  Linux PPP HOWTO
  Al Longyear, longyear@netcom.com
  v1.9, 1 May 1995.

  This document contains a list the most Frequently Asked Questions
  (FAQ) about PPP for Linux (and their answers). It is really not a
  HOWTO, but is in `classical' Question / Answer form.

  1.  Preface

  Please send any corrections to longyear@netcom.com.

  This is but one of the Linux HOWTO/FAQ documents. You can get the
  HOWTO's from sunsite.unc.edu:/pub/Linux/docs/HOWTO (this is the
  `official' place) or via WWW from the Linux Documentation home page
  (http://sunsite.unc.edu/mdw/linux.hmtl). You cannot rely on the
  HOWTO's being posted to comp.os.linux.answers, as some news feeds have
  complained about their size.

  Throughout this document, I have used the word `remote' to mean `the
  system at the other end of the modem link'. It is also called `peer'
  in the PPP documentation. Another name for this is called the
  `gateway' when the term is use for routing. Its IP address will show
  as the `P-t-P' address if you use ifconfig.

  Microsoft is a registered trademark of Microsoft Corporation. Morning
  Star is a registered trademark of Morning Star Technologies
  Incorporated. All other products mentioned are trademarks of their
  respective companies.



  2.  General information


  2.1.	What is PPP?

  PPP, or Point-to-Point Protocol, is a recognized `official' internet
  protocol. It is a protocol used to exchange IP frames (and others)
  over a serial link. The current RFC for PPP is 1661. There are many
  related ones.

  Contrary to what some people think, it does not mean "Peer to Peer
  Processing"; although you may do peer-peer communications using TCP/IP
  over a PPP link.



  2.2.	My university (company) does not support PPP. Can I use PPP?

  In general, no. A `classical' PPP implementation requires that you
  make changes to the routes and network devices supported by the
  operating system. This may mean that you will have to rebuild the
  kernel for the remote computer.

  This is not a job for a general user. If you can convince your
  administration people that PPP is a `good thing' then you stand a
  chance of getting it implemented. If you can't, then you probably
  can't use PPP.

  However, if you are using a system which is supported by the people
  who are marketing the "TIA" (The Internet Adapter) package, then there
  is hope. I do not have much information on this package, however, from
  what I have found, they plan to support PPP in "the next version". (My
  information may be old. Contact them directly.  Information on TIA is
  available at ftp.marketplace.com in the /pub/tia directory.)
  If your system is not supported by TIA and you can't convince the
  admin group to support PPP then you should use the `term' package.
  Some service providers will object to you running `term'. They have
  many different reasons, however the most common is `security
  concerns'.

  There is a version of TIA for Linux.


  2.3.	Where is PPP?

  It is in two parts. The first part is in the kernel. In the kernels
  from 1.1.13, the driver is part of the network system drivers.

  Do not replace the driver in the kernel with a version from the pppd
  package!!!

  The second part is the `daemon' process, pppd. This is a required
  process. The source to it is in the file ppp-2.1.2b.tar.gz located on
  sunsite.unc.edu in the /pub/Linux/system/Network/serial directory.

  For kernels before 1.1.13, the necessary driver is included in the
  daemon code.



  2.4.	I just obtained PPP. What do I do with it?

  Read The Fine Material available.

  Start by reading the README file and then the README.linux file. The
  documentation sources are listed below.



  2.5.	(Where's the documentation? Is there a HOWTO?, etc.)  Where are
  additional sources of information for PPP?

  There are several sources of information for the PPP protocol as
  implemented under Linux.


  o  The README file in the source package.

  o  The README.linux file in the source package.

  o  The Net-2-HOWTO document.

  o  The Network Administration Guide.

  o  The pppd man page.

  o  The ppp FAQ document. (This is not it, by the way.)

  The HOWTO file is stored in the usual place for the Linux HOWTOs.
  That is currently on sunsite.unc.edu in the directory
  /pub/Linux/docs/HOWTO.

  The Network Administration Guide is available in the docs/linux-doc-
  project/nag directory on sunsite. It is published by O'Riellly and
  Associates. So, if you want a really professional document, then buy a
  copy from your local bookstore.

  The `man' pages are included in the source package. You will probably
  have to move them to the normal man directory, /usr/man/man8 before
  the man command may find them.  Alternately, you may use nroff and
  more to view them directly.

