Viktor Dukhovni:
> > You mean:
> >
> > Received: by MTA-NAME
> > Other headers added by the MTA named above.
> >
> > Versus:
> >
> > Other headers added by the MTA named below.
> > Received: by MTA-NAME
>
> Yes.
>
> > Postfix already appends From/Date/Message-ID under its own Received:
> > header. Placing Postfix's PREPEND headers under its own Received:
> > header is not inconsistent with that.
>
> Yes, but those are single-instance headers that pertain to the
> message as a whole, unlike trace information that pertains to a
> particular hop. Things like "X-Envelope-From" and various other
> prepends are typically hop-specific information, can be prepended
> multiple times, and their origin becomes ambiguous when placed
> below "Received" by some MTAs and above by others.
Pointer to RFC or best-practice document, please?
Some comments for historical accuracy:
- The access map PREPEND feature was implemented without much
consideration. I added Milter support years later, and obviously
did not consider the possibility that Postfix might already have
prepended lines above its own Received: header. I was only
reminded of that recently. Otherwise I would have changed PREPEND
years ago.
- The header_checks prepend action will prepend content in the
middle of the message header. That should be OK as long as it
does not add headers with names that appear in the DKIM signature.
As for the claim that Milters are supposed to see the on-the-wire
message, do you have a pointer to support that?
Wietse
