[EMAIL PROTECTED] (Peter Seebach) wrote:
>In message <[EMAIL PROTECTED]>, Neil W Rickert writes:
>>>I don't really object to it... but the Lsoft "listserv" mailing list package
>>>does. Whenever there's both a From: line *and* a "Sender:" line, listserv
>>>concludes that the Sender: line is authoritative.
>>What does "authoritative" mean here?
>It means that if my "Sender:" line says "[EMAIL PROTECTED]",
>that my mail will be rejected from a closed listserv list unless the address
>subscribed is "[EMAIL PROTECTED]". This makes it very hard
>to use a canonical address.
>>Quite apart from the "From:" header and any "Sender:" header, there
>>is the information transferred in the SMTP "MAIL From:" command,
>>typically referred to by email gurus as the "envelope sender". The
>>envelope sender is likely to be the same as is in the "Sender:"
>>header. It is more likely that the listserve package is using the
>>envelope sender than that it is using the "Sender:" header.
>Nope. I asked their tech support people. When they are evaluating whether
>a message came from a subscriber, if there is both a "From:" and a "Sender:",
>they assume that the Sender is more correct. I think this is wrong, but I
>seem to recall being told that their head developer is pretty much unwilling
>to grant the idea that, when people disagree about interpretation on an RFC,
>the best thing to do is adapt to allow their interpretations.
The principle is supposed to be that the "From:" header identifies
the author of the message, while the envelope sender or the "Sender:"
header identifies the person responsible for sending it. The mailing
list interpretation is actually a reasonable one. In principle it
allows you, as a subscribed user, to submit a message written by a
different author.
>>The ability to override this in nmh is a recognition that, in our
>>current complex world the value automatically determined on your
>>computer system might be invalid or inappropriate, due to the
>>complexity of today's email world, dynamic IP assignments, the use of
>>private hostnames on private networks that connect to Internet, etc.
>Yeah, the main problem is that it turns out to be useless data in almost
>all cases. In practice, when I send mail, it's always really me sending it,
>and the address I put in the From line is always really me, so the Sender
>line isn't all that useful.
It's actually more common to use the envelope sender, which often shows
up as "Return-Path:" in the final delivered message.
Right now, I am looking at your original message. It has your
address on the "From:" line. But the envelope sender address
is [EMAIL PROTECTED] Technically, that means that
you are responsible for the content of the message, and if I find
it libellous I should sue you. But [EMAIL PROTECTED] is
administratively responsible, and errors in delivery and other such
problems should be reported there.
This distinction between authorship and administrative responsibility
has turned out to be a very useful one, even if it happens to be
causing your problems right now.
>It would actually be a sort of cool tracking feature if it were something
>like X-Sender, but when it's Sender, a lot of mail programs conclude that
>it overrides From and Reply-To. (I have a lot of trouble with people on
>some Windows-based email package sending replies to my "Sender" address,
>too.)
Program that do that (prefer "Sender:" to "Reply-To:" or "From:" for
the purpose of replies) are badly broken. But that is not your
problem, which relates more to the distinction between administrative
responsibility and authorship.
-NWR