  The PPP faq document describes the PPP protocol itself and the various
  implementations. You will find the FAQ for the usenet news group,
  comp.protocols.ppp, archived on rtfm.mit.edu in the /usenet directory.
  It is in eight parts at the present time.



  2.6.	Where should I post questions about PPP?

  The primary usenet group for the PPP implementations is
  comp.protocols.ppp. Use this group for general questions such as "How
  do I use pppd?" or "Why doesn't this work?".

  Questions such as "Why won't pppd compile?" are generally linux
  related and belong on the comp.os.linux.networking group.

  Please don't use comp.os.linux.help.



  2.7.	The PPP software doesn't work. HELP!!!

  This is one of the most sickening questions. I realize that this is a
  plea for help. However, it is practically useless to post this message
  with no other information. I, and most others, will only ignore it.

  Please see the question regarding errors which normally occur at the
  modem's disconnection. They are not the cause of a problem, only a
  symptom. Posting a message with only those errors is also meaningless.

  What is needed is the output of the system log (syslog) when you run
  the pppd program with the option `debug'. In addition, if you are
  using chat then please use the `-v' option to run the sequence with
  verbose output.

  Please include the output from the kernel's startup. This shows the
  various kernel hardware information such as your UART type, PPP
  version, etc.

  Please include all information that you can relating to the problem.
  However your system configuration, disk drive configuration, terminal
  type, mouse location and button status, etc. are irrelevant. What is
  important is the system to which your are trying to contact, the ppp
  (or terminal server) that they are using, the modem types and speed
  that you are using, etc.

  Take care and go through the output. Remove the references to the
  telephone number, your account name, and the password. They are not
  important to analyzing the problem and would pose a security risk to
  you if you published them to usenet. Also discard the lines which
  neither come from the kernel nor pppd.

  Do NOT run the pppd program with the option `kdebug 7' and post that!

  If the problem warrants examining the data stream, then you will be
  contacted by email and asked to mail the trace. Usenet already costs
  too much for too many people.

  Information is written to various levels. The debug information is
  written to the debug level. The informational messages are written to
  the info level. The errors are written to the error level. Please
  include all levels the the `local2' group which come from the pppd
  process.

  In addition, please do not delete the time stamp information. It is
  important.



  2.8.	Can I use the same local IP address for each line of a PPP
  server?

  Yes. The local address is not significant to the local system. You
  must have a unique remote IP address. The routing is performed based
  upon the remote IP address and not the local IP address.



  3.  Other implementations


  3.1.	Do you know of a implementation for PPP other than Linux? I
  would like one for HP-UX, or AIX, or ... (you fill in the blank) ?

  Check the PPP FAQ document mentioned above.

  AIX is due to be supported in the 2.2 version of the pppd process.
  HP-UX is, to my knowledge, only supported by the Morning Star
  commercial package.

  If you don't find one listed then post to the comp.protocols.ppp group
  and not the Linux group.

  (Please don't mail me asking for "Do you know of a PPP package for
  ..."?	These requests will now be `appropriately' filed. ;-))



  3.2.	Did you know that there is a program called `dp'?

  Yes, we know. The dp package was considered very early in the
  development stage quite a few months back. It is nice.  It supports
  'demand dial'. It also only works with systems which support streams.
  This is primarily the SunOS (Solaris) operating systems.

  Linux, at the present time, does not supports streams.

  There are several other packages for PPP available on the `net'. The
  `portable ppp' package is very much like the TIA code. There is
  another package called simply `ppp'. There is code for PPP in the KA9Q
  package.

  Of all of the packages available, the pppd package was the closest to
  the requirements and functions of Linux to warrant the port.

  (If you want more information about these other packages, ask in the
  comp.protocols.ppp group!)



  3.3.	What RFCs describe the PPP protocol?

  The current implementation of PPP is a mixture of several.  The major
  portion of the PPP code is written against the RFCs 1331 and 1332.
  These RFCs were later obsoleted. 1331 was replaced by 1548 and that,
  in turn, was obsoleted by 1661 six months later.

  Most implementations of PPP will be happy to talk to the Linux PPP
  code.

  A complete list is in the PPP faq.

  [to quote the FAQ document]:


       All of 1134, 1171, and 1172 (and 1055, for that matter :-)
       have been obsoleted. They're interesting only if you want to
       debug a connection with an ancient PPP implementation, and
       you're wondering why (e.g.)  it asked you for IPCP option 2
       with a length of only 4, and Compression-Type 0x0037.

