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Re: [ietf-smtp] Are A-label and U-label addresses supposed to be equivalent ?

2020-07-12 21:54:47

From: John R Levine
Date: 2020-07-12 12:13
To: John C Klensin; ietf-smtp
CC: YAO Jiankang
Subject: Re: [ietf-smtp] Are A-label and U-label addresses supposed to be 
equivalent ?
On Sat, 11 Jul 2020, John C Klensin wrote:
[ Are corresponding A-label and U-label addresses different mailboxes? ]

As distinct mailboxes, I think it would be within its rights to
do so.  I also think that, like the "user" and "UseR" local part
distinction, doing so would be fairly dumb and, if I were
implementing the MTA that <whatever> was going to use, I don't
think I'd go out of my way to make separating the two easy.

That's what I was thinking.  But I was also thinking it might be different 
from upper/lower case mailboxes since, there is a defined mapping betwen 
A-labels and U-labels, and we already have at least one place, DNS 
lookups, where the MTA has to turn one into the other.

I'm doing a project for the UASG testing the EAI conformance of a bunch of 
mail software.  It appears that Postfix treats A-label and U-label 
addresses differently, and Coremail may only accept the U-label and reject 
the A-label, although it's hard to tell because at the moment, its mail 
server for the 互联网.中国 domain doesn't accept anything.

Accoreding to my experiences, I think that Coremail accepts both U-label and 
I add Marvin Woo from coremail to join this discussion.

Best Regards
Jiankang Yao

MUA support leaves a lot to be desired, e.g. Roundcube webmail always 
turns the domain into A-labels, even if the mailbox is non-ASCII.



Coremail isn't accepting any mail at all for the 互联网.中国 domain. 
Telnet to port 25 and it says:

 554 IP<> is rejected: 0

Huh? What?
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