-.\" manual page [] for pppd 2.0
-.\" $Id: pppd.8,v 1.1 1994/02/08 05:24:41 paulus Exp $
+.\" manual page [] for pppd 2.4
+.\" $Id: pppd.8,v 1.90 2008/03/26 12:09:40 paulus Exp $
.\" SH section heading
.\" SS subsection heading
.\" LP paragraph
.\" IP indented paragraph
.\" TP hanging label
+.\"
+.\" Copyright (c) 1993-2003 Paul Mackerras <paulus@samba.org>
+.\"
+.\" Permission to use, copy, modify, and distribute this software for any
+.\" purpose with or without fee is hereby granted, provided that the above
+.\" copyright notice and this permission notice appear in all copies.
+.\"
+.\" THIS SOFTWARE IS PROVIDED "AS IS" AND THE AUTHORS DISCLAIM ALL WARRANTIES
+.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.\"
.TH PPPD 8
.SH NAME
-pppd \- Point to Point Protocol daemon
+pppd \- Point-to-Point Protocol Daemon
.SH SYNOPSIS
.B pppd
[
.I options
-] [
-.I tty_name
-] [
-.I speed
]
.SH DESCRIPTION
.LP
-The Point-to-Point Protocol (PPP) provides a method for transmitting
-datagrams over serial point-to-point links. PPP
-is composed of three parts: a method for encapsulating datagrams over
-serial links, an extensible Link Control Protocol (LCP), and
-a family of Network Control Protocols (NCP) for establishing
-and configuring different network-layer protocols.
-.LP
-The encapsulation scheme is provided by driver code in the kernel.
-.B pppd
-provides the basic LCP, authentication support, and an
-NCP for establishing and configuring the Internet Protocol (IP)
-(called the IP Control Protocol, IPCP).
+PPP is the protocol used for establishing internet links over dial-up
+modems, DSL connections, and many other types of point-to-point
+links. The \fIpppd\fR daemon works together with the kernel PPP
+driver to establish and maintain a PPP link with another system
+(called the \fIpeer\fR) and to negotiate Internet Protocol (IP)
+addresses for each end of the link. Pppd can also authenticate the
+peer and/or supply authentication information to the peer. PPP can be
+used with other network protocols besides IP, but such use is becoming
+increasingly rare.
.SH FREQUENTLY USED OPTIONS
.TP
-.I <tty_name>
-Communicate over the named device. The string "/dev/"
-is prepended if necessary. If no device name is given,
-.I pppd
-will use the controlling terminal, and will not fork to put itself in
-the background.
-.TP
-.I <speed>
-Set the baud rate to <speed>. On systems such as 4.4BSD and NetBSD,
-any speed can be specified. Other systems (e.g. SunOS) allow only a
-limited set of speeds.
-.TP
-.B asyncmap \fI<map>
-Set the async character map to <map>.
-This map describes which control characters cannot be successfully
-received over the serial line.
-.I pppd
-will ask the peer to send these characters as a 2-byte "escape" sequence.
-The argument is a 32 bit hex number
-with each bit representing a character to escape.
-Bit 0 (00000001) represents the character 0x00;
-bit 31 (80000000) represents the character 0x1f or ^_.
-The default asyncmap is 0. If multiple \fBasyncmap\fR options are
-given, the values are ORed together.
+.I ttyname
+Use the serial port called \fIttyname\fR to communicate with the
+peer. If \fIttyname\fR does not begin with a slash (/),
+the string "/dev/" is prepended to \fIttyname\fR to form the
+name of the device to open. If no device name is given, or if the
+name of the terminal
+connected to the standard input is given, pppd will use that terminal,
+and will not fork to put itself in the background. A value for this
+option from a privileged source cannot be overridden by a
+non-privileged user.
+.TP
+.I speed
+An option that is a decimal number is taken as the desired baud rate
+for the serial device. On systems such as
+4.4BSD and NetBSD, any speed can be specified. Other systems
+(e.g. Linux, SunOS) only support the commonly-used baud rates.