       (There's a lot of that still running around - be careful out
       there.)


  Linux PPP will not support this.



  4.  Compatibility


  4.1.	Can PPP talk to a SLIP interface?

  No. SLIP works with SLIP. PPP works with PPP.

  Some vendors may offer products which work both as SLIP and PPP.
  However, they must be configured to run in one mode or the other.
  There is no present method to determine, based upon the protocol
  passed at the time of a connection, which combination of SLIP
  protocols or PPP is being requested.



  4.2.	Which is better? PPP or SLIP?

  IT DEPENDS UPON MANY FACTORS. The people who post this type of
  question have usually not read the Net-2-HOWTO document.

  A good technical discussion is available at Morning Star's www server,
  www.morningstar.com.



  4.3.	Is CHAP or PAP better for authentication?

  If you have the choice, use CHAP. Failing that, PAP is better than
  nothing.



  5.  Authentication files


  5.1.	What goes into the /etc/ppp/pap-secrets file? Do you have a sam-
  ple?

  The PAP protocol is most often implemented as your user name and
  password. You need to include the name of the remote system, your
  account name, and the password. If the user on abbot wishes to call
  costello, the entry would be similar to the following.

     #remote	account	password	IP address list
     *		abbot	firstbase


  5.2.	What goes into the /etc/ppp/chap-secrets file? Do you have a
  sample?

  The most common problem is that people don't recognize that CHAP deals
  with a pair of secrets. Both computers involved in the link must have
  both secrets to work.

  For example, if abbot wants to talk to costello, then abbot's file
  would have:


	  #local	remote		secret		IP address list
	  abbot		costello	firstbase
	  costello	abbot		who


  And costello's file would have:


	  #local	remote		secret		IP address list
	  abbot		costello	firstbase
	  costello	abbot		who



  6.  Construction problems


  6.1.	I get compile errors when I try to compile the kernel

  With the release of the 1.2 kernel for Linux, the ppp driver is a
  standard part of the network devices. Each kernel should include the
  software necessary to make the PPP support within the kernel. Please
  do not edit the ppp driver. It has been pre-configured for the kernel.

  If you are attempting to run ppp on kernels prior to the 1.2, then
  please consider upgrading the kernel. The 1.0 kernels require patching
  to support the ppp driver. The 1.2 kernels supported ppp to some
  degree, but also required changes depending upon the specific patch
  level.


  7.  Problems running pppd


  7.1.	PPPD won't run unless you are root

  The pppd process needs to make changes to the networking system and
  this can only be done if you are the root user. If you wish to run
  pppd from other than the root user then the pppd program needs to be
  secured 'suid to root'.

	  chown root pppd
	  chmod 4755 pppd


  If you wish to control the pppd access to a select group of people,
  then make the pppd process owned by the group and do not permit all
  others to run the program.


  7.2.	The ppp-2.1.2b package says it needs the 4.6 libraries

  Sorry, I goofed. You will have to forego the binaries and re-compile
  the code yourself. It is easy. Go to the pppd directory, delete the
  bad binary, and issue the command `make'. Go to the chat directory and
  do the same if you want a corrected chat program.

  You must have the C language compiler and GNU make installed to
  rebuild the PPP software.

  It turns out that when I compiled the ppp-2.1.2b package, while I used
  the proper definitions, I used the 4.6 libraries. One of these days,
  Al may finally get his act together . . . .

  Or, you can get binaries from the Slackware 2.0.2 (or later) package.
  They are in the ppp.tgz file in the `n' series of disks.

  Please use the source in the ppp-2.1.2b to compile the code.	The
  source has been corrected over the `a' package.



  7.3.	unable to create pid file: no such file or directory

  You need to create the directory /var/run. On earlier Slackware
  distributions, this was a symbolic link to the /etc directory.

  This is a warning. The ppp software will work normally in spite of
  this message. However, the ppp-off script depends upon this file. It
  is a good idea to create the directory or make the link to the
  appropriate location.

  The posix header, paths.h, defines the location for the pid file under
  the name "_VAR_RUN". If you wish to use a different directory for PPP
  and others, change the value for this define and rebuild the software.



  7.4.	/etc/ppp/options: no such file or directory

  You need to create the directory /etc/ppp and have a file called
  'options' in that directory. It needs to be readable by the pppd
  process (root).

