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SLATTACH(8)               BSD System Manager's Manual              SLATTACH(8)

     slattach -- attach serial lines as network interfaces

     slattach [-a] [-c] [-e exit-command] [-f] [-h] [-l] [-n] [-z] [-L]
              [-r redial-command] [-s baudrate] [-u unit-command]
              [-K keepalive] [-O outfill] [-S unit] ttyname

     The slattach utility is used to assign a tty line to a network interface,
     and to define the network source and destination addresses.

     The following options are available:

     -a      Autoenable the VJ header compression option, if the other end of
             the link is capable of VJ header compression then it will be used
             otherwise normal headers will be used.

     -c      Enable the VJ header compression option.  Note that both ends of
             the link must be able to use VJ header compression for this to

     -e exit-command
             Specify a command to be invoked within a shell 'sh -c
             exit-command' before slattach exits.

     -f      Disable the invocation of daemon() to run slattach in the back-

     -h      Turn on cts/rts style flow control on the slip port, by default
             no flow control is done.

     -l      Disable modem control (CLOCAL) and ignore carrier detect on the
             slip port.  By default the redial-command is invoked upon carrier
             drop and slattach aborts if no redial-command is specified.

     -n      Throw away ICMP packets.  The slip interface will ignore ICMP
             packets to prevent slow lines being saturated by ICMP responses.

     -r redial-command
             Specify a command to be invoked within a shell 'sh -c
             redial-command' whenever carrier is lost on the modem line.
             Empty redial-command (i.e. -r "") cause connection reestablishing
             on leased line without any external command invoked.

     -s baudrate
             Specify the speed of the connection.  If not specified, the
             default of 9600 is used.

     -u unit-command
             When the line is switched to slip discipline, run ``sh -c
             unit-command old new'' where old and new are the slip unit num-
             bers when the line was last opened and the unit number of the
             current slip connection respectively.  The unit number can change
             after redialing if you are using more than one slip line.  When
             slattach is connected for the first time, ``sh -c unit-command -1
             new'' is run.  When slattach is disconnected, ``sh -c
             unit-command old -1'' is run.  The slattach utility will abort if
             the unit number changes and ``-u unit-command'' was not speci-

     -z      Force redial redial-command upon startup irrespective of carrier.

     -L      Use uucp-style device locking.  You need it unless you start
             slattach from external program which already does uucp locking.
             Default case is no uucp locking to satisfy such programs.

     -K keepalive
             Set SLIP "keep alive" timeout in seconds.  If FRAME_END is not
             received in this amount of time, re-connect occurs.  The default
             value is no timeout.

     -O outfill
             Set SLIP "out fill" timeout in seconds.  It forces at least one
             FRAME_END to be sent during this time period, which is necessary
             for the "keep alive" timeout on the remote side.  The default
             value is no timeout.

     -S unit
             Set the SLIP unit number directly.  Use with caution, because no
             check is made for two interfaces with same number.  By default
             sliplogin dynamically assigns the unit number.

             Specify the name of the tty device.  Ttyname should be a string
             of the form 'ttyXX' or '/dev/ttyXX'.

     Only the super-user may attach a network interface.

     To detach the interface, use ``ifconfig interface-name down'' after
     killing off the slattach process using 'kill -INT'.  Interface-name is
     the name that is shown by netstat(1).

     To setup slattach to redial the phone when carrier is lost, use the -r
     redial-command option to specify a script or executable that will recon-
     nect the serial line to the slip server.  For example, the script could
     redial the server and log in, etc.

     To reconfigure the network interface in case the slip unit number
     changes, use the -u unit-command option to specify a script or executable
     that will be invoked as 'sh -c unit-command old new' where old and new
     are the slip unit numbers before and after reconnecting the line.  The
     unit number can change if you have more than one line disconnect at the
     same time.  The first to succeed in reconnecting will get the lowest unit

     To kill slattach use 'kill -INT' (SIGINT) which causes it to close the
     tty and exit.

     To force a redial, use 'kill -HUP' (SIGHUP) which causes slattach to
     think carrier was lost and thus invoke 'sh -c redial-command' to recon-
     nect to the server.

     If you use a hard-wired connection rather than a modem, invoke slattach
     with the -l option in order to ignore carrier on the slip line.

           slattach ttyd8
           slattach -s 4800 /dev/ttyd1
           slattach -c -s 38400 /dev/cuaa1
           slattach -r 'kermit -y dial.script >kermit.log 2>&1'

     Look for error messages in /var/log/messages (slattach is a daemon).
     Messages indicating the specified interface does not exit, the requested
     address is unknown, the user is not privileged and tried to alter an
     interface's configuration are logged there.  The slattach utility also
     logs failure to set the controlling terminal or failure to install signal
     handlers.  Upon connection and redial the ttyname and baud rate are
     logged and on shutdown the ttyname is logged.

     /var/run/slattach.<tty>.pid     with tty replaced by the terminal path
                                     name component of ttyname.  This file
                                     contains the numerical process ID of the
                                     slattach process and can be examined by
                                     scripts in order to send a signal to

     netstat(1), startslip(1), netintro(4), ifconfig(8), rc(8), sliplogin(8)

     The slattach utility appeared in 4.3BSD.

BSD                              April 4, 1993                             BSD