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NAME    [Toc]    [Back]

     slattach -- attach serial lines as network interfaces

SYNOPSIS    [Toc]    [Back]

     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

DESCRIPTION    [Toc]    [Back]

     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 background.

     -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 numbers
 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 specified.

     -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 reconnect
 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 reconnect
 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.

EXAMPLES    [Toc]    [Back]

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

DIAGNOSTICS    [Toc]    [Back]

     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.

FILES    [Toc]    [Back]

     /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

SEE ALSO    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

     The slattach utility appeared in 4.3BSD.

FreeBSD 5.2.1			 April 4, 1993			 FreeBSD 5.2.1
[ Back ]
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