Re: [idn] IDNs in email message bodies

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

William Tan <william.tan@i-dns.net> wrote:

> > If the person doing the copy/paste was using an IDN-aware MUA with
> > support for Arabic, then the From: field was showing Arabic text,
> > and that is what got copied and pasted, not ACE, so there will be no
> > irritation.
>
> If the recipient system is not IDN aware, it would break, defeating
> the purpose of IDNA.

If your system is IDN-unaware, then a raw (non-ACE) IDN is useless
to you, regardless of whether you see it on a business card, on a
billboard, or in an email message body.  I think that's acceptable.  At
least you can always reply to any email you receive.

> And even if it is IDN aware, it might not support the character set
> being used to represent the IDN email address.

If you receive a message encoded using a character set that your system
does not support, then the entire message body is useless, including any
email addresses contained in it.  I think that's acceptable.

Maynard Kang <maynard@i-email.net> wrote:

> I think most will fully agree that bq--xxx.cn in bodies should be
> displayed as it is.  But how about bq-xxx.cn in headers, especially
> headers which contain an addr-spec, route or domain? That is the
> tricky bit.

I think IDN-aware MUAs should by default decode the ACE in an addr-spec,
route, or domain that appears in a structured header field.  But it
should be possible for the user to turn off this decoding, in case the
ACE is needed for some reason.

Edmon <edmon@neteka.com> wrote:

> > 4. MUA uses the ACE in RFC822 From: and To: headers (as recommended
> > in idn-mua I-D)
>
> I dont agree with 4.  I believe that it is sufficient to use 2&3 and
> leave the headers to be in existing MIME format because headers are
> for display only.

RFC 822 does not allow non-ASCII characters in domain names in
structured header fields (like From: and To:), and MIME does not change
that rule, so the only way to use IDNs there (without changing RFC 822)
is via ACE.

This is the only way that non-IDN-aware MUAs will be able to reply to
messages sent from IDN addresses.

Patrik Fältström <paf@cisco.com> wrote:

> the application which put things in the clipboard buffer should do it
> in the ace encoding

I disagree for two reasons.  First, if I highlight Japanese text and it
gets transformed into ACE when I pasted it, I'm going to be surprised
and annoyed.  Second, what you propose is simply impossible in many
cases.  For example, my MUA is Mutt running inside an xterm.  Mutt
has no control over how copying and pasting happens, because it's all
handled by xterm.

AMC