, Mutt, Pine,
Sendmail (which will have to check whether incoming IDNs match UTF-8
domain names in user-typed configuration files), qmail (same reason),
Exchange, IMail, Exim, Post.Office, Explorer, Communicator, Opera, Lynx,
w3m, Apache, IIS, Enterprise, WebLogic, Zeus, BIND, djbdns, Webmin, etc.

That is not good software engineering.

Of course, if every one of those programs has to be changed, then every
one of them has to be redeployed. Patrik claims that this is necessary
for full IDN support. But my solution will allow some of these programs
to be left alone: they can already handle UTF-8 IDNs without trouble.

---Dan