>> The draft: idn-idna: >> The ToASCII must be applied to ALL labels containing non-ASCII. > >Rule 1 already says: > > Whenever a domain name is put into a generic domain name slot, every > label MUST contain only ASCII characters. > >"every label".
Yes, but not all labels in DNS are "generic domain name slot" from what I can understand. For example the e-mail name label in the SOA record. > >> The steps need a slight change: >> - character restrictions will apply depending on label, it could be >> host name or e-mail name. > >Step 3 of ToASCII already says "If the label is part of a host name (or >is subject to host name syntax rules) then perform these checks". > >When you say "e-mail name" do you mean the local part (before the @)? >That's outside our jurisdiction. Another working group will have to >decide how to internationalize email local parts. We can only tell how >to deal with domain names. That is right, but the ACE encoding is not what defines the way to internationalise host names. ACE is a transport encoding. To support the future standard of non-ASCII characters in e-mail, the labels in DNS that are used for e-mail must handle non-ASCII characters. You could have the e-mail group define a "E-nail ASCII Compatible Encoding" but that is really stupid to have in DNS. Thare should only be ONE way to encode non-ASCII on top of ASCII in DNS. There are already to many different ways to encode non-ASCII on top of ASCII and it is a very difficult thing to handle in software. Therefore we should have ONE standard for all labels in DNS. >> - Encoding into ACE must use Punycode WITH case marking so that >> case can be restored when using ToUnicode. >> >> ToUnicode is fine, but decoding Punycode must restore case. > >I have already argued for mixed-case support as best I can. I couldn't >quite get it *mentioned* in the IDNA and Nameprep documents. You don't >have a prayer of getting it *required*. > >Of course, the working group that internationalizes email local parts >would have the option of writing a spec that requires Punycode with >mixed-case support. Yes, that is one of the reasons why case should be preserved during ACE conversion in DNS. To suppport the systems that require case preservation. Dan
