Re: [idn] Let's go forward with IDNA and UTF-8

[Mats Dufberg <dufberg@nic-se.se>]

On Sun, 27 May 2001, Dan wrote:

> >ACE approach is NOT destroying any information when data is sent from
> >sender to receiver in any of the protocols we have today. It is 100%
> >backward compatible.
> Probably 100%, but some software may compare an ACE version of the name
> with thde decode version and fail.
>
> But ACE+nameprep IS destroying information.
>
> Also ACE can only be used for host names, if may not fit all types of
> DNS names and it cannot be used for other textual data in DNS.

Well, nameprep+UTF-8 will cause the same problem when it comes to the name
part. There is no difference in what codepoints that ACE can handle
compared to UTF-8. Nameprep is there to eliminate ambiguity, and will be
needed for any solution (ACE, UTF-8) to avoide chaos in DNS.

> So by using ACE you always need to implement handling of UTF-8 (or what
> is used) for all other textual data in DNS.

Hm. I guess that some kind of ACE would be better if ACE coding is used
for the names.

> There is one major difference between MIME and ACE/UTF-8 in DNS.

The point is that 8-bit data could be transported through 7-bit-only
server through encoding (quoted-printable, base64). As long as the mail
clients in each end could handle MIME they could use 8-bit character set.

The parallell with the ACE solution is clear.


Mats

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Mats Dufberg                                     +46-8-545 857 06
dufberg@nic-se.se                           fax: +46-8-545 857 29