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The options may be given on one line or each on a separate line.
Many options files are much longer, and come with a description of
each option. Here, the options mean, in order, don't remap any
characters between the PPP client and server; always use password,
PAP, or CHAP authentication when making a connection; use the
modem's hardware handshake lines for flow control; lock the serial
port when in use so no other programs can access it; and do not
use the IPX network protocol.
* For connection set-up on each individual serial port or PPP host,
there will either be an /etc/ppp/options.ttyS1, for example,
options file for /etc/ttyS1, or a file for your ISP in the
/etc/ppp/peers directory. The default is often called
/etc/ppp/peers/provider. Here is a sample of the default provider
file:
noauth
connect "/usr/sbin/chat -v -f /etc/chatscripts/provider"
defaultroute
/dev/ttyS1
38400
persist
There might be an explanation of these and other options in the
/etc/ppp/peers/provider file itself. You can also refer to the
pppd manual page for details. Briefly, they mean: do not use PAP
authentication for this connection; use the chat program and the
/etc/chatscripts/provider script, which is described above, to
dial the phone and log in; set the network default route to the
PPP connection (so when your network software needs to resolve an
network address that is not on your local machine(s), it will use
the PPP connection to the Internet); use /dev/ttyS1 as the serial
port for the connection; set the modem speed to 38400; and keep
the pppd daemon running even if the connection fails.
* That is all of the configuration you need. To actually start and
stop PPP, there are often /usr/bin/pon and /usr/bin/poff scripts
(in Debian), or something similar, and they are usually very
simple, and only contain the command:
$ /usr/sbin/pppd call ${1:-provider}
This will start pppd and use the call option to call the server
that you type on the command line, or the provider given in the
/etc/ppp/peers/provider file if you do not specify a remote
server. After making the call and logging in (about 30 seconds),
you should be able to use the /sbin/ifconfig program to determine
that the connection really did establish a PPP interface (the
first will be ppp0, the second will be ppp1, etc., depending on
how many simultaneous PPP connections you have. If something goes
wrong, you can look at the /var/log/ppp.log file to determine what
happened. You can also view the log as the connection is being
made, by "tailing" it in another window; that is, viewing it as
pppd logs the connection's status information. To do this, use the
command (again, as root):
$ tail -f /var/log/ppp.log
On some systems the PPP output is directed to /var/log/messages,
in which case your system may not have a dedicated PPP log file.
You should be also able to ping one of your ISP's domain names (e.g.,
mail.isp.com) and receive a response.
These are the most basic steps for configuring a PPP connection. You
will also need to take into account what other network connections may
be present (for example, if there's an Ethernet connection that has
already been assigned the default route), as well as various security
measures at your ISP's end. If you're having trouble making the
dial-up connection, usually the best way to determine what may be
going wrong is to use Seyon, minicomm, kermit, or some other program
to dial and log in manually to the ISP, and determine just exactly
what you have to do to log in, then duplicate that in the PPP scripts.
Most Linux documentation also has additional instructions for
configuring PPP connections. Refer to ("Where Are the Linux FTP
Archives?") ("Where Is the Documentation?")