  The file may be empty. To make an empty file use the `touch' command.

  See the pppd man page, pppd.8, for a description of this file.



  7.5.	Could not determine local IP address

  This happens with many configurations of the Telebit Netblazer. The
  problem is not the terminal server, but the site which has not
  configured the terminal server with a set of IP addresses.
  The Netblazer does not have your IP address. You do not have your IP
  address. The link will not work unless both IP addresses are known.

  You must have been given a piece of paper with both IP addresses
  written upon it. You must tell the Netblazer the IP addresses to be
  used. Use the local IP address and the remote IP address as a
  parameter to the pppd process.

  Use the pppd option format of:

  local_ip:remote_ip

  (That is the local IP address, a colon, and the remote IP address.)



  7.6.	Could not determine remote IP address

  See the previous question.



  7.7.	I keep getting the message to the effect that the magic number
  is always NAKed. The system will not connect.

  There is a one in over four billion chance that the two systems have
  chosen the same magic number. If you get a continual failure about the
  magic number, the chances that this is a fluke will geometrically
  reduce.

  The two most common reasons for this failure are:


  o  The remote ppp software is not running when you think it is.  Is
     the remote system configured to run PPP? Is the ppp process in the
     expected location?	Is the privileges suitable so that you may run
     it?

     This would indicate that the shell is doing the local echo of the
     data. This is the more common reason.


  o  The modem has disconnected immediately upon making the connection
     and logging you on to the remote. Most modems are configured to
     echo the data sent to them and you are seeing the local echo from
     the modem.


  In either case, the Linux system is sending data to the remote which
  is being fed immediately back into the serial receiver. This is not an
  acceptable condition. You have what is called a "loop".



  7.8.	protocol reject for protocol fffb

  This usually occurs when you are trying to connect to a Xyplex
  terminal server. Version 5.1 of the Xyplex terminal server software,
  according to Xyplex, has numerous problems with PPP. It is strongly
  recommended that you update the Xyplex software to at least version
  5.3.

  If you must use version 5.1, then use the pppd option "vj-max-slots 3"
  to limit the number of slots to three. The problem on the Xyplex
  server is that it will accept the request for the default 16 slots,
  but fail to operate beyond the third slot. It should have return a NAK
  frame with the limit, but it does not.

  Alternately, you can disable the Van Jacobson header compression with
  the option "-vj".



  7.9.	The PPP software connects, sends quite a few frames, but still
  does not seem to connect. Why is that?

  Examine the system log when you use the "debug" option. (You will need
  the system log data anyway if you are going to ask for help.)	If the
  trace shows that it is sending the LCP-request frame over and over
  again and the id number is not incrementing then you are not
  exchanging frames with the remote PPP software.

  Three common reasons for this are:

  o  You don't have the ppp software running on the other end. You are
     sending the PPP frames to some other program which is probably
     saying "What is this #$%^ ?"

     Please make sure that you have the ppp software started on the
     other end before you enter the ppp protocol sequence. Try to use a
     normal modem program and go through the logon sequence that you
     would normally do. Do you see the ppp frames being sent to you?

     The ppp frames are fairly distinctive. They will be about 16
     characters in length and contain several { characters. They should
     not have a carriage return character after them and are sent out in
     a burst with a pause between the bursts.

  o  The line is not "eight bit clean". This means that you need to have
     eight data bits, no parity, and one stop bit. The PPP link
     absolutely requires eight data bits.

     The pppd software will automatically put the line into eight data
     bits, no parity, and one stop bit. The remote must match this
     configuration or framing and parity errors may occur.

     PPP will escape characters. It is not possible for it to escape
     bits as kermit does. PPP will not work with a seven bit
     communications link.

     There is a compile option in the ppp.c driver (part of the kernel)
     called CHECK_CHARACTERS which will include additional code in the
     driver to provide additional checking on the input characters. It
     will be able to tell you if the parity was enabled or if the remote
     system always sent the characters as seven bits.

  o  The remote is configured to require authentication such as PAP or
     CHAP. You have not configured the local system to use this feature.
     Therefore, the remote is discarding all of your frames until it
     sees a valid authentication frame from you.  Since you are not
     configured to generate the frames, the IPCP frames which you send
     are being ignored.

     In this case, either configure the remote to not expect
     authentication or configure the local system to do authentication
     and supply the proper secrets.

