At 9:18 AM -0800 2/29/12, <ned+ietf-smtp(_at_)mrochek(_dot_)com> wrote:
Absent an extension, the MUA has no way of knowing if this parameter even
exists in the MSA, let alone how it is set.
Yes, exactly.
That's another reason why you need an extension - you absolutely do need a
parameter so that the MSA only does this stuff if the MSA requests it.
Yes, exactly.
I also think this is the wrong way for it to work. The problem with
this approach is that it forces the MSA to parse and modify headers,
and compare the addresses extract from those headers with the
various envelope addresses. That's inherently risky.
Yes, exactly.
It's much safer to have the MUA send a message without any of these
headers in
it and to have the MSA simply add the Bcc: field to message copies as needed.
This can be done with a BCC parameter on the RCPT TO:. The value of that
parameter can be the personal name phase to add to the address. This
way the only thing the MSA has to do is decode the parameter value,
concatentate some strings and add a header field containing the result.
Alternately, the value of the BCC parameter could be the entire Bcc: field
value. This would provide support for stuff like group constructs,
assuming we
want to allow that. (I can argue it either way.) This is even simpler because
now all the MSA has to do is decode the parameter and stuff it into a new
header field.
Two good approaches.
Remember, the target audience here has to be more than just a bunch of
geeks or this doesn't stand a chance of deploying.
Right.
The most useful thing, in my view, is a BCP on how MUAs should
generate messages with BCC recipients, and how MUAs should recognize
when a received message is a result of a BCC, and how to handle
replies etc. in such cases.
I'm intrigued by the behavior mentioned earlier of the originating
MUA mucking with the To and Cc header fields when sending a BCC
version, as an indication of this and to avoid unthinking
reply-to-all actions. I'm not sure I'm a huge fan of the "[To:]"
business, but enclosing the contents in parens to form a comment
might work.
--
Randall Gellens
Opinions are personal; facts are suspect; I speak for myself only
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Q: How many surrealists does it take to screw in a light bulb?
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