RFC 6122, "Extensible Messaging and Presence Protocol (XMPP): Address Format", March 2011

Note: This RFC has been obsoleted by RFC 7622

Errata ID: 2801
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Florian Zeitz
Date Reported: 2011-05-07
Held for Document Update by: Robert Sparks

Section 2.2 says:

When preparing a text label (consisting of a sequence of UTF-8 encoded
Unicode code points) for representation as an internationalized label
in the process of constructing an XMPP domainpart or comparing two
XMPP domainparts, an application MUST ensure that for each text label
it is possible to apply without failing the ToASCII operation
specified in [IDNA2003] with the UseSTD3ASCIIRules flag set (thus
forbidding ASCII code points other than letters, digits, and
hyphens).

It should say:

When preparing a text label (consisting of a sequence of UTF-8 encoded
Unicode code points) for representation as an internationalized label
in the process of constructing an XMPP domainpart, an application MUST
ensure that for each text label it is possible to apply without failing the
ToASCII operation specified in [IDNA2003] with the UseSTD3ASCIIRules flag set
(thus forbidding ASCII code points other than letters, digits, and hyphens).
When comparing two XMPP domainparts, an application MUST first apply the
[NAMEPREP] profile of [STRINGPREP] to both domainparts and perform a byte-wise
comparison afterwards.

Notes:

As is the RFC does not specify how to compare XMPP domainparts. It should have been pointed out that normalization is required and how to do that normalization.

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