@techreport{rodenhaeuser-idna-transparent-resolution-00, number = {draft-rodenhaeuser-idna-transparent-resolution-00}, type = {Internet-Draft}, institution = {Internet Engineering Task Force}, publisher = {Internet Engineering Task Force}, note = {Work in Progress}, url = {https://datatracker.ietf.org/doc/draft-rodenhaeuser-idna-transparent-resolution/00/}, author = {Luca Rodenhäuser}, title = {{Transparent Handling of Internationalized Domain Names in Name Resolution APIs}}, pagetotal = 20, year = 2026, month = jul, day = 18, abstract = {Applications are expected to convert internationalized domain names to their ASCII-Compatible Encoding (A-label) form before invoking name resolution APIs. In practice this conversion is performed inconsistently: different applications follow different IDNA standards, use different libraries, and ship different versions of the Unicode mapping tables, so that the same input string can resolve to different registrable domain names depending on which software component performs the conversion. This document specifies that name resolution services accept Unicode host names by default and perform the conversion to A-labels internally, exactly once, at the point where a name is handed to a specific resolution protocol. The DNS wire format is unchanged: only A-labels appear in queries to the public DNS. The conversion procedure is Unicode IDNA Compatibility Processing (UTS \#46), nontransitional, with a mapping-table floor of Unicode 15.1. This codifies the architectural recommendation of RFC 6055 and the deployed practice of several major platforms.}, }