PPPD is the Point-to-Point Protocol

daemon Daimon or Daemon (Ancient Greek: , "god", "godlike", "power", "fate") originally referred to a lesser deity or guiding spirit such as the daimons of ancient Greek religion and mythology and of later Hellenistic religion and philosophy. The wo ...

which is used to manage network connections between two nodes on

Unix-like A Unix-like (sometimes referred to as UN*X or *nix) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-li ...

operating systems An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

. It is configured using

command-line A command-line interpreter or command-line processor uses a command-line interface (CLI) to receive command (computing), commands from a user in the form of lines of text. This provides a means of setting parameters for the environment, invokin ...

arguments and

configuration file In computing, configuration files (commonly known simply as config files) are files used to configure the parameters and initial settings for some computer programs. They are used for user applications, server processes and operating system ...

s. While it has initially been used to manage only

dial-up access Dial-up Internet access is a form of Internet access that uses the facilities of the public switched telephone network (PSTN) to establish a connection to an Internet service provider (ISP) by dialing a telephone number on a conventional telepho ...

, it is also used to manage

broadband In telecommunications, broadband is wide bandwidth data transmission which transports multiple signals at a wide range of frequencies and Internet traffic types, that enables messages to be sent simultaneously, used in fast internet connections. ...

connections such as

DSL Digital subscriber line (DSL; originally digital subscriber loop) is a family of technologies that are used to transmit digital data over telephone lines. In telecommunications marketing, the term DSL is widely understood to mean asymmetric dig ...

, if

Point-to-Point Protocol over Ethernet The Point-to-Point Protocol over Ethernet (PPPoE) is a network protocol for encapsulating Point-to-Point Protocol (PPP) frames inside Ethernet frames. It appeared in 1999, in the context of the boom of DSL as the solution for tunneling pack ...

(PPPoE) or

Point-to-Point Protocol over ATM In computer networking, the Point-to-Point Protocol over ATM (PPPoA) is a layer 2 data-link protocol typically used to connect domestic broadband modems to ISPs via phone lines. It is used mainly with DOCSIS and DSL carriers, by encapsulating PPP ...

(PPPoA) is used. The role of pppd is managing PPP session establishment and session termination. During session establishment, pppd has the role of: * Looped link detection: PPP detects looped links using magic numbers. When PPPD sends PPP LCP messages, these messages include a magic number. If a line is looped, the node receives an LCP message with its own magic number, instead of getting a message with the peer's magic number. *Automatic self configuration: Using

Link Control Protocol In computer networking, the Link Control Protocol (LCP) forms part of the Point-to-Point Protocol (PPP), within the family of Internet protocols. In setting up PPP communications, both the sending and receiving devices send out LCP packets to dete ...

it has to negotiate protocol features like Address-and-Control-Field-Compression (ACFC), escaped characters, and the compression, encryption (like MPPE) and authentication methods to use. *Access control and authentication: Using protocols like

Challenge-handshake authentication protocol In computing, the Challenge-Handshake Authentication Protocol (CHAP) is an authentication protocol originally used by Point-to-Point Protocol (PPP) to validate users. CHAP is also carried in other authentication protocols such as RADIUS and Diamet ...

(CHAP) or

Password authentication protocol Password Authentication Protocol (PAP) is a password-based authentication protocol used by Point-to-Point Protocol (PPP) to validate users. PAP is specified in . Almost all network operating systems support PPP with PAP, as do most network access ...

(PAP) it has to provide and check authentication data. *Layer 3 configuration: If using

Internet Protocol Control Protocol In computer networking, Internet Protocol Control Protocol (IPCP) is a Network Control Protocol (NCP) for establishing and configuring Internet Protocol over a Point-to-Point Protocol link. IPCP is responsible for configuring the IP addresses as w ...

(IPCP), it will negotiate or determine IP parameters such as the

IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network that uses the Internet Protocol for communication.. Updated by . An IP address serves two main functions: network interface ident ...

es, the

maximum transmission unit In computer networking, the maximum transmission unit (MTU) is the size of the largest protocol data unit (PDU) that can be communicated in a single network layer transaction. The MTU relates to, but is not identical to the maximum frame size th ...

