[imp] Re: "Return-Path" header?

[Chris Hastie]

On Mon, 20 Jan 2003, Michael M Slusarz <slusarz at bigworm.colorado.edu> 
wrote
>Quoting Liam Hoekenga <liamr at umich.edu>:
>
>| IMP doesn't seem to alter the original Return-Path when you bounce
>| mail, and that prevents message that are being sent to moderated groups
>| from being seen by anyone but the moderators.
>
>IMP is just trying to be RFC compliant - which can be all sorts of
>confusing.  From RFC 2822 [3.3.6]:
>
>   Resent fields SHOULD be added to any message that is reintroduced by
>   a user into the transport system. . . . **No other fields in the message
>   are changed when resent fields are added**.
>
>BUT, from RFC 2821 [4.4]:
>
>   The primary purpose of the Return-path is to designate the address to
>   which messages indicating non-delivery or other mail system failures
>   are to be sent.
>
Also from RFC 2821:

    It is sometimes difficult for an SMTP server to determine whether or
    not it is making final delivery since forwarding or other operations
    may occur after the message is accepted for delivery.  Consequently,
    any further (forwarding, gateway, or relay) systems MAY remove the
    return path and rebuild the MAIL command as needed to ensure that
    exactly one such line appears in a delivered message.


>It appears that we should strip out the existing Return-Path header since,
>obviously, we don't want these failure messages for example to go to the
>original sender.  However, this would violate a literal reading of RFC
>2822 - since NO other fields are supposed to be changed.
>
>I think I will go ahead and make the change, and if anyone else has an
>opinion on this, it would be great to hear.

I would be inclined to say strip out the Return-Path header, and use a 
MAIL FROM: that reflects the Imp account doing the redirecting. Final 
delivery of the original message has taken place successfully, there is 
no further need to send error reports to the original sender. Any 
failure to deliver the redirected message should be reported to the 
person who redirected it.
-- 
Chris Hastie