     Examine the receipt of the LCP configure frame. If it shows an
     'auth' type, then the remote is configured for authentication.


  7.10.	I can't connect to the merit network.

  Some users of the merit network have indicated that it needs PAP. Did
  you try PAP authentication?



  8.  DIP


  8.1.	DIP does not have support for PPP's mode

  The current version of dip-uri supports PPP in that it will execute
  the pppd process when you execute `mode ppp'. However, there are many
  options which are needed for the proper operation of pppd. Since dip
  does not pass these to the program, they must be stored in the
  /etc/ppp/options file.

  The dip program controls the establishment of the SLIP link. It
  controls the SLIP link with the aid of slattach, ifconfig, and route.
  These programs may be used to establish a SLIP link. They are not
  useful for the establishment of a PPP link.

  The dip program may be used to dial the telephone and start the ppp
  software on the remote system. It is best used in this mode as the
  parameter to the `connect' option. However, you have the option to use
  dip to control the link. It is not important how pppd be executed to
  run the ppp link. It is only important that it be executed as it is a
  mandatory program for the PPP protocol.



  9.  Process termination


  9.1.	Is there a `dip -k' for PPP?

  No. There is no `dip -k'.

  In the chat directory, there is a `ppp-off' script. This will stop the
  ppp link in the same manner as the 'dip -k'.

  I have included it below. (Cut it out. Store it in its own file.  Make
  the file executable with chmod.)

  ______________________________________________________________________
  #!/bin/sh
  DEVICE=ppp0
  #
  # If the ppp0 pid file is present then the program is running. Stop it.
  if [ -r /var/run/$DEVICE.pid ]; then
	  kill -INT `cat /var/run/$DEVICE.pid`
  #
  # If the kill did not work then there is no process running for this
  # pid. It may also mean that the lock file will be left. You may wish
  # to delete the lock file at the same time.
	  if [ ! "$?" = "0" ]; then
		  rm -f /var/run/$DEVICE.pid
		  echo "ERROR: Removed stale pid file"
		  exit 1
	  fi
  #
  # Success. Let pppd clean up its own junk.
	  echo "PPP link to $DEVICE terminated."
	  exit 0
  fi
  #
  # The ppp process is not running for ppp0
  echo "ERROR: PPP link is not active on $DEVICE"
  exit 1
  ______________________________________________________________________




  9.2.	PPP does not hangup the modem when it terminates

  There are several reasons for this.

  o  Did you use the pppd `modem' parameter?  This parameter controls
     whether or not the pppd process is to control and honor the signals
     reflecting the modem status. This parameter is explained in the man
     page for pppd.

  o  Do you have the modem presenting the DCD signal and honoring DTR?
     The Hayes sequence for this is usually "&C1". If you reset the
     modem during the connection sequence with "ATZ" then ensure that
     your modem is configured correctly.

     The DTR signal is generated by the computer and instructs the modem
     to disconnect. Hayes sequence for this is usually "&D1" or "&D2"
     with "&D2" being the preferred setting for PPP. Many manufacturers
     will ignore the DTR condition in their `factory defaults' setting.

  o  Did you use a cheap cable which does not pass the DCD signal?
     Macintosh `classic' cables are notorious for this problem. That
     Macintosh does not use this signal.

  o  For dial-in connections, did you exec the pppd process properly?

     The pppd process should be `exec'ed from the script rather than
     simply executed. If you attempt to simply run the pppd process then
     it will be the shell which will receive the SIGHUP hangup signal
     and not the pppd process.

     The `shell' script should have a format similar to the following:

     ___________________________________________________________________
     #!/bin/sh
     exec pppd -detach modem ...
     ___________________________________________________________________



  10.  Data Transfer related issues


  10.1.	The ftp transfers seems to die when I do a `put' operation.
  They will work correctly if I `get' a file. Why?

  Do you have the flow control enabled? Flow control is set by the pppd
  option crtscts for RTS/CTS and xonxoff for XON/XOFF. If you don't
  enable the flow control then you will probably overrun the modem's
  buffers and this will prove to be disastrous with vj header
  compression.



