[Mailman-Users] Attachments

Mark Sapiro msapiro at value.net
Sat Sep 4 17:04:01 CEST 2004

Bob Escher wrote:
>How do I allow attachments and html
>to be allowed through?
>Last week we had a list member send pdf
>and they did get through.
>Or if someone does a nice document in Word
>with graphics how can it be allowed to go through
>with everything intact

I suggest you look at
  http://www.birdhouse.org/etc/evilmail.html and

These documents point out among other things that not everyone has the
same software, not everyone wants or is able to read arbitrary
attachments, and MS-Word is a particularly bad choice of format to use
to exchange formatted text.

If you still want to allow MS-Word and other attachments on your list,
recognize that the two reasons they don't go through are maximum
message size and content filtering. Your max message size must be
sufficient to accept the messages you want. Since most attachments
will be base64 encoded and base64 encoding requires a little more than
4 message bytes to represent each 3 bytes of the attachment, your max
message size needs to be about 1.4 times the size of the largest
attachment you expect plus enough extra to allow for the headers, text
and possibly HTML that goes with it.

Then you either have to be sure content filtering is off or adjusted to
accept the content-types you want to allow.

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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