Internationalized Domain Names in Applications (IDNA): Registry Restrictions and Recommendations

The information below is for an old version of the document
Document Type Expired Internet-Draft (individual in art area)
Authors John Klensin  , Asmus Freytag 
Last updated 2017-09-12 (latest revision 2017-03-11)
Stream Internet Engineering Task Force (IETF)
Expired & archived
pdf htmlized bibtex
Additional Resources
Stream WG state (None)
Document shepherd No shepherd assigned
IESG IESG state Expired (IESG: Dead)
Consensus Boilerplate Yes
Telechat date
Responsible AD Alexey Melnikov
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The IDNA specifications for internationalized domain names combine rules that determine the labels that are allowed in the DNS without violating the protocol itself and an assignment of responsibility, consistent with earlier specifications, for determining the labels that are allowed in particular zones. Conformance to IDNA by registries and other implementations requires both parts. Experience strongly suggests that the language describing those responsibility was insufficiently clear to promote safe and interoperable use of the specifications and that more details and some specific examples would have been helpful. This specification updates the earlier ones to provide that guidance and to correct some technical errors in the descriptions. It does not alter the protocols and rules themselves in any way.


John Klensin (
Asmus Freytag (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)