[Mailman-Users] Attachments not getting through at random...

Mark Sapiro mark at msapiro.net
Tue Jun 23 03:19:29 CEST 2015

On 06/21/2015 10:55 AM, Nick Stevens via Mailman-Users wrote:
> Hi All,
> I'm new to the list - I did search the archives, but cannot find anything
> covering my specific case.

In the future and when following up, please post from your subscribed
(... at gmail.com) address, not ... at googlemail.com. Otherwise you run the
risk of your non-member post being discarded.

> My problem is with attachments to my list. For some users, attachments
> never get through. I'm sure it is not the file, in a couple of cases I
> asked the senders to CC my personal, email address. I was able to confirm
> the image was within limits, and also tried attaching it in a message from
> myself, which worked in every test.
> So I am somewhat confused as to what the problem might be, if it is not the
> attachment...

What are your list's Content filtering settings. If filter_content is
Yes, what's in filter_mime_types, pass_mime_types,
filter_filename_extensions and pass_filename_extensions, and what is the
mime type and filename if any of the attachments that don't get through?

Also, if collapse_alternatives is Yes, it is possible that the messages
have a MIME structure like


or something similar. I.e. a plain text alternative and a
multipart/related alternative with html and images or something similar.
collapse_alternatives will keep only the text/plain part.

If filter_content is No, then Mailman shouldn't be removing any
attachments, at least assuming Non-digest options -> scrub_nondigest is no.

> My sample size is fairly small, but I'm suspicious that Apple users are
> getting this problem preferentially.

Quite possible as Apple Mail is known to create 'unusual' MIME
structures. You may not be accepting some multipart subtypes that it uses.

> What might it be? Perhaps the encoding used?

Encoding shouldn't affect this.

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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