[Mailman-Users] query re "message has implicit destination"

Mark Sapiro msapiro at value.net
Thu Aug 31 01:22:56 CEST 2006

Bretton Vine wrote:

>I repeat, no criticism intended, I just need to be able to give a complete
>answer and am anticipating the questions I'll be asked. :-)

I think most of what I'm going to say here has been said by Dragon and
Brad already, but just for emphasis...

The major reason for require_explicit_destination is it helps filter
spam on an 'open' list (generic_nonmember_action = accept) and on a
closed list where the spammer might spoof a list member's address as
sender because much spam does not address the recipient directly.

The default setting in Defaults.py can be overridden by any site that
whishes the default for new lists to be No.

Whatever is chosen as the Defaults.py value for any particular list
setting, some will wish it had been the other way. It is simply not
possible to create "out of the box" defaults that will satisfy
everyone. That is why a site can change the defaults for itself and
individual lists can be changed to be different from the site defaults.

>In terms of the logs, the error is /exactly/ the same whether it's
> TO: list
> CC: someone
> TO: list
> BCC: someone
> TO: someone
> BCC: list
>Yes, I'm being pedantic -- but an explanation of the principle doesn't
>always answer what happens in practice. I know answers can't be sucked out
>of thin-air, but perhaps this has come up before?
>(or not and I need to look deeper)

What you are saying above is not correct.

require_explicit_destination means only that the list posting address
or one of the acceptable_aliases addresses must appear somewhere in a
To: or Cc: header of the post as received by Mailman. The presence of
a Cc: header or Bcc: header (which Mailman probably never sees). has
nothing to do with it.

Thus of your 3 examples above, if 'list' is the list posting address
that Mailman expects to see, only the 3rd example will be held for
implicit destination because in this and only this case, Mailman
doesn't see the list address as a recipient of the post.


To: someone
Cc: list

will also be accepted.

When the message is held for 'implicit destination', view the headers
of the message in the admindb interface and/or forward the post to
yourself, and you will see that what I'm saying is correct.

Mark Sapiro <msapiro at value.net>       The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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