restricing few users from sending/receiving attachments in postfix and in sendmail

[Les Mikesell]

On Mon, 2006-01-23 at 09:57, Tim wrote:
> On Sun, 2006-01-22 at 17:12 +0000, Paul Howarth wrote:
> > My point was that it's virtually impossible to do this because
> > attachments can be split up into multiple emails (thus getting around
> > size restrictions) and can be included in (say) uuencode format in the
> > message body rather than using a MIME-style attachment.
> 
> I don't see why a filter can't strip out attachments done either way.
> If one can parse MIME headers, one can also parse for UUE beginning and
> end markers.  Multipart messages can also be checked for, but even if
> not, catching the beginning and end of a multi-part would kill most data
> fairly well.

On the sendmail side, using MimeDefang as a milter would be a
good place to start.  The default setup includes a set of
'bad' filename extensions (things windows boxes will
automatically execute) and code to strip them.  The actions
are controlled by a snippet of perl that you can easily
change to do whatever you want.

-- 
  Les Mikesell
   lesmikesell at gmail.com