This is the README file for ppp-2.5, a package which implements the Point-to-Point Protocol (PPP) to provide Internet connections over serial lines and other types of links which can be considered to be point-to-point links.
Introduction.
The Point-to-Point Protocol (PPP) provides a standard way to establish a network connection over a serial link. At present, this package supports IP and IPV6 and the protocols layered above them, such as TCP and UDP.
This PPP implementation consists of two parts:
Kernel code, which establishes a network interface and passes packets between the serial port, the kernel networking code and the PPP daemon (pppd). This code is implemented using STREAMS modules on Solaris, and as a line discipline under Linux.
The PPP daemon (pppd), which negotiates with the peer to establish the link and sets up the ppp network interface. Pppd includes support for authentication, so you can control which other systems may make a PPP connection and what IP addresses they may use.
The platforms supported by this package are Linux and Solaris. (There is also code to support various old flavours of Unix in the git repository, but it is quite old and unmaintained.)
The kernel code for Linux is no longer distributed with this package, since the relevant kernel code is in the official Linux kernel source (and has been for many years) and is included in all reasonably modern Linux distributions. The Linux kernel code supports using PPP over things other than serial ports, such as PPP over Ethernet and PPP over ATM.
Installation.
The file SETUP contains general information about setting up your system for using PPP. There is also a README file for each supported system, which contains more specific details for installing PPP on that system. The supported systems, and the corresponding README files, are:
Linux README.linux
Solaris README.sol2In each case you start by running the ./configure script. This works
out which operating system you are using and creates the appropriate
makefiles. You then run make' to compile the user-level code, and (as root)make install' to install the user-level programs pppd, chat
and pppstats.
N.B. Since 2.3.0, leaving the permitted IP addresses column of the pap-secrets or chap-secrets file empty means that no addresses are permitted. You need to put a "*" in that column to allow the peer to use any IP address. (This only applies where the peer is authenticating itself to you, of course.)
What's new in ppp-2.5.1
The files copied to /etc/ppp (or
Pppd can now measure and log the round-trip time (RTT) of LCP echo-requests and record them in a binary file structured as a circular buffer. Other programs or scripts can examine the file and provide real-time statistics on link latency. This is enabled by a new "lcp-rtt-file" option.
New scripts net-init, net-pre-up and net-down are executed in the process of bringing the network interface up and down. They provide additional, more deterministic ways for pppd to interact with the rest of the networking configuration.
New options have been added to allow the system administrator to set the location of various scripts and secrets files.
A new "noresolvconf" option tells pppd not to write the /etc/ppp/resolv.conf file; DNS server addresses, if obtained from the peer, are still passed to scripts in the environment.
Pppd will now create the directory for the TDB connection database if it doesn't already exist.
Kernel module code for Solaris is no longer included.
Support for decompressing compressed packets has been removed from pppdump, because the zlib code used was old and potentially vulnerable.
Some old code has been removed.
Various other bug fixes and minor enhancements.
What was new in ppp-2.5.0.
The 2.5.0 release is a major release of pppd which contains breaking changes for third-party plugins, a complete revamp of the build-system and that allows for flexibility of configuring features as needed.
In Summary:
Note that if you have built and installed previous versions of this package and you want to continue having configuration and TDB files in /etc/ppp, you will need to use the --sysconfdir option to ./configure.
For a list of the changes made during the 2.4 series releases of this package, see the Changes-2.4 file.
Compression methods.
This package supports two packet compression methods: Deflate and BSD-Compress. Other compression methods which are in common use include Predictor, LZS, and MPPC. These methods are not supported for two reasons - they are patent-encumbered, and they cause some packets to expand slightly, which pppd doesn't currently allow for. BSD-Compress and Deflate (which uses the same algorithm as gzip) don't ever expand packets.
Contacts.
Most communication relating to this package happens on github at https://github.com/ppp-project/ppp/. The linux-ppp@vger.kernel.org mailing list also exists and can be used.
If you find bugs in this package, the best thing to do is to create an issue on github. If you can't or don't want to do that, you can post to linux-ppp@vger.kernel.org, or report them to the maintainer for the port for the operating system you are using:
Linux Paul Mackerras paulus@ozlabs.org Solaris James Carlson carlson@workingcode.com
Copyrights:
All of the code can be freely used and redistributed. The individual source files each have their own copyright and permission notice. Pppd, pppstats and pppdump are under BSD-style notices. Some of the pppd plugins are GPL'd. Chat has an MIT licence notice.
Distribution:
The primary site for releases of this software is:
ftp://ftp.samba.org/pub/ppp/