  10.2.	How do I use XON/XOFF for flow control?

  The better flow control is CTS/RTS. However, if you can not do the
  hardware flow control with the signals CTS and RTS, then use XON/XOFF.
  The following three steps need to be performed.


  o  You need to specify the pppd option xonxoff. This tells the pppd
     process to configure the serial device for XON/XOFF flow control
     and to load the two characters into the tty driver.

  o  You need to specify the XON and XOFF characters in the pppd
     parameter asyncmap. This tells the remote system that is should
     quote the XON and XOFF characters when it wishes to send them to
     you. It is normally specified as the pppd parameter `asyncmap
     a0000'.

  o  Of course, don't forget to tell the modem to use XON/XOFF flow
     control. My ZyXEL modem uses a sequence `&R1&H4' to do this.


  10.3.	The modem seems to always connect at a strange rate. When I use
  minicom, the modem will always use 14400. However, PPP is using 9600
  or 7200 or even 2400. How do I fix this?

  Put the desired rate as an option to the pppd process. If you don't
  put the rate, then pppd process will use whatever rate is set
  currently at the time. Not all programs will restore all of the
  parameters to the previous settings properly upon exit. This may lead
  to strange rates configured for the serial device.



  10.4.	The proxyarp function fails to find the hardware address.

  Use the ppp-2.1.2b.tar.gz package. The pppd process was erroneously
  compiled with the 1.1.8 kernel and it used Net-3 rather than Net-2
  definitions.

  Additionally, you should refer to the proxy-ARP mini-HOWTO about the
  requirements for using proxy-ARP.



  11.  Routing and other problems


  11.1.	My route to the remote keeps disappearing! It last for about 3
  minutes and then the route just goes away. Help!

  This is not a question for PPP.

  Hint: DON'T RUN routed!



  11.2.	I can reach the remote server, but I can not get anywhere else.

  Did you forget the `defaultroute' parameter to pppd? This parameter
  adds a default route into your routing system so that frames to all
  other IP addresses will be sent to the PPP device.

  The PPP software will not replace the default route if you have one
  already set when you run pppd. This is done to prevent people from
  destroying their default route to the ethernet routers by accident. A
  warning message is written to the system log if the defaultroute
  parameter is not performed for this reason.



  11.3.	I have a default route and I still can't get anywhere else! Now
  what?

  The problem then is not with the local Linux system. It most likely is
  routing problem on the remote end.

  The remote system is not configured for `IP forwarding'. It is an RFC
  requirement that this option NOT be enabled by default. You must
  enable the option. For Linux systems, you will need to build the
  kernel and specify that you want IP forwarding/gatewaying.

  The remote computers need a route back to you just as you need a route
  to them. This may be accomplished by one of four methods. Each has
  advantages and limitations. You need to do one and only one of these.


  o  Use a host route. At each host on the remote system, add a host
     route to your Linux IP address with the gateway being the terminal
     server that you use for your local access. This will work if you
     have a small number of host systems and a simple network without
     bridges, routers, gateways, etc.

  o  Use a network route. Subdivide the remote IP addresses so that your
     local Linux IP address and the remote terminal server address and
     the remote terminal server's ethernet address is on the same IP
     domain. This will work if you have the IP addresses to spare. It
     will work very well if you have a Class-B IP domain and can afford
     to put the all of the remote addresses on the same IP domain. Then
     add a network route on each of the gateways and routers so that any
     address of the remote network is sent to the terminal server. Most
     configurations have many hosts but few routers. (At sii.com, we
     have over 300 active host systems with only 3 routers.)

  o  Use gated on all of the gateways and on the terminal server. This
     will cause the terminal server to broadcast to the gateways that it
     can accept the frames for your IP address. Since the hosts will
     have a default route to one of the gateways, the gateways will
     generate the ICMP re-direct frame and the specific host will
     automatically add its host route.

  o  Use proxy ARP on the terminal server. This will only work if your
     remote IP address is in the same IP domain as one of the domains
     for the network cards.

  There is no clear solution. You must choose one of these.

  If your remote router requires to receive RIP frames in order to
  update the route to your system then you should use the bcastd program
  on sunsite.unc.edu. This will generate the RIP frames without actually
  running gated.



  11.4.	I can not ping my local IP address

  You are not able to do this because you don't have a route to the
  address. This is the normal operating environment. Don't try to ping
  the local IP address.

  If you wish to ping your own system then use the loopback address of
  127.0.0.1.

  You may be able to ping the remote address. However, some terminal
  servers may not allow this as the address may be 'phony' to them. It
  depends upon their environment.

