Subject: Re: response code 550 VS 553 Re: [EAI] REVIEW: draft-ietf-eai-smtpext-08.txt

From: "Charles Lindsey" <[email-masked]>
Date: Mon, 01 Oct 2007 11:18:57 +0100

On Sun, 30 Sep 2007 03:52:53 +0100, YAO Jiankang <[email-masked]> wrote:

>> In Section 2.5.  ALT-ADDRESS parameter usage and response codes:
>>
>>   "When messages are rejected because they require UTF8SMTP, the
>>    response code "550" is used, defined in [RFC2821], meaning "mailbox
>>    unavailable".  If enhanced mail system status codes [RFC3463] are"

> After discussion with some editors, we suggest the following text:
>
>
> when messages are rejected because the RCPT TO requires an ALT-ADDRES,  
> the response code 553 is used. When messages are rejected for other  
> reasons, such as MAIL FROM requiring an ALT-ADDRESS, the response code  
> 550 is used.

But please add ", meaning XXXX" after each of "550" and "553", to save the  
poor reader the hassle of dashing or RFC2821 to check what the subtle  
difference is.

-- 
Charles H. Lindsey ---------At Home, doing my own thing------------------------
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---

From: SM <[email-masked]>
Date: Mon, 01 Oct 2007 13:12:43 -0700

At 19:52 29-09-2007, YAO Jiankang wrote:
>when messages are rejected because the RCPT TO requires an 
>ALT-ADDRES, the response code 553 is used. When messages are 
>rejected for other reasons, such as MAIL FROM requiring an 
>ALT-ADDRESS, the response code 550 is used.

I suggest using the 553 response code in the MAIL FROM or RCPT TO if 
the ALT-ADDRESS parameter is required.  Messages are not rejected as 
there isn't a message yet.  It's the mail transaction commands which 
are rejected.

The suggested text is:

   When the ALT-ADDRESS parameter is required in the MAIL command or RCPT
   command and it is not specified, the SMTP Server MUST return a 553 (mailbox
   name not allowed) reply code as defined in [RFC2821].  If enhanced 
mail system
   status codes [RFC3463] are used, the status code should be "5.6.x"
   [SMTP-codes], meaning that "The alt-address is required but not specified".

   If the message is rejected after the DATA command is completed with
   <CRLF>.<CRLF> because it requires a UTF8SMTP downgrade, the 554 (Transaction
   failed) reply code as defined in [RFC2821] is returned.  If enhanced mail
   system status codes [RFC3463] are used, the status code should be "5.6.z"
   [SMTP-codes], meaning that "UTF8SMTP downgrade failed".

Regards,
-sm

---

From: Harald Alvestrand <[email-masked]>
Date: Mon, 01 Oct 2007 22:58:06 +0200

SM skrev:
>> ALT-ADDRES, the response code 553 is used. When messages are rejected
>> for other reasons, such as MAIL FROM requiring an ALT-ADDRESS, the
>> response code 550 is used.
>
The recieving SMTP server can't reject on the MAIL FROM, because it
doesn't know anything about the destination yet (presumably if a server
announces UTF8SMTP support, it is able to deliver a message/global to
SOME recipients). If the response is on RCPT TO, it seems highly
confusing to a protocol machine (that doesn't read explanatory text) if
the exchange is:

-> MAIL FROM: <utf8@utf8>
<- 250 Go ahead, I will see what I can do
-> RCPT TO: <utf8@utf8> ALT-ADDR=<ascii@ascii>
<- 553 Mailbox name not allowed - MAIL FROM address didn't have ALT-ADDR

Of course, one can reply

<- 550 5.6.foo Can't send a message with this FROM address to this
recipient - no ALT-ADDR

where 5.6.foo is a new status code defined in this document, because we
define the meaning of 5.6.foo.

But we don't define the meaning of 553.

                   Harald

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From: SM <[email-masked]>
Date: Mon, 01 Oct 2007 15:44:58 -0700

><- 553 Mailbox name not allowed - MAIL FROM address didn't have ALT-ADDR

The example I was thinking of is:

-> RCPT TO:<uft8@utf8>
<- 553 text

The protocol machine does not read the explanatory text.  It only has 
to deal with the reply code.  In the above case, the ALT-ADDRESS is 
required for the RCPT.

>But we don't define the meaning of 553.

The current draft provides the meaning of the 550 and 554.

Regards,
-sm

---

From: Harald Alvestrand <[email-masked]>
Date: Tue, 02 Oct 2007 07:53:21 +0200

> to deal with the reply code.  In the above case, the ALT-ADDRESS is
That's consistent with the text suggested by Yao.