Parts originally contributed by Gennady B. Sorokopud and Robert Huff.
27.3.1. Setting Up Kernel PPP
Before you start setting up PPP on your machine, make sure
that pppd is located in
/usr/sbin and the
directory /etc/ppp
exists.
pppd can work in two modes:
As a “client” — you want to connect
your machine to the outside world via a PPP serial
connection or modem line.
As a “server” — your machine is
located on the network, and is used to connect other
computers using PPP.
In both cases you will need to set up an options file
(/etc/ppp/options or
~/.ppprc if you have more than one user
on your machine that uses PPP).
You will also need some modem/serial software (preferably
comms/kermit), so you
can dial and establish a connection with the remote
host.
27.3.2. Using pppd as a Client
Based on information provided by Trev Roydhouse.
The following /etc/ppp/options might
be used to connect to a Cisco terminal server PPP line.
crtscts # enable hardware flow control
modem # modem control line
noipdefault # remote PPP server must supply your IP address
# if the remote host does not send your IP during IPCP
# negotiation, remove this option
passive # wait for LCP packets
domain ppp.foo.com # put your domain name here
:remote_ip # put the IP of remote PPP host here
# it will be used to route packets via PPP link
# if you didn't specified the noipdefault option
# change this line to local_ip:remote_ip
defaultroute # put this if you want that PPP server will be your
# default router
To connect:
Dial to the remote host using
Kermit (or some other modem
program), and enter your user name and password (or
whatever is needed to enable PPP on the remote
host).
Exit Kermit (without
hanging up the line).
Enter the following:
# /usr/sbin/pppd /dev/tty01 19200
Be sure to use the appropriate speed and device
name.
Now your computer is connected with PPP. If the
connection fails, you can add the debug
option to the /etc/ppp/options file,
and check console messages to track the problem.
Following /etc/ppp/pppup script will
make all 3 stages automatic:
#!/bin/sh
pgrep -l pppd
pid=`pgrep pppd`
if [ "X${pid}" != "X" ] ; then
echo 'killing pppd, PID=' ${pid}
kill ${pid}
fi
pgrep -l kermit
pid=`pgrep kermit`
if [ "X${pid}" != "X" ] ; then
echo 'killing kermit, PID=' ${pid}
kill -9 ${pid}
fi
ifconfig ppp0 down
ifconfig ppp0 delete
kermit -y /etc/ppp/kermit.dial
pppd /dev/tty01 19200
/etc/ppp/kermit.dial is a
Kermit script that dials and makes
all necessary authorization on the remote host (an example
of such a script is attached to the end of this
document).
Use the following /etc/ppp/pppdown
script to disconnect the PPP line:
#!/bin/sh
pid=`pgrep pppd`
if [ X${pid} != "X" ] ; then
echo 'killing pppd, PID=' ${pid}
kill -TERM ${pid}
fi
pgrep -l kermit
pid=`pgrep kermit`
if [ "X${pid}" != "X" ] ; then
echo 'killing kermit, PID=' ${pid}
kill -9 ${pid}
fi
/sbin/ifconfig ppp0 down
/sbin/ifconfig ppp0 delete
kermit -y /etc/ppp/kermit.hup
/etc/ppp/ppptest
Check to see if pppd is still running
by executing /usr/etc/ppp/ppptest, which
should look like this:
#!/bin/sh
pid=`pgrep pppd`
if [ X${pid} != "X" ] ; then
echo 'pppd running: PID=' ${pid-NONE}
else
echo 'No pppd running.'
fi
set -x
netstat -n -I ppp0
ifconfig ppp0
To hang up the modem, execute
/etc/ppp/kermit.hup, which should
contain:
set line /dev/tty01 ; put your modem device here
set speed 19200
set file type binary
set file names literal
set win 8
set rec pack 1024
set send pack 1024
set block 3
set term bytesize 8
set command bytesize 8
set flow none
pau 1
out +++
inp 5 OK
out ATH0\13
echo \13
exit
Here is an alternate method using chat
instead of kermit:
The following two files are sufficient to accomplish a
pppd connection.
/etc/ppp/options:
/dev/cuad1 115200
crtscts # enable hardware flow control
modem # modem control line
connect "/usr/bin/chat -f /etc/ppp/login.chat.script"
noipdefault # remote PPP serve must supply your IP address
# if the remote host doesn't send your IP during
# IPCP negotiation, remove this option
passive # wait for LCP packets
domain your.domain # put your domain name here
: # put the IP of remote PPP host here
# it will be used to route packets via PPP link
# if you didn't specified the noipdefault option
# change this line to local_ip:remote_ip
defaultroute # put this if you want that PPP server will be
# your default router
/etc/ppp/login.chat.script:
Note:
The following should go on a single line.
