  PPP/SLIP/PLIP Configuration


  Some users may not have a network card in their computer.  In order
  for them to access the Internet or another machine, they need a proto-
  col that will work over a connection they have.  Linux is designed to
  use low-level PPP (Point to Point Protocol), and SLIP (Serial Line
  Internet Protocol) drivers over direct serial links or modem connec-
  tions, and PLIP (Parallel Line Internet Protocol) drivers over a par-
  allel (Laplink-style) cable.  Red Hat uses a different method of con-
  figuration from other Linux distributions.  Note that the Red Hat PPP
  module does not support the command line options of netconf.

  11..  NNeecceessssaarryy iinnffoorrmmaattiioonn ffoorr PPPPPP//SSLLIIPP ccoonnnneeccttiioonnss

  Before you start to setup up a PPP/SLIP connection, you need the
  following information:

  The phone number of the ISP (with area code if necessary) The type of
  server: PPP or SLIP A username for logging in to the PPP/SLIP server A
  password for logging in to the PPP/SLIP server Whether or not the PPP
  server uses PAP (Password Authentication Protocol)

  A modem is assumed to be connected to /dev/modem, which if properly
  setup, should be a link to /dev/ttyS0 or /dev/ttyS1 (COM1 and COM2,
  respectively, under DOS).


  22..  NNeecceessssaarryy iinnffoorrmmaattiioonn ffoorr PPLLIIPP ccoonnnneeccttiioonnss

  PLIP is not usually used in a dial-up environment, so configuring it
  is relatively simple.  You need to know the IP address of both the
  remote computer and the IP address of the computer you are planning to
  connect to the remote computer.


  33..  CCoonnffiigguurriinngg PPPPPP

  For most standard configurations, filling out the basic PPP dialog box
  should be enough to get up and running.

  Phone number: for your ISP's modem pool Modem port: where Linux will
  find your modem connected to your computer Use PAP authentication : If
  your ISP says you need it, set it Login name:  the login name provided
  by your ISP Password: the password provided by your ISP

  If everything goes well, you should be able to go into
  linuxconf|Control Panel|Control PPP/SLIP/PLIP links and select the
  configuration (usually ppp0).  Answer yes to the question 'Do you want
  to activate the network link?'  and you should soon be connected to
  the internet.  Disconnecting is done in the same manner.


  44..  CCoonnffiigguurriinngg SSLLIIPP

  Unfortunately, I do not have much experience here.  The major
  difference between PPP and SLIP is that your IP address, if not
  statically defined, is delivered outside of the protocol for SLIP and
  inside the protocol for PPP.  Therefore, one must have a shell script
  that can read an IP address from the console after you have logged on.


  55..  CCoonnffiigguurriinngg PPLLIIPP

  Assuming the wiring and IP addresses are correct, you should be able
  to plug the computers together, activate the link, and start working
  (telnet, ftp, www, etc.).


  66..  CCuussttoommiizziinngg tthhee PPPPPP CCoonnffiigguurraattiioonn

  Hardware:

  Use hardware flow control and modem lines -- the only reason you would
  want to turn this option off is if you had a direct cable connection
  between two computers.

  Escape control characters -- usually this option is negotiated
  automatically by the server, so it should be safe to leave it off.

  Abort connection on well-known errors -- self-explanatory.

  Allow any user to (de)activate the interface -- changes the file
  permissions on if-up and if-down so users do not have to be root to
  activate the link.

  Line speed -- assuming 16550, UARTS should be set to 57600 for
  14.4kbps modems and 115200 for 28.8kbps and up modems.

  Modem port -- usually /dev/modem, on older Linux distributions it may
  be set to /dev/cua1 or /dev/cua2; on newer distributions it may be set
  to /dev/ttyS0 or /dev/ttyS1.

  PPP options -- a place to put extra options for the pppd daemon that
  are not configured by Linuxconf.  See the pppd man page for details.

  Communication:

  Modem string -- consult your modem manual for the correct
  initialization string for your modem or leave it at the default ATZ.

  Modem dial command -- ATDT for a touch-tone line, or ATDP for a pulse
  line.

  Phone number -- the number for your ISP's modem pool.

  Debug Connection -- I believe this is to add debug options to pppd
  daemon at startup.

  Chat:

  These are the commands run by the chat script.  It waits for the
  server to send text prompts and then returns other text. It usually
  returns a name and password, but sometimes configuration information
  as well.

  Networking:

  Activate interface at boot time -- only useful if you have a leased-
  line or other permanent connection.

  Set default route -- useful when connecting to the Internet! It will
  send packets to an unknown host through the PPP interface.  It is
  important that you do not already have a default route set elsewhere,
  or this may not work.

  Restart link when connection fails -- will try to redial if the
  connection is lost.

  Time out value in seconds -- the interval of time after which PPP
  decides it will not connect and aborts.

  Maximum packet size -- the better the line conditions and the bigger
  the package size, the faster they transmit.  However, on noisy lines
  this will slow things down, because packets will occasionally have to
  be re-transmitted, and the bigger they are, the more has to be re-
  sent.

  Infrequently used options -- local and remote IP addresses are usually
  assigned automatically.  If you need to set them manually, your ISP
  will usually tell you.

  PAP -- enter your ISP provided username and password here, if your ISP
  uses PAP.


  77..  CCuussttoommiizziinngg SSLLIIPP CCoonnffiigguurraattiioonn

  SLIP configuration is similar to PPP configuration, except for the
  lack of PAP authentication options.


  88..  CCuussttoommiizziinngg PPLLIIPP CCoonnffiigguurraattiioonn

  There are no real options for PLIP configuration except weather or not
  to bring up the interface at boot time.  It either works or it
  doesn't.


  99..  TTrroouubblleesshhoooottiinngg PPPPPP ccoonnnneeccttiioonnss

  The most frequent problems related to PPP involve authentication.  You
  need to check that encryption settings and, of course, the username
  and password, match those that are required by your ISP.


  1100..  TTrroouubblleesshhoooottiinngg SSLLIIPP ccoonnnneeccttiioonnss

  Unfortunately, I do not have very much experience here.  Any
  suggestions?


  1111..  TTrroouubblleesshhoooottiinngg PPLLIIPP ccoonnnneeccttiioonnss

  Generally, you should not have any problems, provided that all of the
  hardware is functioning correctly.