, and

name server A name server refers to the server component of the Domain Name System (DNS), one of the two principal namespaces of the Internet. The most important function of DNS servers is the translation (resolution) of human-memorable domain names (example. ...

addresses. Some versions may also support

Internetwork Packet Exchange Control Protocol Internetworking is the practice of interconnecting multiple computer networks, such that any pair of hosts in the connected networks can exchange messages irrespective of their hardware-level networking technology. The resulting system of interco ...

(IPXCP) and

AppleTalk Control Protocol AppleTalk is a discontinued proprietary suite of networking protocols developed by Apple Computer for their Macintosh computers. AppleTalk includes a number of features that allow local area networks to be connected with no prior setup or the ...

(ATCP) for routing

IPX Internetwork Packet Exchange (IPX) is the network layer protocol in the IPX/SPX protocol suite. IPX is derived from Xerox Network Systems' IDP. It also has the ability to act as a transport layer protocol. The IPX/SPX protocol suite was very po ...

AppleTalk AppleTalk is a discontinued proprietary suite of networking protocols developed by Apple Computer for their Macintosh computers. AppleTalk includes a number of features that allow local area networks to be connected with no prior setup or the ...

over the link. *After negotiation is complete, it has to set up the required network interfaces and routes, so that the connection is run by the

kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine lea ...

. pppd terminates a PPP link when: * too many frames with invalid

frame check sequence A frame check sequence (FCS) is an error-detecting code added to a frame in a communication protocol. Frames are used to send payload data from a source to a destination. Purpose All frames and the bits, bytes, and fields contained with ...

(FCS) field have been received * the link is considered "idle" (if configured) * another program or the peer requests link termination. Some newer versions of pppd are also capable of handling

Dial-on-demand routing Dial on Demand Routing (DDR) is a routing technique where a network connection to a remote site is established only when needed. In other words, if the router tries to send out data and the connection is off, then the router will automatically esta ...

, where pppd sets up a virtual network, captures the packages it receives and establishes a PPP connection and forwards the captured and not-yet transmitted packages over the link.

Frontends and configurators

kppp WvDial (pronounced 'weave-dial') is a utility that helps in making modem-based connections to the Internet that is included in some Linux distributions. WvDial is a Point-to-Point Protocol dialer: it dials a modem and starts pppd in order to conn ...

– A kde

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

frontend for pppd. * gnome-ppp – A gnome

frontend for pppd. * pppconfig – It uses the standard ppp configuration files and sets ppp up so that the standard pon and poff commands (to connect and disconnect) and plog (to list the log) can be used to control ppp. It includes modem detection. *

wvdial WvDial (pronounced 'weave-dial') is a utility that helps in making modem-based connections to the Internet that is included in some Linux distributions. WvDial is a Point-to-Point Protocol dialer: it dials a modem and starts pppd in order to co ...

– A

CLI CLI may refer to: Computing * Call Level Interface, an SQL database management API * Command-line interface, of a computer program * Command-line interpreter or command language interpreter; see List of command-line interpreters * CLI (x86 instru ...

tool which is used for modem initialisation before starting pppd.

References

Manual page A man page (short for manual page) is a form of software documentation usually found on a Unix or Unix-like operating system. Topics covered include computer programs (including library and system calls), formal standards and conventions, and ev ...

: pppd(8) (''man pppd'' in a

Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

terminal Terminal may refer to: Computing Hardware * Terminal (electronics), a device for joining electrical circuits together * Terminal (telecommunication), a device communicating over a line * Computer terminal, a set of primary input and output devic ...

o
pppd man page at ppp.samba.org
.

External links

RP-PPPoE
a PPPoE client, server and relay implementation for Linux.
ACCEL-PPP
high performance PPTP/L2TP/PPPoE/IPoE server for Linux. * {{Freshmeat, pppd, pppd
Apple ppp source
Free network-related software Unix network-related software

Frontends and configurators

References

Further reading

External links