On Wed, May 04, 2005 at 09:45:08PM +0200,
Markus Stumpf <maex-lists-email-ietf-smtp(_at_)Space(_dot_)Net> wrote
a message of 54 lines which said:
SMTP servers don't care about mail headers (**)
...
** There is one (valid?) exception I know of:
some MTAs looks at the number of Received: lines for the sake of loop
detection.
May be SMTP servers should not touch the headers. But they do (besides
the obvious of adding a Received header).
* Postfix checks the Delivered-To (loop detection).
* Most MTAs add Date, To and Message-Id if they are missing (may be
they should not, if only message submission and transfer were properly
separated...)
Unfortunately, the separation between 2821 and 2822 in the real world
is not as clear as we would like it to be.