+.TP
+.B asyncmap \fImap
+This option sets the Async-Control-Character-Map (ACCM) for this end
+of the link. The ACCM is a set of 32 bits, one for each of the
+ASCII control characters with values from 0 to 31, where a 1 bit
+indicates that the corresponding control character should not be used
+in PPP packets sent to this system. The map is encoded as a
+hexadecimal number (without a leading 0x) where the least significant
+bit (00000001) represents character 0 and the most significant bit
+(80000000) represents character 31.
+Pppd will ask the peer to send these characters as a 2-byte
+escape sequence.
+If multiple \fIasyncmap\fR options are given, the values are ORed
+together. If no \fIasyncmap\fR option is given, the default is zero,
+so pppd will ask the peer not to escape any control characters.
+To escape transmitted characters, use the \fIescape\fR option.
.TP
.B auth
Require the peer to authenticate itself before allowing network
-packets to be sent or received.
-.TP
-.B connect \fI<p>
-Use the executable or shell command specified by <p> to set up the
-serial line. This script would typically use the "chat" program to
-dial the modem and start the remote ppp session.
+packets to be sent or received. This option is the default if the
+system has a default route. If neither this option nor the
+\fInoauth\fR option is specified, pppd will only allow the peer to use
+IP addresses to which the system does not already have a route.
+.TP
+.B call \fIname
+Read additional options from the file /etc/ppp/peers/\fIname\fR. This
+file may contain privileged options, such as \fInoauth\fR, even if pppd
+is not being run by root. The \fIname\fR string may not begin with /
+or include .. as a pathname component. The format of the options file
+is described below.
+.TP
+.B connect \fIscript
+Usually there is something which needs to be done to prepare the link
+before the PPP protocol can be started; for instance, with a dial-up
+modem, commands need to be sent to the modem to dial the appropriate
+phone number. This option specifies an command for pppd to execute
+(by passing it to a shell) before attempting to start PPP negotiation.
+The chat (8) program is often useful here, as it provides a way to
+send arbitrary strings to a modem and respond to received characters.
+A value
+for this option from a privileged source cannot be overridden by a
+non-privileged user.
.TP
.B crtscts
-Use hardware flow control (i.e. RTS/CTS) to control the flow of data on
-the serial port.
+Specifies that pppd should set the serial port to use hardware flow
+control using the RTS and CTS signals in the RS-232 interface.
+If neither the \fIcrtscts\fR, the
+\fInocrtscts\fR, the \fIcdtrcts\fR nor the \fInocdtrcts\fR option
+is given, the hardware flow control setting for the serial port is
+left unchanged.
+Some serial ports (such as Macintosh serial ports) lack a true
+RTS output. Such serial ports use this mode to implement
+unidirectional flow control. The serial port will
+suspend transmission when requested by the modem (via CTS)
+but will be unable to request the modem to stop sending to the
+computer. This mode retains the ability to use DTR as
+a modem control line.
.TP
.B defaultroute
Add a default route to the system routing tables, using the peer as
the gateway, when IPCP negotiation is successfully completed.
-This entry is removed when the PPP connection is broken.
-.TP
-.B file \fI<f>
-Read options from file <f> (the format is described below).
-.TP
-.B mru \fI<n>
-Set the MRU [Maximum Receive Unit] value to <n> for negotiation.
-.I pppd
-will ask the peer to send packets of no more than <n> bytes.
- The minimum MRU value is 128.
-The default MRU value is 1500. A value of 296 is recommended for slow
-links (40 bytes for TCP/IP header + 256 bytes of data).
-.TP
-.B netmask \fI<n>
-Set the interface netmask to <n>, a 32 bit netmask in "decimal dot" notation
-(e.g. 255.255.255.0).
+This entry is removed when the PPP connection is broken. This option
+is privileged if the \fInodefaultroute\fR option has been specified.
+.TP
+.B disconnect \fIscript
+Execute the command specified by \fIscript\fR, by passing it to a
+shell, after
+pppd has terminated the link. This command could, for example, issue
+commands to the modem to cause it to hang up if hardware modem control
+signals were not available. The disconnect script is not run if the
+modem has already hung up. A value for this option from a privileged
+source cannot be overridden by a non-privileged user.
+.TP
+.B escape \fIxx,yy,...
