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Re: [Q] mail to me AND the list to BOTH places..

1996-12-16 10:12:33
Stan Ryckman <stanr(_at_)sunspot(_dot_)tiac(_dot_)net> writes:
Rick Troxel wrote:

On Wed, 11 Dec 1996, Philip Guenther wrote:

guenther> I have found that when sorting out mail from mailing lists
guenther> into separate folders/mailboxes/whatever, the *best* (opinion
guenther> alert!) thing to 'sort' on is the Return-Path: header.  Any
guenther> mailing list set up this decade will send out messages with an
guenther> envelope sender of something like: 
guenther> 
guenther>    procmail-request(_at_)Informatik(_dot_)RWTH-Aachen(_dot_)DE
guenther> 
guenther> Most (?) MTAs, and sendmail in particular, will put the
guenther> envelope sender in the Return-Path: header, where it can be
guenther> matched on. 

I find that very few of the lists to which I subscribe have this header. 
I've had to develop my personal criteria on a per list basis. 

Even *THIS* (procmail) list arrives here without a "Return-Path:"
header (you meant "header field" I know).  Was it set up in this
decade?  BTW, they use sendmail here I'm 99% sure.

I never said that modern lists insert a Return-Path: header; rather,
I said they changed the envelope sender to an 'administrative' address.
This list does do that.  Whether or not a "Return-Path:" header is present
is dependent on the MTA that does final delivery, i.e., _yours_!


...
I've found that if you have access to "From ", it's the most consistent
for *ALL* types of lists.  If you can count on "Return-Path:", that
may work for you -- but it's probably bad advice to give, since it seems
to be common not to supply it (I have three accounts, none of which
supply that header field except when it's a *local* return path).


The address you see in the "From " header should always be the same as
what appears in the Return-Path: header (when present).  They're both
coming from the envelope sender, see rfc1123 section 5.2.8 for
details.  One is (hopefully) inserted by sendmail, the other is
inserted by the MDA which is passed it by sendmail via a '-f' (or maybe
a '-r') command line argument.


The key advice I was trying to give is that sorting/refiling based on
the envelope sender is a Good Thing.  I should have mentioned that it
is an "implementation detail" whether you do this by matching on the
"From " pseudo-header or on the Return-Path: header, but, well, I'm not
perfect.  I'll agree that the Return-Path: header is optional according
to the rfcs.  However, it is quite common from the people I've talked
to, and sendmail version 8 configs, as shipped, put it in on local
delivery, so I'm sorta surprised that you haven't see it more.  I'll
note that putting it in _only_ when it's local makes no sense to me, so
I'll just express mild skepticism with regards to this.



I'll argue against using "Return-Path:" unless you want to depend on
information supplied (or not) at the last stage of transport, rather
than by the mailing list itself.  Thus, I agree with Rick and
disagree with Philip (from whom I've learned lots though).

You *always* are depending on both, period.  Or do you think the
"From " header was inserted by the mailing list?

(Thanks for the compliment though.)

Philip Guenther

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