  In general, don't try to ping either address. Choose a third address
  which is well known to be available on the remote network such as the
  name server IP address.



  12.  Interactions with other PPP implementations


  12.1.	I am using a Trumpet (for MSDOS) and the connection simply ter-
  minates. Why is this happening?

  Trumpet does not like any VJ header compression. Use the pppd option
  "-vj" to turn it off.



  12.2.	I am using dp-3.1.2 (with SunOS) and the system will not allow
  me to use anything but ping, or nslookup. Why is this happening?

  There is a bug in the 3.1.2 version of dp. Please get the 3.1.2a or
  later file from the dp ftp home site harbor.ecn.purdue.ecu. Until you
  can put the patch into dp, disable the vj header compression.



  12.3.	I can not connect to/with my Windows NT code (a.k.a. 'Daytona')

  Microsoft has chosen to support a non-standard authentication protocol
  with Windows NT. That is their right to do so provided that they have
  registered the protocol number with the IANA. (They have.)  If the
  `accept only Microsoft encrypted authentication' check box is set in
  the phone book entry, the connection will not complete. This setting
  mandates that the Daytona system only exchange PPP authentication with
  another Microsoft PPP implementation.

  Linux does not support this authentication protocol.

  If you have the option of changing the settings on the Daytona system
  then go to the Daytona Phone Book settings, advanced, security
  settings and choose either `Accept any authentication including clear
  text' to allow execution without authentication, or `Use clear text
  terminal login only' for PAP authentication, or `Accept only encrypted
  authentication' to allow CHAP authentication.

  The Microsoft authentication sequence is a PAP style authentication
  with their encryption algorithm for the passwords. Normal PAP sends
  the passwords in clear text. This would violate their C2 security
  goals.



  13.  Other messages written to the system log


  13.1.	Alarm

  This is not a problem. It means that a timer has expired and timers
  are a necessary part of the protocol establishment phase.



  13.2.	Unknown protocol (c025) received!.

  The remote wishes to exchange Link Quality Reporting protocol with the
  Linux system. This protocol is presently not supported. This is not an
  error. It is merely saying that it has received the request and will
  tell the remote that "I can't do this now. Don't bother me with this!"

  The Morning Star PPP package will always try to do LQR protocol. This
  is normal.



  13.3.	The connection fails with an ioctl(TIOCSCTTY) error.

  Use the ppp-2.1.2b.tar.gz package. This was a bug which was not caught
  before the `a' package was released.



  13.4.	The connection fails with errors "ioctl(TIOCGETD): I/O error"
  or "ioctl(PPPIOCSINPSIG): I/O error". What now?

  Look at the boot messages when you boot the kernel. If it says "PPP
  version 0.1.2" then you have an old version of the ppp.c driver.

  If it says "PPP version 0.2.7" then you have the current driver,
  however, it was not built with the same set of defines for the ioctl
  numbers. Ensure that you have only one file called "ppp.h". It should
  be located in the kernel's include/linux directory. Once you have done
  this, rebuild the kernel and the pppd process.



  13.5.	Sometimes the messages "ioctl(PPPIOCGDEBUG): I/O error",
  "ioctl(TIOCSETD): I/O error" and "ioctl(TIOCNXCL): I/O error" occur.
  Why?

  The remote system has disconnected the telephone. The tty drivers will
  re-establish the proper tty discipline and these errors are the result
  of the pppd process trying to do the same thing. These are to be
  expected.



  13.6.	My ifconfig has strange output for PPP.

  Usually the ifconfig program reports information similar to the
  following:



       ppp0	Link encap UNSPEC  HWaddr 00-00-00-00-00-00-00 ...
		 inet addr 192.76.32.2	P-t-P 129.67.1.65  Mask 255.255.255.0
		 UP POINTOPOINT RUNNING	MTU 1500  Metric 1




  The information is for display purposes only. If you are using a
  recent 1.2 kernel then update the nettools package with the current
  one on sunacm.swan.ac.uk in the directory
  /pub/Linux/networking/nettools.



  13.7.	The file /proc/net/dev seems to be empty

  Did you just issue the command "ls -l /proc/net" and are wondering why
  the size is zero?  If so, this is normal.  Instead, issue the command:

  cat /proc/net/dev

  You should not find the file empty. The size is always shown as zero,
  but that is the 'proc' file system. Don't believe the size. Do the
  command.

