At 20:06 +0200 on 04/02/2007, Frank Ellermann wrote about Re: More
references in 2821bis:
Robert A. Rosenberg wrote:
[Apparently-To]
I seem to remember that it ALSO needed the absence of a Cc header
to trigger this injected listing.
Plausible, maybe RFC 2076 just didn't mention this detail. RFC 2821
7.2 doesn't discuss any details, and RFC 3552 6.1.1.2 is only a copy
of RFC 2821 7.2.
Somebody on the EAI list got me to dig out a stoneage bat book, with
that at hand I find:
<time travel=1994>
| If the header of a mail message lacks all recipient information
| (lacks all of the To:, Cc:, Bcc: header lines), sendmail adds an
| Apparently-To: header line and puts the recipient's address in
| from the envelope into the field of that line. This behaviour
| is hardcoded into sendmail.
|
| The Apparently-To header name is not defined in RFC822. It is
| added by sendmail because RFC822 requires at least one To: or Cc:
| header, and neither is present.
</time>
Trying to fix missing header fields by adding a different header
field was a rather odd idea... <g> And "apparently" it did not an
Apparently-To when there was (only) a Bcc, but it stripped the Bcc,
again arriving at no RFC822 recipient at all. Oh well... And I'll
fix my header field name review request, thanks for your hint.
Frank
You're welcome. I tend to be a nit-picker and tend to want to see
details of this type accurate.
My memory that a Cc would suppress the injection of the header, seems
to be borne out by that quote above. As to the Bcc, it was/is
normally never sent by the MUA (although some did, if I remember) but
was only used to Mail-To list that was passed on by the MUA.