This document describes the configuration of the ppp-Dialer (point-to-point-protocoll) for an access to an Internet-Service-Provider (ISP) over a dial-in-phone-line.
This
configuration comprises the storage of the user-id and -password for
the access to the ISPs-system in a separate, highly protected
file.
Further it parameterizes the ppp-daemon so, that the
connection is established automatically when a request to
world-wide-Internet is made and terminated after a defined idle-time.
Credits:For
a newbie like me it was pretty hard to seperate all the term
associated with setting up a (secure and reliable) connection to an
ISP.
A big help was Heimo Schöns HOWTO
(http://howto.htlw16.ac.at/at-highspeed-howto.html
- in german) which allowed me to seperate the tasks and do them step
by step.
Operating-system installed ;-).
Logged on as user root.
Installation-instruction:The
following files can be copied and directly transferred to the target;
to do so follow
this link for an explanation how to copy text from a web-browser to a
file .
Store the
user-id and password for the connection to the ISP:The
Internet-Service-Provider usually provides an user-id and a password
to identify individual clients.
During the dial-in-procedure the
ISP performs an identification and requests user-id and password.
There
are 2 different authentification-protocols (PAP and CHAP); if you are
not sure what protocol the ISP uses it is recommended to store
user-id and password for both protocols.
For
the PAP-authentification edit the file
/etc/ppp/pap-secrets and add the bold printed line.
Instead of the italics printed values in the examples, enter
user-id and password provided by the ISP:
# Secrets for
authentication using PAP
# client server secret IP
adresses
user-id * password
For
the CHAP-authentification edit the file
/etc/ppp/chap-secrets and add the bold printed line.
Instead of the italics printed values in the examples, enter
user-id and password provided by the ISP:
# Secrets for
authentication using PAP
# client server secret IP
adresses
user-id * password
Store the
modem-commands for dialing and the phone-number to dial for the
connection to the ISP:The
following example is specific for dial-in to the ISP-Provider UTA in
Austria. It works with standard-modems supporting the
Hayes-command-set.
N.B.:
I tried to make an internal DSP (Digital-Signal-Processor) modem to
work - but failed after hours of frustrating trials.
My strong
recommandation is: if you do not have a modem with Hayes-command-set
by now, buy a second hand external modem (they all support the
Hayes-command-set). They are cheap to get - particularly on
auction-platforms.
To
define the modem-commands and the phone-number of the ISP, create the
file
/etc/sysconfig/network-scripts/utanet-ppp0 and add
enter the following string.
Instead of the italics printed values
in the example, enter the phone-number for dial-in to your ISP:
ABORT BUSY ABORT “NO
CARRIER” “” atz OK atx3dt1002019088333
CONNECT
Please
notify that the filename (utanet-ppp0)
can be chosen freely - to be consistent, the above one will be
referred in the next step.
Edit the
configuration file for the dialer-program (pppd):The
dialer-program is controlled by the parameters in the file
/etc/ppp/options ;
the bold printed values can be modified according to your needs:
#
# Dial only if
connection to an address outside the internal network is
requested
demand
#
# Disconnect the phone-line if there is
no traffic for x seconds
idle 180
#
# Unknown meaning
of the following 2 parameters; it just does not work without
them
ipcp-accept-remote
ipcp-accept-local
#
# Lock the
modem against demands from other processes;
# this prevents e.g.
the fax-program from claiming access to the modem
lock
#
#
The computer on Internet-Service-Provider (ISP) does not have to
identify itself
# against the computer dialing-in
noauth
#
#
This connection is the default-router from the internal network to
the ISP.
defaultroute
#
# User, for whom the password is
read out of the file 'pap-secrets' or 'chap-secrets'
user
user-id
#
# Name of the connection for
identification in ifconfig
remotename ppp0
#
#
COM-interface and maximum speed of the modem
/dev/ttyS1
115200
#
# Characterset with 8 Bits can be processed on
this machine
asyncmap 0
#
# Hardware-Flow-Control with the
modem
crtscts
#
# Control file with commands for the modem
and dial-in phone-number
connect '/usr/sbin/chat -f
/etc/sysconfig/network-scripts/utanet-ppp0'
#
# End of
file
Setting the
access-rights for an automated startupAs
a prerequisite for automated startup the access-rights of the
dialer-program pppd must be set as follows:
chmod
4711 /usr/sbin/pppd
Automatic start of
the dialer-program when Linux is startedTo
start the dialer, the file
/etc/rc.d/rc.local is appended with the following
command-lines:
# Start the dialer for
connecting to an Internet-Service-Provider by dial-in
# Do this
always after starting the firewall to avoid security holes
# N.B.:
I do not know why, but it does not work without the
TCP/IP-address
/usr/sbin/pppd
:195.70.224.61
The
files can only be edited with access-rights as 'root'.That
the change takes effect it is requiered to execute
the file
or
to restart Linux**/etc/rc.d/rc.local
After
a new startup of Linux** it can be verified if the dialer-program is
running by issuing the command ifconfig
The
output should show a record with the remotename
ppp0 in the left column and statistics in the right column.
If there is no record for
ppp0, start the dialer program manually by
issuing the commandpppd
:195.70.224.61
and
thereafterifconfig
If
there is still no record for
ppp0, inspect the file
/etc/ppp/options for
typing errors.
After
ppp0 leaves a record in ifconfig, try to establish a
connection to the Internet-Service-Provider by issuing the
commandping
195.3.96.67
The
modem should start dialing (watch the lights if it is an external
modem or listen to the sound) and establish a connection to the ISP.
If
there is no dialing activity on the modem, inspect the file
/etc/sysconfig/network-scripts/utanet-ppp0
,
or however you named it, for typing errors.
If
there is dialing activity on the modem - but it hangs up shortly
after establishing connection to the ISP, inspect the file
/etc/ppp/pap-secrets
or
/etc/ppp/chap-secrets
respectively for a correct spelling of user-id
and password.
N.B.:
As this Computer is the router (TCP/IP-address 192.168.0.254) and has
itself defined as Gateway (TCP/IP-address 192.168.0.254), it tries to
establish the connection over address 192.168.0.254 and not over the
modem.
Therefore the result of the ping is not as expected but
ping
195.3.96.67
The
expected results of a
ping will be shown after Setting
up firewall and masquerading .