[Mailman-Users] Attachments AND no-attachments...

Mark Sapiro mark at msapiro.net
Thu Mar 10 20:20:43 CET 2011

Richard Troy wrote:
>In sum, it would be _fantastic_ if list subscribers have an
>option to receive or not receive attachments on a per-user basis, much as
>users can now elect to recieve digests. But, as that option doesn't appear
>to exist, I was thinking I could facilitate the same effect by using two
>lists - maybe three.
>The "obvious" thing seemed to be to create a second list for no
>attachments, have it filter out the attachments, and have the post-to
>address subscribed to the main list - with the reply-to also set, of
>course. This is VERY cumbersome, though, as the people on the no-attach
>list need to be authorized to post on the primary list, and visa versa
>because it wouldn't be welcome to lose the original poster's information
>from the mail header. ...It would be great if any subscribe / unsubscribe
>events could cascade to the other list, but the only way I found how to do
>that is to follow the basic direction on this page:

That information appears to have been copied from the FAQ at
<http://wiki.list.org/x/TIA9>. The FAQ has since been updated to
include information about the regular_include_lists feature in more
recent versions of Mailman. At first, I thought that would solve your
issue, but it won't because if for example, you put the no-attachments
list in regular_include_lists of the attachments list, a post to
attachments will go to the members of both lists, but all recipients
will get the attachments because the only content filtering applied
will be that of the attachments list.

So, moving on...

Why not have an attachments list and a no-attachments list with
completely disjoint membership. Make each list a member of the other.
This is not a problem because the X-BeenThere: headers will prevent

Also, put @attachments in the no-attachments list's
accept_these_nonmembers and vice versa so a member of either list can
post to either list. Also, put the attachments posting address in the
no-attachments list's acceptable_aliases and vice versa.

I don't think you need to mung Reply-To: at all.

Also, you might find the FAQ at <http://wiki.list.org/x/boA9> useful.

>Another issue has cropped up, too: I can't seem to get _any_ posts through
>with attachments intact! I think I've screwed the whole thing up with all
>the permutations in trying to get it working at all, that I'll have to
>drop the lists and start over. However, ANY insight into what it is
>exactly that's filtering out, for example, .jpg or .gif images, would be
>very welcome.

What gets filtered depends on content filtering. If you want to allow
anything on the attachments list, just set filter_content to No.

If you want to allow only jpeg and gif images and plain text and HTML
set pass_mime_types to


and set collapse_alternatives and convert_html_to_plaintext both to No.

If you are trying to do something else, please say specifically what?

If you are trying to understand how content filtering works, please try
to explain what part of the general description on the content
filtering page is unclear.

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

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