startslip - Configures SLIP connections
/usr/sbin/startslip [-i filename]
Specifies the file containing the startslip subcommands for dial-out
The startslip program configures two types of SLIP connections:
+ Dial-in connections -- The system is to answer calls from remote sys-
+ Dial-out connections -- The system is to place calls to a remote sys-
If your system is configured as a dial-in system, a getty process is con-
tinuously run on the serial line that is connected to a modem. When a call
comes in, getty prompts for a login name. If the login name matches a SLIP
user name entry in the /etc/passwd file, getty starts startslip as a login
shell. The startslip program then reads the /etc/slhosts files until it
finds an entry matching the current login name. If an entry is found,
startslip configures the tty line as a SLIP link using information in the
slhosts file entry.
See Network Administration: Connections for information on setting up your
system as a SLIP dial-in system.
If your system is configured as a dial-out system and you want to create a
SLIP connection to a remote system, you invoke the startslip program from
the command line and specify -i filename. The filename file contains the
startslip subcommands to set up the dial-out connection (see the Subcom-
mands section). After making the connection, startslip runs in the back-
When you are finished with the SLIP connection, you can either turn off
your modem or kill the tty process. The tty process ID is stored in the
/var/run/ttyxx.tel-pid file, where ttyxx specifies the terminal line.
The following startslip subcommands can be used to set up SLIP dial-out
connections. The subcommands are specified in a SLIP setup script file
that is passed to startslip with the -i filename option. In the setup
script file, any text following the comment character (#) is ignored. In
addition, each line can contain up to 256 characters.
Specifies the callback option. If this subcommand is specified,
startslip raises Data Terminal Ready (DTR) if carrier is lost during a
read from the serial line.
Causes startslip to configure the network interface with the values
specified with the myip, dstip, and netmask subcommands, and to attach
the serial line to the network interface. If the gateway is specified,
it also adds the destination IP address as the default gateway.
Specify this subcommand at the end of the script file. Specify the
myip, dstip, netmask, and, optionally, gateway subcommands prior to
Enables debugging and prints debug messages to the logfile file.
Specify this subcommand at the beginning of the script file.
Dials the telephone_number. The format of telephone_number is a string
of numbers with no separators. Specify this subcommand after opentty
dstip hostname | IP address
Sets destination IP address. You can specify either a host name or IP
Terminates startslip and exits.
expect string timeout seconds errmsg message
Causes startslip to wait to receive string from the remote host. If a
match occurs, startslip continues reading this file. If a match does
not occur after the specified seconds, startslip prints message and
Specify this subcommand after opentty.
Flushes the read and write queues.
Sets the destination IP address as the default gateway.
Specifies a hard-wired link. Ignore modem control signals (CLOCAL flag
set in termios structure) when switching to a SLIP connection.
Enables ICMP traffic suppression.
Sets the modem type. The modem_name specified must be defined in the
myip hostname | IP address
Sets my local IP address. You can specify either a host name or IP
Sets the network mask.
opentty ttyxx speed baud_rate
Opens the ttyxx serial line and sets line speed to baud_rate. The
value for baud_rate must be one of the standard speeds listed in
Prints string to the standard output; everything to the end of the
line, including punctuation, is printed. Use this subcommand to cue
the user as to which subcommand is executing.
raddr myip | dstip | netmask
Causes startslip to read either the local IP address, destination IP
address, or network mask from the remote system in dotted decimal nota-
tion. Use this subcommand after opentty. An expect subcommand should
be used prior to raddr ensure that the desired information is read.
Sends the string to the serial line. Use this subcommand after
If string is set to the keyword ASKPASSWD, startslip prompts for a
password, reads it from standard input, and sends it to the serial
Causes startslip to sleep number_of_seconds before continuing to read
Displays current status of startslip.
Enables TCP header compression.
Enables automatic TCP header compression.
Only a person with superuser authority can run the startslip program.
The following sample setup script file shows how to use various startslip
# set modemtype before dialing
# microcom modem attributes defined in /etc/acucap
printmsg open /dev/tty00 at speed 38400
opentty tty00 speed 38400
printmsg dial 18154231234
# expect login prompt. timeout and exit after 5 seconds.
expect ogin: timeout 5 errmsg "not getting login: prompt"
printmsg send login
# expect password prompt. timeout and exit after 5 seconds.
expect assword: timeout 5 errmsg "not getting Password: prompt"
printmsg Prompt and send password
# expect Starting SLIP after login
expect SLIP timeout 10 errmsg "not getting startup message"
# connect slip - ifconfig, slattach
printmsg connect slip
Specifies the command path
Contains the startslip process ID
Specifies the termios header file
Files: acucap(4), slhosts(4)
Network Administration: Connections
Specifications: A Nonstandard for Transmission of IP Datagrams Over Serial
Lines: SLIP (RFC1055)
Compressing TCP/IP Headers for Low-speed Serial Links (RFC1144)