Fri, 19 Oct 1990 16:24:56 +0100
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>This week a big loop occurs between sunir.reunir.fr RFC987 gateway and
>the cyber-l somewhere in bitnet area.
Note the spelling with a dash.
>no one on this "CYBER_L" distribution list caring to check
Now with an underscore.
> Return-Path: <CYBER-L@HEARN>
Dash again.
> "MAIL FROM: <CYBER_L@HEARN>"
Underscore. It is very difficult for me to analyze this problem if I
cannot be sure whether we have an underscore or a dash here. LISTSERV
lets the list owner put whatever he wants in the "Sender:" field (which
the MTA uses to generate the MAIL FROM: field), and I can well imagine
why a list owner would want to have something that looks like the list
name but is still different, for instance CYBER_L instead of CYBER-L.
Checking the list headers now would prove nothing, the list might well
have been changed since then.
> this X400 receipient was unreacheble and the gateway send back
> a notification (call it an error-notification) to the address
> specified in the P1-"Expeditor" field, which is the same as
> "MAIL FROM...".
>
> And our X400 was right in doing this, YES IT was (and still
> is).
Yes, it is, but what does your delivery error look like? Some send what I
call "burps", ie a message saying just "There was an error processing
your mail." with a subject of "Warning: problem with DECNET host(s)"
(LISTSERV does trap these messages because it will never post the same
message to the list twice, but even to an experienced human reader there
is no way to know which of the N messages that were sent was rejected).
Note that I'm not saying your gateway generates "burps", I am just trying
to show that there is a whole gamut of delivery error types and that, for
this reason, including a copy of the delivery error in ANY loop
description is very important.
> 2) A liste such a CYBER_L, should not tolerate having
> mailer-daemon or Postmaster or ... talking in the list.
And what did your delivery error have in the 'From:' field? See above.
Your RFC excerpts show clearly that:
1. The system performing the final delivery should generate a Return-Path
field with the contents of the MAIL FROM: field.
2. The MAIL FROM: field is where you should send any nastygram.
Consequently it is correct for your gateway to send nastygrams to the
Return-Path address, assuming of course that it is generated properly.
What I fail to understand is how this is supposed to establish that
LISTSERV is "broken".
Finally, I would like to add that this problem occured with a LISTEARN
server. Unless the problem can be reproduced with LISTSERV or I can be
convinced that it would occur with LISTSERV, I do not want to spend time
discussing it. I am not saying that in order to get rid of a hot potato,
but because a lot of mailing-loop preventive code has been added since
the LISTSERV-LISTEARN split.
Eric
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