+Specifies that certain characters should be escaped on transmission
+(regardless of whether the peer requests them to be escaped with its
+async control character map). The characters to be escaped are
+specified as a list of hex numbers separated by commas. Note that
+almost any character can be specified for the \fIescape\fR option,
+unlike the \fIasyncmap\fR option which only allows control characters
+to be specified. The characters which may not be escaped are those
+with hex values 0x20 - 0x3f or 0x5e.
+.TP
+.B file \fIname
+Read options from file \fIname\fR (the format is described below).
+The file must be readable by the user who has invoked pppd.
+.TP
+.B init \fIscript
+Execute the command specified by \fIscript\fR, by passing it to a shell, to
+initialize the serial line. This script would typically use the
+chat(8) program to configure the modem to enable auto answer. A value
+for this option from a privileged source cannot be overridden by a
+non-privileged user.
+.TP
+.B lock
+Specifies that pppd should create a UUCP-style lock file for the
+serial device to ensure exclusive access to the device. By default,
+pppd will not create a lock file.
+.TP
+.B mru \fIn
+Set the MRU [Maximum Receive Unit] value to \fIn\fR. Pppd
+will ask the peer to send packets of no more than \fIn\fR bytes.
+The value of \fIn\fR must be between 128 and 16384; the default is 1500.
+A value of
+296 works well on very slow links (40 bytes for TCP/IP header + 256
+bytes of data).
+Note that for the IPv6 protocol, the MRU must be at least 1280.
+.TP
+.B mtu \fIn
+Set the MTU [Maximum Transmit Unit] value to \fIn\fR. Unless the
+peer requests a smaller value via MRU negotiation, pppd will
+request that the kernel networking code send data packets of no more
+than \fIn\fR bytes through the PPP network interface. Note that for
+the IPv6 protocol, the MTU must be at least 1280.
.TP
.B passive
-Enables the "passive" option in the LCP. With this option,
-.I pppd
-will attempt to initiate a connection; if no reply is received from
-the peer,
-.I pppd
-will then just wait passively for a valid LCP packet from the peer
-(instead of exiting, as it does without this option).
-.TP
-.B silent
-With this option,
-.I pppd
-will not transmit LCP packets to initiate a connection until a valid
-LCP packet is received from the peer (as for the "passive" option with
-old versions of \fIpppd\fR).
+Enables the "passive" option in the LCP. With this option, pppd will
+attempt to initiate a connection; if no reply is received from the
+peer, pppd will then just wait passively for a valid LCP packet from
+the peer, instead of exiting, as it would without this option.
.SH OPTIONS
.TP
.I <local_IP_address>\fB:\fI<remote_IP_address>
Set the local and/or remote interface IP addresses. Either one may be
omitted. The IP addresses can be specified with a host name or in
-"decimal dot" notation (e.g. "150.203.23.247"). The default local
-address is the (first) IP address of the system. The remote address
-will be obtained from the peer if not specified in any option. Thus,
-in simple cases, this option is not required.
-.TP
-.B -all
-Don't request or allow negotiation of any options for LCP and IPCP (use
-default values).
-.TP
-.B -ac
-Disable Address/Control compression negotiation (use default, i.e.
-disabled).
-.TP
-.B -am
-Disable asyncmap negotiation (use default, i.e. 0xffffffff).
-.TP
-.B -as \fI<n>
-Same as
-.B asyncmap \fI<n>
-.TP
-.B -d
-Increase debugging level.
-.TP
-.B -detach
-Don't fork to become a background process (otherwise
-.I pppd
-will do so if a serial device is specified).
-.TP
-.B -ip
-Disable IP address negotiation (with this option, the remote IP
-address must be specified with an option on the command line or in an
-options file).
-.TP
-.B -mn
-Disable magic number negotiation. With this option,
-.I pppd
-cannot detect a looped-back line.
-.TP
-.B -mru
-Disable MRU [Maximum Receive Unit] negotiation (use default, i.e. 1500).
-.TP
-.B -p
-Same as the
-.B passive
-option.
-.TP
-.B -pc
-Disable protocol field compression negotiation (use default, i.e. disabled).
-.TP
-.B +ua \fI<p>
-Agree to authenticate using PAP [Password Authentication Protocol] if
-requested by the peer, and
-use the data in file <p> for the user and password to send to the
-peer. The file contains the remote user name, followed by a newline,
-followed by the remote password, followed by a newline. This option
-is obsolescent.
