Linux PPP FAQ: General information

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## 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 base 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 choose not to use slirp, 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.

In addition to TIA, Danny Gasparovski wrote a program called slirp which will perform functions similar to TIA. The program is currently available with the source code from the ftp site blitzen.canberra.edu.au:/pub/slirp. You should obtain the code if you wish additional information about this program. From the initial examination, it is seems to be an excellent contender to the commercial TIA program.

## 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.

The second part is the \daemon\ process, pppd. This is a required process. The source to it is in the file ppp-2.2.0e.tar.gz located on sunsite.unc.edu in the /pub/Linux/system/Network/serial directory.

Version 2.2 and above are designed to be used only with the 1.2 and later kernels. Please don't use this version with the 1.1 series kernels as they are out of date for either the tty driver or the networking software.

## 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 are additional sources of information for PPP?

(Where\s the documentation? Is there a HOWTO?, etc.)

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

- The README file in the source package.
- The README.linux file in the source package.
- The Net-2-HOWTO document.
- The PPP-HOWTO document.
- The Network Administration Guide.
- The pppd man page.
- The FAQ document for the comp.protocols.ppp newsgroup.

The HOWTO and this FAQ are 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 /pub/Linux/docs/LPD/network-guide directory on sunsite. It is also 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 FAQ for comp.protocols.ppp 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 Would someone please send me scripts for PPP so that I may see how they are written?

There are a few scripts which are included with the source package for pppd. It will cover the normal types of access where you are requested to enter a UNIX login and password.

Specific \scripts\ for specific systems are not included. If you have problems with a specific connection then you should contact the help desk for your site, the local news group at the site, or the general usenet groups for Linux. Unfortunately, time does not permit me to answer questions for help on supplying a script for your specific system.

## 2.7 Where should I post questions about PPP?

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

Questions such as \Why wont pppd compile?\ are generally linux related and belong on the comp.os.linux.networking group.

Please don't use comp.os.linux.help even if your site should still carry this obsolete news group.

## 2.8 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 31\ 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 \local2\ group which come from the pppd process.

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

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