Bruce Lilly wrote:
This message serves a couple of purposes. When composed (within Mozilla
1.7), it included a Bcc field. Mozilla is configured to send to sendmail
listening on the submission port [the sendmail process happens to be
running on the same host as Mozilla in this instance]. Mozilla is also
configured to save a copy of sent messages in Mozilla format in a local
"folder". The Bcc copy should be sent by sendmail to a Cyrus IMAP
server (also running on the same host, as it happens) via LMTP. The
list should receive a copy w/o the Bcc field. Mozilla has little in
the way of configuration options for sending -- I'm not sure if it
checks Bccs and sends multiple messages via port 587, or if it relies
on the submission server to do that processing; but I intend to run
a traffic sniffer to find out, and I'll report anything significant
in a subsequent message.
Mozilla sent the message (once, with no Bcc header field) to the
MSA, with envelope recipients (RCPT TO) set to all of the recipients
specified, including bcc. The local Mozilla "Sent" "folder" copy
includes the Bcc field. The copy sent to the bcc address (and to the
list -- it was sent only once to the MSA -- does not include any Bcc
header field).
Regarding functionality discussed:
1. I-sent-a-bcc-to only appears in the local Mozilla "folder". It
therefore cannot be accessed (w/o some contortions and hoop-jumping)
anywhere else, or by any other MUA.
2. Bcc-should-be-sent-to is apparently how Mozilla uses the field
3. Why-you-got-this doesn't apply to the bcc recipient -- he has no
indication that the message was sent as a bcc.
4. Non-reply-to seems to be another Mozilla trait; if I go to the
local copy and try "Reply All", there's no copy sent to the bcc
address.
#1 and #3 are apparently disadvantages of the way this particular
combination of software operates. Sending separate Bcc and non-bcc
copies would be preferable functionally, but of course requires
additional bandwidth. The bandwidth issue could theoretically be
handled by offloading the "splitting" functionality on an MTA closer
to the Internet backbone, e.g. using an ESMTP extension as Jacob has
suggested.