[Mailman-Users] Digests and HTML-enhanced email

Anne Wainwright anotheranne at fables.co.za
Sat Oct 22 17:13:56 CEST 2011

Dear Lindsay,

perhaps I can make an input to this thread since I was about to
post something similar. If my comments are incorrect, please advise
since I have no desire to mislead any one.

We, too, have a load of old dinosaurs on one list who always manage to
post to wrong addresses and whose posts are of often rejected.
Getting the plain-text gospel across is hard.

Outside of digests, of which I know nothing, I see two approaches.
One aimed at getting plain text conformity from member input and the
other at getting plain text readability from Mailman output.

The first is reflected in the users FAQ 3.10 "How to enforce a
text-plain policy". The answer being "with difficulty" because this
option probably (as I read it) ensures that any message with
non-plain-text content is completely, utterly, and totally, rejected,
even if plain-text is present, rejecting all non-conformist messages and
requiring you to drill your recipients into plain-text submission.

The second is Content Filtering. I understand that this is to remove
objectionable content types, and steamroller the rest into conformity as
plain-text. It appears not to be 'on' by default.

With a number of lists running I had played about with these items, but
we have a residual core of trouble. I have just (read last night)
reverted to switching Content Filtering 'on' with the default settings
and will monitor results closely. The lists are now set identically
in this regard. Text-plain enforcement policies are not in place at


On Fri, 21 Oct 2011 23:21:09 -0500
Lindsay Haisley <fmouse-mailman at fmp.com> wrote:

> I host a list for about 700 autoharp musical enthusiasts on Mailman
> 2.1.12.  The subscribers are by and large somewhat elderly and non
> techie, and to most of them an explanation of the difference between
> HTML-enhanced email and plain text email would be unintelligible
> geek-speak.  I recently received the following email from one of the
> subscribers:
> > "Scrubbed" messages as they appear in my cyberpluckers DIGESTS:
> > This type of problem is perhaps a bit over 6 months old, and evidently
> > is caused by the manner in which some people have tried to attach
> > their message to their cyberplucker posting.
> > 
> > How can this problem be resolved?    THANKS ... Drew Smith
> > *******************************************************
> > 
> > Message: 25
> > Date: Fri, 7 Oct 2011 08:42:29 -0700
> > From: "foo bar" <.......>
> > To: Cyberpluckers at autoharp.org
> > Subject: Re: [CP] Intro
> > Message-ID: <a0ffed34-525e-40a5-88c6-4b78dbef2df8 at blur>
> > Content-Type: text/plain; charset="us-ascii"
> > 
> > An HTML attachment was scrubbed...
> > URL:
> > http://www.autoharp.org/mailman/blah/blah/..../attachment.html
> >
> > ... <snip> ... other examples
> I took a look at the list archive and indeed the email appears in the
> archives also with only a link to the attachment, which is the
> HTML-enhanced message, visible as HTML code.  There's no plain text
> version in the archive.
> I explained to the subscriber, and to the list admins, that this (and
> similar) posts were probably HTML-only posts, and that, absent a plain
> text rendering in a multipart email, the list server had no way to
> generate a plain text version, and that including multiple HTML-enhanced
> emails in a digest was problematic and not going to work very well, if
> at all.  The list admins are aware that plain text is the appropriate
> format for posting to a mailing list, but subscribers come and go from
> this list, and as I said, many don't understand such things, and it
> seems that there are a number of mail programs out there which will
> generate an HTML-enhanced email without an accompanying MIME text/plain
> version.
> The list is configured with mime_is_default_digest set to MIME, which I
> assume sends digests with each post as a separate attachment (I've never
> subscribed to the digest for this list, so I don't really know).  I had
> assumed that this might address this problem, but apparently not.
> One of two things needs to happen.  Either the list server should refuse
> and bounce posts with no MIME text/plain part, or some more intelligent
> configuration of Mailman needs to be available so that posts within a
> digest will render properly under these circumstances.  Maybe a more
> recent version of Mailman can do this, I don't know.  Any suggestions
> would be appreciated.
> I rather dislike HTML-enhanced email (to put it gently).  There's no
> fixed standard for it, and what renders one way in one mail reader
> renders some other way in another mail reader, and it confuses the hell
> out of list servers.  But people will use it, increasingly it seems, and
> insist on doing so, so somehow this kind of problem needs to be dealt
> with.

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