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

----- Original Message ----- 
From: "Chris Newman" <chris.newman@oracle.com>
To: "Joseph Yee" <jyee@afilias.info>
Cc: <ima@ietf.org>; "Jiankang Yao" <healthyao@gmail.com>
Sent: Tuesday, August 09, 2011 4:39 AM
Subject: Re: [EAI] I-D Action: draft-ietf-eai-rfc5336bis-11.txt

> --On August 3, 2011 14:44:06 -0400 Joseph Yee <jyee@afilias.info> wrote:
>>>>> 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.
> 
> A "host-not-found" error is close but not entirely accurate since a UTF-8 
> domain that can't be converted to an A-label can't even be looked up to 
> determine if the host exists...
> 
> But I looked in RFC 3463 again and noticed there are correct codes that an 
> MSA/MTA could use for this case.
> 
> MAIL FROM:   501 5.1.7 Bad sender's mailbox address syntax
> RCPT TO:     501 5.1.3 Bad destination mailbox address syntax
> 
> So I think mentioning those codes for the case where a UTF-8 domain can't 
> be converted to an A-label would be helpful.
> 

In the  case where a UTF-8 domain can't  be converted to an A-label, 
 we can regard it as the bad mailbox address syntax as pointed out by your example above.
The invalid address may be caused by invalid U-lable or Local-part.

Since the RFC 3463 has defined it, giving it more detailed distinction may not bring us more help.

Jiankang Yao

> - Chris
> 
> 
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