Files being blocked despite configuration changes

Julian Field MailScanner at
Wed Jul 8 09:00:05 IST 2009

On 08/07/2009 00:06, Glenn Steen wrote:
> 2009/7/6 Kaplan, Andrew H.<AHKAPLAN at>:
>> Hi there --
>> Thanks for your reply, and my apologies for not getting back you sooner. I was
>> on vacation last week. I had a question on how would I go about implementing
> Hi Andrew,
> I'm on a rather less that relaxing vacation myself (helping a relative
> repanel&paint a rather huge economy building (double garage, old
> carpentry shop (kind of late 19-th centuy design), wood shed, etc
> etc... The darned thing measures about 25x8 meters and is about 10 m
> high)), so ... I'll try shift from hammers and nails to MS:-)
>> your
>> suggested "file -i" method. Would it be simply a matter of adding an argument
>> to the /etc/init.d/MailScanner and/or /etc/sysconfig/MailScanner files, or is
>> there another suggested method?
> All you should need do, IIRC is to change the File Command setting in
> MailScanner.conf, and perhaps look at/amend a few things in the
> filetype.rules conf file (don't remember exactly). Some find that the
> shift to mimetype detection become a bit too permissive (letting some
> executables past...), so you should test it as thoroughly as possible.
> Rather recently some kind soul posted a diff, to this list, for
> removing the troublesome one-byte magics... That you might be able to
> use, instead of switching to file -i.
You shouldn't have to edit anything except filetype.rules.conf, MIME 
type detection is already built into that, just read the comments at the 
top of that file.
>> -----Original Message-----
>> From: mailscanner-bounces at
>> [mailto:mailscanner-bounces at] On Behalf Of Glenn Steen
>> Sent: Saturday, June 27, 2009 6:54 PM
>> To: MailScanner discussion
>> Subject: Re: Files being blocked despite configuration changes
>> 2009/6/26 Kaplan, Andrew H.<AHKAPLAN at>:
>>> Hi there --
>>> I received a request to have .dat files be allowed through our mail server.
>>> Files of this type
>>> were normally sent to quarantine with an e-mail notification report stating
>>> the following:
>>> Report: MailScanner: No programs allowed (set.dat)
>>> Report: MailScanner: No programs allowed (set.dat)
>>> I reconfigured the filename.rules.conf and filetype.rules.conf files to
>>> allow the above file
>>> types to pass through without problem. Listed below are the syntaxes from
>>> each of the
>>> configuration files:
>>> filename.rules.conf
>>> # Physics has requested that files of this type be allowed...
>>> allow   \.dat$
>>> filetype.rules.conf
>>> allow   dat             -                       Physics requested these be
>>> allowed
>>> Once these changes were made, MailScanner along with the mailserver,
>>> Sendmail, were
>>> restarted via the /etc/init.d/MailScanner script. There were no failed
>>> messages appearing
>>> on-screen when this occurred.
>>> The problem is the following: even though the files in question have been
>>> configured to
>>> be allowed, they are still being blocked and sent to quarantine. The version
>>> of MailScanner
>>> is 4.72.5 while that of Sendmail is 8.14.1.
>>> What other steps and/or
>>> corrections do I need to make in order to fix this? Thanks.
>> The file command doesn't know what "dat" is... It finds the "magic"
>> strings/bytes that identify it as some type of executable (just run
>> file on the quarantined file, if you store them, and you'll see). This
>> might be due to the file actually being an executable, or accidentally
>> triggering one of the more optimistic one-byte-magics ... in which
>> case you either face editing/recompiling your magic file, or switching
>> to "file -i" for file type purposes. The latter might be best.
>> Cheers
> Cheers


Julian Field MEng CITP CEng
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