ABORT BUSY ABORT 'NO CARRIER' "" AT OK ATDTphone.number
CONNECT "" TIMEOUT 10 ogin:-\\r-ogin: login-id
TIMEOUT 5 sword: password
Once these are installed and modified correctly, all
you need to do is run pppd, like so:
# pppd
27.3.3. Using pppd as a Server
/etc/ppp/options should contain
something similar to the following:
crtscts # Hardware flow control
netmask 255.255.255.0 # netmask (not required)
192.114.208.20:192.114.208.165 # IP's of local and remote hosts
# local ip must be different from one
# you assigned to the Ethernet (or other)
# interface on your machine.
# remote IP is IP address that will be
# assigned to the remote machine
domain ppp.foo.com # your domain
passive # wait for LCP
modem # modem line
The following /etc/ppp/pppserv script
will tell pppd to behave as a
server:
#!/bin/sh
pgrep -l pppd
pid=`pgrep pppd`
if [ "X${pid}" != "X" ] ; then
echo 'killing pppd, PID=' ${pid}
kill ${pid}
fi
pgrep -l kermit
pid=`pgrep kermit`
if [ "X${pid}" != "X" ] ; then
echo 'killing kermit, PID=' ${pid}
kill -9 ${pid}
fi
# reset ppp interface
ifconfig ppp0 down
ifconfig ppp0 delete
# enable autoanswer mode
kermit -y /etc/ppp/kermit.ans
# run ppp
pppd /dev/tty01 19200
Use this /etc/ppp/pppservdown script
to stop the server:
#!/bin/sh
pgrep -l pppd
pid=`pgrep pppd`
if [ "X${pid}" != "X" ] ; then
echo 'killing pppd, PID=' ${pid}
kill ${pid}
fi
pgrep -l kermit
pid=`pgrep kermit`
if [ "X${pid}" != "X" ] ; then
echo 'killing kermit, PID=' ${pid}
kill -9 ${pid}
fi
ifconfig ppp0 down
ifconfig ppp0 delete
kermit -y /etc/ppp/kermit.noans
The following Kermit script
(/etc/ppp/kermit.ans) will enable/disable
autoanswer mode on your modem. It should look like
this:
set line /dev/tty01
set speed 19200
set file type binary
set file names literal
set win 8
set rec pack 1024
set send pack 1024
set block 3
set term bytesize 8
set command bytesize 8
set flow none
pau 1
out +++
inp 5 OK
out ATH0\13
inp 5 OK
echo \13
out ATS0=1\13 ; change this to out ATS0=0\13 if you want to disable
; autoanswer mode
inp 5 OK
echo \13
exit
A script named /etc/ppp/kermit.dial
is used for dialing and authenticating on the remote host.
You will need to customize it for your needs. Put your login
and password in this script; you will also need to change the
input statement depending on responses from your modem and
remote host.
;
; put the com line attached to the modem here:
;
set line /dev/tty01
;
; put the modem speed here:
;
set speed 19200
set file type binary ; full 8 bit file xfer
set file names literal
set win 8
set rec pack 1024
set send pack 1024
set block 3
set term bytesize 8
set command bytesize 8
set flow none
set modem hayes
set dial hangup off
set carrier auto ; Then SET CARRIER if necessary,
set dial display on ; Then SET DIAL if necessary,
set input echo on
set input timeout proceed
set input case ignore
def \%x 0 ; login prompt counter
goto slhup
:slcmd ; put the modem in command mode
echo Put the modem in command mode.
clear ; Clear unread characters from input buffer
pause 1
output +++ ; hayes escape sequence
input 1 OK\13\10 ; wait for OK
if success goto slhup
output \13
pause 1
output at\13
input 1 OK\13\10
if fail goto slcmd ; if modem doesn't answer OK, try again
:slhup ; hang up the phone
clear ; Clear unread characters from input buffer
pause 1
echo Hanging up the phone.
output ath0\13 ; hayes command for on hook
input 2 OK\13\10
if fail goto slcmd ; if no OK answer, put modem in command mode
:sldial ; dial the number
pause 1
echo Dialing.
output atdt9,550311\13\10 ; put phone number here
assign \%x 0 ; zero the time counter
:look
clear ; Clear unread characters from input buffer
increment \%x ; Count the seconds
input 1 {CONNECT }
if success goto sllogin
reinput 1 {NO CARRIER\13\10}
if success goto sldial
reinput 1 {NO DIALTONE\13\10}
if success goto slnodial
reinput 1 {\255}
if success goto slhup
reinput 1 {\127}
if success goto slhup
if < \%x 60 goto look
else goto slhup
:sllogin ; login
assign \%x 0 ; zero the time counter
pause 1
echo Looking for login prompt.
:slloop
increment \%x ; Count the seconds
clear ; Clear unread characters from input buffer
output \13
;
; put your expected login prompt here:
;
input 1 {Username: }
if success goto sluid
reinput 1 {\255}
if success goto slhup
reinput 1 {\127}
if success goto slhup
if < \%x 10 goto slloop ; try 10 times to get a login prompt
else goto slhup ; hang up and start again if 10 failures
:sluid
;
; put your userid here:
;
output ppp-login\13
input 1 {Password: }
;
; put your password here:
;
output ppp-password\13
input 1 {Entering SLIP mode.}
echo
quit
:slnodial
echo \7No dialtone. Check the telephone line!\7
exit 1
; local variables:
; mode: csh
; comment-start: "; "
; comment-start-skip: "; "
; end: