Provided by: mimedefang_2.53-1_i386 bug

NAME

       mimedefang - Sendmail MIME mail filter

SYNOPSIS

       mimedefang -p connection -m mx_socket_name -U user [options]

DESCRIPTION

       mimedefang is a filter built around Sendmail 8.11’s milter API for mail
       filters.  It collects each incoming message and runs a  filter  on  the
       message.   This  is  useful  for  deleting  attachments  which may be a
       security risk on poorly-designed systems like Microsoft Windows.

       mimedefang  does  not  actually  run  the  Perl  filter;  instead,   it
       communicates  with  mimedefang-multiplexor(8),  which manages a pool of
       persistent Perl processes.  See the mimedefang-multiplexor man page for
       additional information.

OPTIONS

       -U user
              Runs  mimedefang  as  user  rather than root.  The user argument
              must match the argument to mimedefang-multiplexor’s -U option as
              well.

       -p connection
              The  -p  switch  is required and specifies the milter connection
              type.  Typically, you should run mimedefang on the same computer
              as sendmail.  Therefore, you should use a UNIX-domain socket for
              the connection type.  The suggested value for the -p  switch  is
              /var/spool/MIMEDefang/mimedefang.sock.

       -m mx_socket_name
              Specifies   the   socket   for  communicating  with  mimedefang-
              multiplexor(8).  The mx_socket_name specifies the  path  of  the
              UNIX-domain  socket.  See mimedefang-multiplexor(8) for details.

       -b backlog
              Sets the "backlog" argument to  the  listen(2)  system  call  to
              backlog.   If  this option is omitted, then the operating-system
              default backlog is used.

       -d     The -d switch causes mimedefang  not  to  delete  the  temporary
              spool  files  it  creates  for  incoming  messages.  This is for
              debugging purposes only and should never be used on a production
              mail server.

       -r     Causes mimedefang to perform a relay check before processing the
              message body.  It  calls  into  a  user-supplied  Perl  function
              called  filter_relay  with  the  IP address and host name of the
              sending relay.  (See mimedefang-filter(5)  for  details.)   This
              flag only takes effect if the -m flag is used also.

       -s     Causes  mimedefang  to  perform a sender check before processing
              the message body.  It calls into a user-supplied  Perl  function
              called  filter_sender  with  the envelope address of the sender.
              (See mimedefang-filter(5) for details.)  This  flag  only  takes
              effect if the -m flag is used also.

       -t     Causes  mimedefang to perform recipient checks before processing
              the message body.  It calls into a user-supplied  Perl  function
              called  filter_recipient  with  the  envelope  address  of  each
              recipient.  (See mimedefang-filter(5) for details.)   This  flag
              only takes effect if the -m flag is used also.

       -q     Permits  the  multiplexor  to  queue  new  connections.  See the
              section QUEUEING  REQUESTS  in  the  mimedefang-multiplexor  man
              page.

       -k     Causes  mimedefang not to delete working directories if a filter
              fails.  This lets you obtain the message which caused the filter
              to  fail  and  determine  what  went wrong.  mimedefang logs the
              directory containing the failed message using syslog.

       -P fileName
              Causes mimedefang to write  its  process-ID  (after  becoming  a
              daemon) to the specified file.

       -C     Conserve file descriptors by opening and closing disk files more
              often.   (Disk  files  are  never  held   open   across   Milter
              callbacks.)   While  this  shortens  the  length  of time a file
              descriptor is open, it also leaves more  opportunities  for  the
              open  to  fail.  We do not recommend the use of this flag except
              on very busy systems that exhibit failures due to a shortage  of
              file descriptors.

       -T     Causes  mimedefang  to log the run-time of the Perl filter using
              syslog.

       -x string
              Add string as the content of the X-Scanned-By: header.   If  you
              set  string to the empty string (i.e. -x ""), then no X-Scanned-
              By: header will be added.

       -X     Do not add an X-Scanned-By: header.  Specifying -X is equivalent
              to specifying -x "".

       -D     Do  not  fork into the background and become a daemon.  Instead,
              stay in the foreground.  Useful mainly for debugging or  if  you
              have a supervisory process managing mimedefang.

       -M     When  mimedefang  processes  a  message,  it creates a temporary
              working directory.  On some architectures,  you  might  have  to
              protect  this  action  with  a "mutex" to stop different threads
              from interfering with each other.  This should not  normally  be
              necessary, but if you see many logs that mimedefang is unable to
              create the working directory, use the -M flag.

       -S facility
              Specifies the syslog facility for log messages.  The default  is
              mail.   See  openlog(3) for a list of valid facilities.  You can
              use either the short name ("mail") or long name ("LOG_MAIL") for
              the facility name.

       -a macro
              Pass  the  value  of the specified Sendmail macro through to the
              Perl filter.  You can repeat the -a option to write more  macros
              than  the  built-in  defaults.   Note that in addition to asking
              mimedefang to pass the macro  value  to  the  filter,  you  must
              configure Sendmail to pass the macro through to mimedefang using
              the  confMILTER_MACROS_ENVFROM  definition  in   Sendmail’s   m4
              configuration file.

       -h     Print usage information and exit.

OPERATION

       When  mimedefang  starts, it connects to sendmail using the milter API.
       (See the Sendmail 8.11  documentation.)   For  each  incoming  message,
       mimedefang  creates  a temporary directory and saves information in the
       directory.  When the end of message is  received,  mimedefang  executes
       the following command:

            /usr/bin/perl /usr/local/bin/mimedefang.pl dir

       (Substitute   the  appropriate  paths  on  your  system  for  perl  and
       mimedefang.pl.)  The single argument dir is the temporary directory  in
       which the message information has been saved.

       (If  you  are  using  mimedefang-multiplexor, the multiplexor manages a
       pool of persistent Perl processes, and mimedefang itself does not start
       a Perl interpreter.)

       When  the  Perl  script  is  started,  the temporary directory contains
       certain files; details of the communication protocol between mimedefang
       and the Perl script are in mimedefang-protocol(7).

WARNINGS

       mimedefang  does  violence  to  the flow of e-mail.  The Perl filter is
       quite picky and assumes that  MIME  e-mail  messages  are  well-formed.
       While  I  have  tried to make the script safe, I take no responsibility
       for lost or mangled e-mail messages or any security holes  this  script
       may introduce.

       Spawning  a  Perl  process  for  each  incoming  piece  of SMTP mail is
       expensive.  mimedefang may overload a busy mail server unless  you  use
       the multiplexor.

AUTHOR

       mimedefang was written by David F. Skoll <dfs@roaringpenguin.com>.  The
       mimedefang home page is http://www.mimedefang.org/.

SEE ALSO

       mimedefang.pl(8),   mimedefang-filter(5),    mimedefang-multiplexor(8),
       mimedefang-protocol(7)