--On Friday, 11 March, 2005 12:36 -0500 John Leslie
Tony Finch <dot(_at_)dotat(_dot_)at> wrote:
I'm proposing that the 2822 syntax should be extended to
allow arbitrary fields to be appended to the start of the
header, in a similar manner to Received: and Resent-* fields.
At first blush, this seems like a very good idea. There are
a number of things which are trace-like; and forcing them into
the non-trace area tends to confuse the ordering of the
OTOH, there _might_ be some existing MTA this would break,
though I can't think why...
What it breaks is at least one detector for bogus or fraudulent
mail. If the rules of 2821 are followed, then there is no
mechanism by which headers can be injected into a message other
than at the beginning, making a message with fields ordered as
a little dubious. Not nearly dubious enough, given the ways in
which things can be reordered, to reject or dump the message,
but perhaps worth a few points on an subjective probability
estimate that the message is at least partially faked.