+decimal dot notation (e.g. 150.234.56.78). The default local
+address is the (first) IP address of the system (unless the
+\fInoipdefault\fR
+option is given). The remote address will be obtained from the peer
+if not specified in any option. Thus, in simple cases, this option is
+not required. If a local and/or remote IP address is specified with
+this option, pppd
+will not accept a different value from the peer in the IPCP
+negotiation, unless the \fIipcp\-accept\-local\fR and/or
+\fIipcp\-accept\-remote\fR options are given, respectively.
+.TP
+.B +ipv6
+Enable the IPv6CP and IPv6 protocols.
+.TP
+.B ipv6 \fI<local_interface_identifier>\fR,\fI<remote_interface_identifier>
+Set the local and/or remote 64-bit interface identifier. Either one may be
+omitted. The identifier must be specified in standard ASCII notation of
+IPv6 addresses (e.g. ::dead:beef). If the
+\fIipv6cp\-use\-ipaddr\fR
+option is given, the local identifier is the local IPv4 address (see above).
+On systems which supports a unique persistent id, such as EUI\-48 derived
+from the Ethernet MAC address, \fIipv6cp\-use\-persistent\fR option can be
+used to replace the \fIipv6 <local>,<remote>\fR option. Otherwise the
+identifier is randomized.
+.TP
+.B active\-filter \fIfilter\-expression
+Specifies a packet filter to be applied to data packets to determine
+which packets are to be regarded as link activity, and therefore reset
+the idle timer, or cause the link to be brought up in demand-dialling
+mode. This option is useful in conjunction with the
+\fBidle\fR option if there are packets being sent or received
+regularly over the link (for example, routing information packets)
+which would otherwise prevent the link from ever appearing to be idle.
+The \fIfilter\-expression\fR syntax is as described for tcpdump(1),
+except that qualifiers which are inappropriate for a PPP link, such as
+\fBether\fR and \fBarp\fR, are not permitted. Generally the filter
+expression should be enclosed in single-quotes to prevent whitespace
+in the expression from being interpreted by the shell. This option
+is currently only available under Linux, and requires that the kernel
+was configured to include PPP filtering support (CONFIG_PPP_FILTER).
+Note that it
+is possible to apply different constraints to incoming and outgoing
+packets using the \fBinbound\fR and \fBoutbound\fR qualifiers.
+.TP
+.B allow\-ip \fIaddress(es)
+Allow peers to use the given IP address or subnet without
+authenticating themselves. The parameter is parsed as for each
+element of the list of allowed IP addresses in the secrets files (see
+the AUTHENTICATION section below).
+.TP
+.B allow\-number \fInumber
+Allow peers to connect from the given telephone number. A trailing
+`*' character will match all numbers beginning with the leading part.
+.TP
+.B bsdcomp \fInr,nt
+Request that the peer compress packets that it sends, using the
+BSD-Compress scheme, with a maximum code size of \fInr\fR bits, and
+agree to compress packets sent to the peer with a maximum code size of
+\fInt\fR bits. If \fInt\fR is not specified, it defaults to the value
+given for \fInr\fR. Values in the range 9 to 15 may be used for
+\fInr\fR and \fInt\fR; larger values give better compression but
+consume more kernel memory for compression dictionaries.
+Alternatively, a value of 0 for \fInr\fR or \fInt\fR disables
+compression in the corresponding direction. Use \fInobsdcomp\fR or
+\fIbsdcomp 0\fR to disable BSD-Compress compression entirely.
+.TP
+.B cdtrcts
+Use a non-standard hardware flow control (i.e. DTR/CTS) to control
+the flow of data on the serial port. If neither the \fIcrtscts\fR,
+the \fInocrtscts\fR, the \fIcdtrcts\fR nor the \fInocdtrcts\fR
+option is given, the hardware flow control setting for the serial
+port is left unchanged.
+Some serial ports (such as Macintosh serial ports) lack a true
+RTS output. Such serial ports use this mode to implement true
+bi-directional flow control. The sacrifice is that this flow
+control mode does not permit using DTR as a modem control line.
+.TP
+.B chap\-interval \fIn
+If this option is given, pppd will rechallenge the peer every \fIn\fR
+seconds.
