[idn] IDNs in email message bodies

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

I just looked at the IDNs-in-MUAs talk (thanks to StarOffice).  I agree
with it regarding the mail headers, but I have doubts about performing
ACE conversions in message bodies.

If the Content-Type is text/plain, then the message body is plain
text, pure and simple.  There should be no ACE encoding or decoding
happening there.  You can include strings that happen to be (and look
like) ACE-encoded domain names, and you can include strings that happen
to be (and look like) non-ACE-encoded IDNs, and in either case you can
copy and paste them into your IDN-aware browser (or other application,
including the MUA itself) and it will work (because that application
will perform ACE encoding if necessary).

For MUAs that seek out URL-ish things in plain text message bodies and
turn them into hyperlinks, they may need to perform conversions on the
domain names for the purpose of creating the href attributes, but the
visible text of the link should not be altered.

AMC