RFC 3490 (rfc3490) - Page 1 of 22


Internationalizing Domain Names in Applications (IDNA)



Alternative Format: Original Text Document



Network Working Group                                       P. Faltstrom
Request for Comments: 3490                                         Cisco
Category: Standards Track                                     P. Hoffman
                                                              IMC & VPNC
                                                             A. Costello
                                                             UC Berkeley
                                                              March 2003


         Internationalizing Domain Names in Applications (IDNA)

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2003).  All Rights Reserved.

Abstract

   Until now, there has been no standard method for domain names to use
   characters outside the ASCII repertoire.  This document defines
   internationalized domain names (IDNs) and a mechanism called
   Internationalizing Domain Names in Applications (IDNA) for handling
   them in a standard fashion.  IDNs use characters drawn from a large
   repertoire (Unicode), but IDNA allows the non-ASCII characters to be
   represented using only the ASCII characters already allowed in so-
   called host names today.  This backward-compatible representation is
   required in existing protocols like DNS, so that IDNs can be
   introduced with no changes to the existing infrastructure.  IDNA is
   only meant for processing domain names, not free text.

Table of Contents

   1. Introduction..................................................  2
      1.1 Problem Statement.........................................  3
      1.2 Limitations of IDNA.......................................  3
      1.3 Brief overview for application developers.................  4
   2. Terminology...................................................  5
   3. Requirements and applicability................................  7
      3.1 Requirements..............................................  7
      3.2 Applicability.............................................  8
         3.2.1. DNS resource records................................  8



Faltstrom, et al.           Standards Track