+.TP
+.B chap\-max\-challenge \fIn
+Set the maximum number of CHAP challenge transmissions to \fIn\fR
+(default 10).
.TP
-.B +pap
-Require the peer to authenticate itself using PAP.
+.B chap\-restart \fIn
+Set the CHAP restart interval (retransmission timeout for challenges)
+to \fIn\fR seconds (default 3).
+.TP
+.B child\-timeout \fIn
+When exiting, wait for up to \fIn\fR seconds for any child processes
+(such as the command specified with the \fBpty\fR command) to exit
+before exiting. At the end of the timeout, pppd will send a SIGTERM
+signal to any remaining child processes and exit. A value of 0 means
+no timeout, that is, pppd will wait until all child processes have
+exited.
+.TP
+.B connect\-delay \fIn
+Wait for up to \fIn\fR milliseconds after the connect script finishes for
+a valid PPP packet from the peer. At the end of this time, or when a
+valid PPP packet is received from the peer, pppd will commence
+negotiation by sending its first LCP packet. The default value is
+1000 (1 second). This wait period only applies if the \fBconnect\fR
+or \fBpty\fR option is used.
.TP
-.B -pap
-Don't agree to authenticate using PAP.
+.B debug
+Enables connection debugging facilities.
+If this option is given, pppd will log the contents of all
+control packets sent or received in a readable form. The packets are
+logged through syslog with facility \fIdaemon\fR and level
+\fIdebug\fR. This information can be directed to a file by setting up
+/etc/syslog.conf appropriately (see syslog.conf(5)).
+.TP
+.B default\-asyncmap
+Disable asyncmap negotiation, forcing all control characters to be
+escaped for both the transmit and the receive direction.
+.TP
+.B default\-mru
+Disable MRU [Maximum Receive Unit] negotiation. With this option,
+pppd will use the default MRU value of 1500 bytes for both the
+transmit and receive direction.
+.TP
+.B deflate \fInr,nt
+Request that the peer compress packets that it sends, using the
+Deflate scheme, with a maximum window size of \fI2**nr\fR bytes, and
+agree to compress packets sent to the peer with a maximum window size
+of \fI2**nt\fR bytes. If \fInt\fR is not specified, it defaults to
+the value given for \fInr\fR. Values in the range 9 to 15 may be used
+for \fInr\fR and \fInt\fR; larger values give better compression but
+consume more kernel memory for compression dictionaries.
+Alternatively, a value of 0 for \fInr\fR or \fInt\fR disables
+compression in the corresponding direction. Use \fInodeflate\fR or
+\fIdeflate 0\fR to disable Deflate compression entirely. (Note: pppd
+requests Deflate compression in preference to BSD-Compress if the peer
+can do either.)
+.TP
+.B demand
+Initiate the link only on demand, i.e. when data traffic is present.
+With this option, the remote IP address may be specified by the user
+on the command line or in an options file, or if not, pppd will use
+an arbitrary address in the 10.x.x.x range. Pppd will initially
+configure the interface and enable it for IP traffic without
+connecting to the peer. When traffic is available, pppd will
+connect to the peer and perform negotiation, authentication, etc.
+When this is completed, pppd will commence passing data packets
+(i.e., IP packets) across the link.
+
+The \fIdemand\fR option implies the \fIpersist\fR option. If this
+behaviour is not desired, use the \fInopersist\fR option after the
+\fIdemand\fR option. The \fIidle\fR and \fIholdoff\fR
+options are also useful in conjunction with the \fIdemand\fR option.
+.TP
+.B domain \fId
+Append the domain name \fId\fR to the local host name for authentication
+purposes. For example, if gethostname() returns the name porsche, but
+the fully qualified domain name is porsche.Quotron.COM, you could
+specify \fIdomain Quotron.COM\fR. Pppd would then use the name
+\fIporsche.Quotron.COM\fR for looking up secrets in the secrets file,
+and as the default name to send to the peer when authenticating itself
+to the peer. This option is privileged.
+.TP
+.B dryrun
+With the \fBdryrun\fR option, pppd will print out all the option
+values which have been set and then exit, after parsing the command
+line and options files and checking the option values, but before
+initiating the link. The option values are logged at level info, and
+also printed to standard output unless the device on standard output
+is the device that pppd would be using to communicate with the peer.
