The owner of one of the Mailman mailing lists I administer recently
asked me to add an important footer to the bottom of every message sent
out to the list.
I added the footer to the list's configuration, but shortly afterwards,
he complained to me that he was not seeing it in messages sent to the list.
This, of course, was the result of the problem that is often reported
here, i.e., that Mailman adds the footer as a separate part of multipart
MIME messages, and although the footer is marked for inline content
disposition, many email clients (most notably Outlook) fail to display
it inline, and instead display it as a text attachment to the message.
This problem is described in detail on the Mailman Wiki
<http://wiki.list.org/pages/viewpage.action?pageId@30707>. There is a
link there to a solution
submitted to the Mailman developers for consideration over five years
ago, but unfortunately they rejected it and the patches are stale and
incompatible with the current stable Mailman version.
When this problem is brought up on this list and elsewhere, people often
mention that a tool such as mimedefang could be used to solve it.
That's true, but nobody ever seems to provide the details of exactly how
to do it. That's probably because it isn't obvious.
I've just finished implementing a generic solution that will work
out-of-the-box with standard versions of mimedefang and Mailman and only
requires you to edit your mimedefang filter configuration once -- after
that, you can enable this solution merely by editing the configuration
of a Mailman list to add some special tokens to the footer setting to
tell mimedefang to do the right thing.
You can read the documentation of my solution here
<http://stuff.mit.edu/%7Ejik/software/mailman_mimedefang/> or download
I love to hear from people who are using my software, so please email me
and let me know if you find it useful. Please also email me if you have
any questions, suggestions, bug reports, fixes or enhancements to share.