Processed-By (or Transmitted-By) header concept

I also started working on draft that tries to deal with a problem that
when email message passes through forwarders, email lists and other
similar systems those systems make changes to important email headers
and to envelope and its difficult to tell at later time what changes
they have made (or if these changes happened at all) and who is to be 
considered responsible for making these changes.

The concept introduces new header "Processed-By" (alternative name
"Transmitted-By", let me know which name you like better) and this
header is to be used to list name of the system making changes to
email message, email address of responsible party and list of
headers that are being changed. Together with it introduced are
Original-???? headers which are to be used to preserve original
values of the headers that are being changed. For RFC2821 envelope
parameters that are changed Original-Envelope-??? headers can be used.
Additionally "New-????" headers maybe used to list how these headers
were changed (this is intended primarily for RFC2821 envelope data).

It is intended that Processed-By header would be added by any
system that is changing destination of email message or its source.

Below I'm going to give some example of how these header might
be used by forwarders and by email lists, etc:

----------------------------------------------------------------------
1. Mail List (changes to envelope and to header to and sender):

Processed-By: odin.ietf.org (ip=[132.151.1.176])
  on-behalf-of [email protected]
  changes-to List-ID,Sender,CC,
    Envelope-Recepient,Envelope-ReturnPath,Envelope-Submitter
  process-type maillist (list-id=<ietf.ietf.org>) ; 
New-Envelope-Recepient: [email protected]
New-Envelope-ReturnPath: [email protected]
New-Envelope-Submitter: [email protected]
Original-Envelope-Recepient: [email protected]
Original-Envelope-ReturnPath: [email protected]
Original-Envelope-Submitter: [email protected]
Original-To: [email protected]
Original-Sender: [email protected]

2. Forwarding system that does not change RFC2821 Mail From

Processed-By: mail.forwader-example.com (ip=[10.0.0.10])
  on-behalf-of [email protected]
  changes-to Envelope-Recepient,Envelope-Submitter
  process-type forwarding
New-Envelope-Recepient: [email protected]
New-Envelope-Submitter: [email protected]
Original-Envelope-Recepient: [email protected]
Original-Envelope-Submitter: [email protected]


3. An outgoing SMTP proxy system that sits in the hotel and is to
   be used by all guests (sets Sender header and RFC2821 submitter)

Processed-By: proxy.hotel-example.com (ip=[10.0.0.10])
  on-behalf-of [email protected]
  changes-to Sender,Envelope-Submitter
  process-type smtp-proxy
New-Envelope-Submitter: [email protected]
Original-Envelope-Submitter: [email protected]
Original-Sender: [email protected]
----------------------------------------------------------------------

Please let me know what you think of this concept and if you think it
would be usefull and send me your comments and suggestions. And I do
expect to have draft available describing this within one or two weeks.

---
William Leibzon, Elan Networks:
 mailto: [email protected]
Anti-Spam Research Worksite:
 http://www.elan.net/~william/asrg/