> Quoth Rufus evison on Fri, Sep 11, 1998:
> > How can I allow a user to set the return path on outgoing mail. My
> > problem is that many of the cgi scripts on our web server send mails.
> > They all run as the same user (www) and sometimes the address they send to
> > is duff, or the size of the message is too big for the recipient, or some
> > similare problem.
>
> You can make www "trusted" user and let it set the envelope "From ".
> Read RFC 822. Return-Path is a header which is to be added at
> the final delivery, based on Envelope "From ".
I wouldn't do that if the users can install their own cgi scripts.
It would be tantamount to making all of those users trusted...
Try adding an Errors-To: header. You should also set the Reply-To:
in case any of the recipients actually try to reply. NOTE that if
the cgi script already set either of these headers, you should
probably leave it instead of adding you own version.
Most unix MTAs will honor the Errors-To: header; but some MTAs on
other systems don't really play well in the RFC822 world and may
insist on using the envelope from address instead. In this case,
the easiest thing to do is to set up a filter for user 'www' that
detects bounce messages and forwards them appropriately. (By
examining the bounced message headers for Errors-To: and Reply-To:
headers.)
If you expect no legitimate mail addressed to www, you can
assume that all messages coming to that address are errors.
Otherwise, you'll have to try to automatically recognize them.
Bounce messages are theoretically simple - they should have an
envelope from address of '<>' (this is to prevent bounce loops
if the bounce message can't be delivered.) But again, some
(mostly non-unix) mailers aren't compliant. So messages which
aren't caught by that test will need to be examined for other
clues. They will often have other easily recognizable values
in either envelope from or From: headers; or certain key phrases
in the Subject:
-Pat
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