From: Jon Kyme [mailto:jrk(_at_)merseymail(_dot_)com]
Sent: Monday, April 19, 2004 1:12 AM
To: Harry Katz
Subject: Re: A proposal on identities
BTW, it's come to our attention that some MTAs today insert
headers in the message whenever they forward mail. Postfix
apparently insert a header called Delivered-To and exim inserts an
Envelope-To header. Although these headers are not defined
they seem to be in fairly widespread use. We could consider adding
them to the list of headers in step 2, after Resent-From
and before Sender.
FYI, a default Exim configuration DOES NOT add an Envelope-To
header, and will (by default) remove it if present, since
this header should not be present in messages in transit.
8 ) I'm sure you could consider any header added by
mis-configured and home-rolled MTA in your scheme, but I'm
not sure how useful that would be.
Thanks for the correction. This is indeed not on by default in Exim.
However, my understanding is that the header, if turned on, is preserved
if the message is forwarded due to a .forward file.
No, I believe that you've misunderstood. Exim's "redirect" router (which is
a common way of handling .forward files), may generate a new address which
is passed on to its transports in the normal way. The default behaviour of
the transports is to remove any Envelope-To header. Exim may be configured
to use a separate MDA (e.g. procmail) and this may preserve the header, in
which case, I'd count this as a misconfiguration. Which was my point: A
misconfigured MTA may emit messages containing any arbitrary string in the