Subject: [EAI] IMAP and POP downgrade when SMTP downgrade would have bounced?

From: Harald Alvestrand <[email-masked]>
Date: Mon, 28 Aug 2006 09:51:38 +0200

Both the IMAP and POP drafts currently specify something like a 
mechanism for downgrading a stored UTF8SMTP message to ASCII by pointing 
at the -downgrade document.

What is the correct action to take when such a downgrade is attempted, 
and one encounters a case where the -downgrade SMTP gateway would have 
bounced the message?

                            Harald

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From: [email-masked]
Date: Mon, 28 Aug 2006 17:37:12 +0900 (JST)

> From: Harald Alvestrand <[email-masked]>

In my understanding, IMAP and POP document refers downgrade-02 section
5 "SMTP DATA/Header Downgrading".

> and one encounters a case where the -downgrade SMTP gateway would have 

Consider that From: header has a non-ASCII address without an
alternative US-ASCII address case.
After downgrading, original non-ASCII From: header is preserved in
Downgraded: header, but From: header becomes empty.

Return-Path:, To:, CC: header have the same problem.

Empty From: header or without From: header is allowed?

--
Kazunori Fujiwara, JPRS

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From: Harald Alvestrand <[email-masked]>
Date: Mon, 28 Aug 2006 01:40:43 -0700

> Empty From: header or without From: header is allowed?
It is not allowed by RFC 2822.

I had always thought that if you encountered a missing alt-addr in the 
headers, the correct course was to bounce the message, rather than 
deliver a message where "reply" would not work.

I was surprised when I discovered the "remove the address" option in 
-downgrade.

What does the WG think desirable?

                Harald

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From: "Charles Lindsey" <[email-masked]>
Date: Mon, 28 Aug 2006 15:38:40 +0100

> What does the WG think desirable?

Whilst it might be impossible to deliver some message in UTF-8 form to  
some sites (because it could not be downgraded for some reason), what we  
have here is a case where it apparently _was_ delivered (or otherwise  
arrived in) some POP3 or IMAP box in UTF-8 form. In that case, I see no  
reason why the owner of that box should not process it in ayway he  
chooses, so if he asks to see it downgraded, then he will get whatever our  
downgrade document says. That may not be a valid RFC 2822 message (in  
which case it will fail to get anywhere if the box owner tries to resend  
it). But that is no reason why the box owner should not be shown the  
message. In IMAP, in particular, he may be able to fix the missing From  
line manually, and then resend it. But it would be nice if IMAP had warned  
him that the downgrade had produced a dubious message.

-- 
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