Re: [EAI] I-D Action: draft-ietf-eai-rfc5336bis-11.txt

I agree with Joseph's comments about this issue.
On the other hand, SMTP does not allow to judge whether the domain name is valid or not.

Jiankang Yao

----- Original Message ----- 
From: "Joseph Yee" <jyee@afilias.info>
To: "Chris Newman" <chris.newman@oracle.com>
Cc: "Jiankang Yao" <healthyao@gmail.com>; <ima@ietf.org>
Sent: Thursday, August 04, 2011 2:44 AM
Subject: Re: [EAI] I-D Action: draft-ietf-eai-rfc5336bis-11.txt

> 
>>> 4. In section 3.5, I suggest adding an enhanced status code for the case
>>> where a U-label can not be converted to an A-label. This is semantically
>>> quite different from X.6.7 and X.6.9
>> 
>> based on rfc5890, U-label must be transformed to A-label, otherwise, it
>> can not be called U-label.
>> 
>> John should be authoritive about the defintion of U-label.
> 
> This does not prevent a broken client from generating a UTF-8 domain that is not a valid U-label and thus can not be converted to an A-label. It's an error a well-intentioned client implementer can make by mistake. And it's a subtle error condition a processor may not expect. For those reasons, I think it's useful to distinguish it from the class of "recipient-can't-handle" errors.

I'm not sure if a different error code can help end users at the moment.  Unless you mean MSA/MTA to detect and report U-label => A-label failure, otherwise it is only "recipient-can't-handle" or "host-not-found".

Would love to hear more feedback from everyone regarding this.

Best
Joseph

> 
> - Chris
> 
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