Re: Attachments

1998-06-02 16:36:13
On June 2, 1998 at 15:06, Joe Salviz wrote:

Wow great software.  I just installed on my system and am very pleased.
I do have a problem with attachments that I can't seem to resolve. Excel
or Word documents that originated from either a PC or Mac seem to be
saved with names such as "bin003.bin".  However their names are
correctly displayed within the html document.

By default, MHonArc basis that actual filename by the content-type of
the attachment.  This determines the filename extension to use (so web
servers can send the proper content-type when transmitting to a
client).  The base name is computed by using the first 3 letters of the
extension followed by a number to where the filename is unique in the
directory it is written to.  However, the anchor link text for the
filename is either one of the following:  the value of
Content-Description, the specified filename (to show what the send
named the file), OR a general text description of the content-type.

This method is the default since it minimizes potential security
problems.  For example, if MHonArc by default uses the specified filename
as the filename to use, I could send a message with an attachment and
call it ".htaccess", or some other special file, that can give me
access priviledges that you do not intend.

This method is adequate for most users, but can be insufficient when
archiving messages that do not give the proper content-types for
attachments (the filename extension calculated from the content-type is
the critical component that tells web servers the type of data the file
is).  In your case, the attachment should be labeled as an Excel
document, but it is actually labeled as binary data
(application/octet-stream).  This is the fault of the mail composer
software used by the sender.

Possible solutions to the problem:

    o   Leave things as-is, and inform senders of such messages to
        label properly attachments they send.  BTW, doing this is good
        to do regardless of what you choose to do.  People, and the
        software they use, should know how to do things right.  Leaving
        binXXXXX.bin files will cause an inconvience to readers, but
        you will not compromise your server/system.

    o   Activate the "usename" option to the external file filter.
        Details are in the MIMEFILTERS (Default Settings section) and
        MIMEARGS resource pages.  Warnings are given about the security
        implications of "usename".  In sum, "usename" will cause the
        filename specified in the message to be used.  Also look at
        the "subdir" option.

Hope this helps,


             Earl Hood              | University of California: Irvine
      ehood(_at_)medusa(_dot_)acs(_dot_)uci(_dot_)edu      |      Electronic 
Loiterer | Dabbler of SGML/WWW/Perl/MIME

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