  The 'more', 'less', and 'most' programs may not be used to view the
  file directly. If you wish to use these programs, use it as follows:

  cat /proc/net/dev | less



  14.  Network routing issues (using PPP as a `cheap' bridge)


  14.1.	Slattach and ifconfig don't work like SLIP

  Do not use slattach and ifconfig with PPP. These are used for SLIP.
  The pppd process does these functions at the appropriate time. These
  must occur after the LCP and IPCP protocols have been exchanged.

  You can not replace pppd with slattach and ifconfig. Most of the
  protocol support for PPP is in the pppd process. Only the IP (and IPX
  when it is completed) processing is in the kernel.

  The host route to the remote system will be automatically added by
  pppd. There is no option to NOT add the route. The pppd process will
  terminate if the route could not be added.

  The default route may or may not be added. This is controlled by the
  option `defaultroute'. If you have a default route, it will not be
  changed.

  If you must do routing for an entire network, then put the route
  command into the /etc/ppp/ip-up script. The parameters to the script
  are:

     $0 - name of the script (/etc/ppp/ip-up or /etc/ppp/ip-down)
     $1 - name of the network device (such as ppp0)
     $2 - name of the tty device (such as /dev/cua0)
     $3 - speed of the tty device in Bits Per Second (such as 38400)
     $4 - the local IP address in dotted decimal notation
     $5 - the remote IP address in dotted decimal notation


  14.2.	I want the route to the network and not the route to the host.

  On sunsite there is a package called devinfo.tar.gz. It contains some
  useful little programs which will extract the data from the device and
  to do various things with the dotted IP addresses.

  The documentation is in the man pages in the file.

  For example, if you want to route the entire IP domain to the remote,
  the following may be used in /etc/ppp/ip-up.

  Of course, if the values are not variable, then simply use the
  appropriate entry in the route command.


  ______________________________________________________________________
  # Obtain the netmask for the ppp0 (or whatever) device
  NETMASK = `devinfo -d $1 -t mask`

  # Obtain the IP domain (without the host address by removing the extra bits)
  DOMAIN = `netmath -a $5 $NETMASK`

  # Do the network route now that the IP domain is known
  route -net add $DOMAIN gw $5
  ______________________________________________________________________




  15.  Other features and protocols


  15.1.	What about support for `demand dial'

  Use the diald package. This is on sunsite in the same directory as the
  ppp source, /pub/Linux/system/Network/serial.



  15.2.	What about `filtering'

  There are no plans to put filtering into the PPP code. Run the
  ipfirewall code. It is on sunsite. Help the author debug that code. It
  will do the filtering that you want in a general solution.

  The latest development kernels will include the patches to support
  filtering. (You will still need the ipfirewall code as the kernel only
  contains the patches which were in the ipfirewall code for the
  kernel.)  Again, filtering is a network issue and not one specifically
  for PPP.






  15.3.	How about IPX?

  The addition of support for IPX is fairly straight forward. Work is
  underway to include the IPX protocol.



  15.4.	How about NETBIOS?

  There is a netbios PPP protocol. However, your better solution would
  be to use TCP/IP and the `samba' code.

  Microsoft and others have used Netbios PPP protocol. This is usually a
  proprietary mixture and one vendor is not guaranteed to work with
  another.

  I'll leave the Netbios protocols for someone else. If a Microsoft
  employee wishes to donate to the public domain the specifications and
  the time to implement their Netbios over PPP, send the diffs to me.
  I'll make sure that they are put into the released product.



  15.5.	I need ISDN support. Is there any?

  ISDN support revolves around having a working ISDN driver. The present
  design of the ppp driver does not lend itself well to the concept of a
  block of data being received. This is being changed. A driver for the
  Sonix interface is being developed.



  15.6.	How about just standard synchronous PPP?

  There are small changes needed to support a serial interface which
  uses synchronous communications. The redesign of the ppp driver will
  help with this function as well. Kate Marika Alhola has expressed an
  intrest in writing such a synchronous driver for her hardware. You
  should contact her at kate@digiw.fi for further information.



  16.  Miscallenous


  16.1.	Do you have a PPP compatible mail reader?

  Huh?	You have the wrong group if you want MSDOS. PPP has nothing to
  do with the mail user agent. All of the mail agents are compatible
  with PPP.



  16.2.	How about a news reader?

  Refer to the previous answer.










