.....Due to the ASCII character encoding being the core/monopoly
This is a bad start: non-ASCII characters are used on the Internet for
many years. There is certainly an ASCII *bias* in many Internet
protocols, applications or deployments but if there was an ASCII
*monopoly*, it ended a long time ago.
From draft-ietf-idnabis-protocol-03.txt Section 6.1:
The current update to the definition of the DNS protocol [RFC2181]
explicitly allows domain labels to contain octets beyond the ASCII
range (0000..007F), and this document does not change that. Note,
however, that there is no defined interpretation of octets 0080..00FF
as characters. If labels containing these octets are returned to
applications, unpredictable behavior could result. The A-label form,
which cannot contain those characters, is the only standard
representation for internationalized labels in the current DNS
As noted above, the DNS protocol does not prohibit the carrying
of non-ASCII characters; the issue is the response of applications to receipt
of such characters in responses. Presumably applications written to
UNICODE APIs such as GetAddrInfoW are capable of handling UTF-8 in
responses, and indeed there are many such applications (e.g. applications
depending on .NET/mono DNS classes).
presently you cannot have domain names that are multilingual, for
example: japanese and english language mixed character domain names,
hindi and english language mixed character domain names etc.
Since it is an IETF mailing list, I will focus on what depends on
IETF, technical standards. There is *nothing* in the current IDN
standard (machine names in Unicode) that forbids such mixes. You may
refer to bad policies like ICANN IDN Guidelines, which apparently
forbid mixing scripts, but this had nothing to do with the IETF,
nothing to do with the protocols.
From draft-ietf-idnabis-rationale-01.txt Section 14:
To help prevent confusion between characters that are visually
similar, it is suggested that implementations provide visual
indications where a domain name contains multiple scripts. Such
mechanisms can also be used to show when a name contains a mixture of
simplified and traditional Chinese characters, or to distinguish zero
and one from O and l. DNS zone administrators may impose
restrictions (subject to the limitations identified elsewhere in this
document) that try to minimize characters that have similar
appearance or similar interpretations. It is worth noting that there
are no comprehensive technical solutions to the problems of
confusable characters. One can reduce the extent of the problems in
various ways, but probably never eliminate it. Some specific
suggestions about identification and handling of confusable
characters appear in a Unicode Consortium publication
This is *not* a prohibition, but rather a suggestion; Section 4 of the document
contains no restriction on the registration of labels with mixed scripts.
Similar advice can be found in RFC 3490 Section 10.
Another example, there is not much browser / URL bar integration and
usability innovation that allow for a non-ASCII language domain name
to stay non-ASCII script on the browser / URL bar without it
changing to Punycode.
From draft-ietf-idnabis-rationale-01.txt Section 7.2:
allow the display and user input of A-labels, but are encouraged to
not do so except as an interface for special purposes, possibly for
debugging, or to cope with display limitations. A-labels are opaque
and ugly, and, where possible, should thus only be exposed to users
and in contexts in which they are absolutely needed. Because IDN
labels can be rendered either as the A-labels or U-labels, the
application may reasonably have an option for the user to select the
preferred method of display; if it does, rendering the U-label should
normally be the default.
Indeed, there are browsers (e.g. Safari) that actually follow this advice (and
provide a more pleasant user experience as a result).
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