txt file getting blocked as Quick Time file

Greg Matthews gmatt at nerc.ac.uk
Thu Oct 23 14:34:23 IST 2008

Kate Kleinschafer wrote:
> I am getting a few messages blocked saying they have a Quick Time file 
> attached (which shows as msg-18161-4.txt)

the quicktime signatures are extremely broad. I get around this by 
commenting out the overly generous signatures and re-compiling the magic 
data. See the man page for "file(1)" in particular the "-C" option. See 
also the man page for magic(5) although this is not necessary it will 
give you a better idea of how file works.

copy aside the orginal magic file (on redhat/centos this is 
/usr/share/file/magic) and edit it. Personally, I comment out the 
following lines:

#4      string          free            Apple QuickTime movie file (free)
#4      string          junk            Apple QuickTime movie file (junk)
#4      string          skip            Apple QuickTime movie file (skip)
#4      string          wide            Apple QuickTime movie file (wide)
#4      string          pict            Apple QuickTime movie file (pict)

which hit any message body beginning with those letters. If you examine 
the bodies of the messages that are getting blocked, I expect you'll 
find that they begin with one of those 4-letter combinations. Now 
recompile the .mgc file using file -C.

Finally exclude "file" from software updates (edit /etc/yum.conf or 
tweak your up2date config).

Also consider using the mime filetype checking - not sure where this is 
documented off-hand but it was discussed at length on this list.


> I know the message is ham.
> After doing some searching on the internet I came  across a thread that 
> said the following about the problem:
> /This bug is not so much a problem with filenames.  I'm just pointing out
> />/ that the filenames.conf entries don't override filetype.conf   So the
> />/ tnef created "msg*.txt" files that can be misinterpretted by 
> filetype as
> />/ Quicktime files can't be overridden.  The only options are to allow
> />/ quicktime filetypes or disable the "Use TNEF Contents" option.
> /Is the best option to allow QuickTime in filetype.rules.conf or is 
> there another more suitable option.
> Thanks
> Kate

Greg Matthews           01491 692445
Head of UNIX/Linux, iTSS Wallingford

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