Re: BCC not working?

[Brian Stafford <brian stafford uklinux net>]

On 2001.05.18 17:28:59 +0100 Carlos Morgado wrote:

> The Bcc: is done by the mua aplying the same DATA to a message
> with RCPT TO: equal to the bcc line. Bcc: should not be placed 
> in the message headers by the mua.

> the mta does not care for 
> anything not in the RCPT TO: line. (correct brian?)

Correct: the MTA may only send a message to the recipients listed in
RCPT commands.  These recipients may be entirely unrelated to those
listed in the headers, a mailing list or alias expansion is an
example of this.

> just to clarify has there seems to be a lot of confusion between
> smtp commands, mail headers, mail bodys and data.

There seems to be.  Envelope normally refers to data in the SMTP
session, i.e. sender in the MAIL FROM: command and recipients
in RCPT TO: commands.  The envelope does not distunguish types
of recipient.

Headers refer to the structured data at the start of the message
i.e. Name: value lines.  Note that header lines starting with a space
are continuation lines.
Different headers are used to distinguish categories of recipient,
i.e. To/Cc/Bcc.

The body is the bit that comes after the blank line terminating the
headers.  Ignoring issues regarding MIME encoding, an MTA cannot
process the message body in any way since it cannot understand the
content of the message intended for human consumption.

> > Only for the recipients *not* listed in the bcc: header.  The
> recipients
> > listed in the Bcc header would get a second version of the message
> > with the Bcc header intact.
> > 
> or not. kind of depends.

Yep.  A lazy implementation is just not to put a Bcc header in at all
and I suspect a lot of MUAs do this.  But the Bcc header implemented
correctly can carry useful information I feel.

> that's nice to happen and sounds the Right 
> way to do it but i've received messages from less enlightned muas that
> just send 1 message to everybody. prolly to save bandwith while sending
> those wonderfull 5M ms attachments (did i blame MS ? oh my :))

That's the disadvantage - a huge message which is Bcc'ed.
Suggests the need for an option to control the Bcc behaviour.
Theres three possibilities.
1) No Bcc header at all.
2) An empty Bcc: header sent to Bcc: recipients only
3) A Bcc header listing Bcc recipients sent to Bcc recipients only

Perhaps balsa should implement a fourth category of recipient, like Bcc
but *never* listed in a header.

Regards, Brian