+.TP
+.B dump
+With the \fBdump\fR option, pppd will print out all the option values
+which have been set. This option is like the \fBdryrun\fR option
+except that pppd proceeds as normal rather than exiting.
+.TP
+.B enable-session
+Enables session accounting via PAM or wtwp/wtmpx, as appropriate.
+When PAM is enabled, the PAM "account" and "session" module stacks
+determine behavior, and are enabled for all PPP authentication
+protocols. When PAM is disabled, wtmp/wtmpx entries are recorded
+regardless of whether the peer name identifies a valid user on the
+local system, making peers visible in the last(1) log. This feature
+is automatically enabled when the pppd \fBlogin\fR option is used.
+Session accounting is disabled by default.
+.TP
+.B endpoint \fI<epdisc>
+Sets the endpoint discriminator sent by the local machine to the peer
+during multilink negotiation to \fI<epdisc>\fR. The default is to use
+the MAC address of the first ethernet interface on the system, if any,
+otherwise the IPv4 address corresponding to the hostname, if any,
+provided it is not in the multicast or locally-assigned IP address
+ranges, or the localhost address. The endpoint discriminator can be
+the string \fBnull\fR or of the form \fItype\fR:\fIvalue\fR, where
+type is a decimal number or one of the strings \fBlocal\fR, \fBIP\fR,
+\fBMAC\fR, \fBmagic\fR, or \fBphone\fR. The value is an IP address in
+dotted-decimal notation for the \fBIP\fR type, or a string of bytes in
+hexadecimal, separated by periods or colons for the other types. For
+the MAC type, the value may also be the name of an ethernet or similar
+network interface. This option is currently only available under
+Linux.
+.TP
+.B eap\-interval \fIn
+If this option is given and pppd authenticates the peer with EAP
+(i.e., is the server), pppd will restart EAP authentication every
+\fIn\fR seconds. For EAP SRP\-SHA1, see also the \fBsrp\-interval\fR
+option, which enables lightweight rechallenge.
+.TP
+.B eap\-max\-rreq \fIn
+Set the maximum number of EAP Requests to which pppd will respond (as
+a client) without hearing EAP Success or Failure. (Default is 20.)
+.TP
+.B eap\-max\-sreq \fIn
+Set the maximum number of EAP Requests that pppd will issue (as a
+server) while attempting authentication. (Default is 10.)
+.TP
+.B eap\-restart \fIn
+Set the retransmit timeout for EAP Requests when acting as a server
+(authenticator). (Default is 3 seconds.)
+.TP
+.B eap\-timeout \fIn
+Set the maximum time to wait for the peer to send an EAP Request when
+acting as a client (authenticatee). (Default is 20 seconds.)
+.TP
+.B hide\-password
+When logging the contents of PAP packets, this option causes pppd to
+exclude the password string from the log. This is the default.
+.TP
+.B holdoff \fIn
+Specifies how many seconds to wait before re-initiating the link after
+it terminates. This option only has any effect if the \fIpersist\fR
+or \fIdemand\fR option is used. The holdoff period is not applied if
+the link was terminated because it was idle.
+.TP
+.B idle \fIn
+Specifies that pppd should disconnect if the link is idle for \fIn\fR
+seconds. The link is idle when no data packets (i.e. IP packets) are
+being sent or received. Note: it is not advisable to use this option
+with the \fIpersist\fR option without the \fIdemand\fR option.
+If the \fBactive\-filter\fR
+option is given, data packets which are rejected by the specified
+activity filter also count as the link being idle.
+.TP
+.B ipcp\-accept\-local
+With this option, pppd will accept the peer's idea of our local IP
+address, even if the local IP address was specified in an option.
+.TP
+.B ipcp\-accept\-remote
+With this option, pppd will accept the peer's idea of its (remote) IP
+address, even if the remote IP address was specified in an option.
+.TP
+.B ipcp\-max\-configure \fIn
+Set the maximum number of IPCP configure-request transmissions to
+\fIn\fR (default 10).
+.TP
+.B ipcp\-max\-failure \fIn
+Set the maximum number of IPCP configure-NAKs returned before starting
+to send configure-Rejects instead to \fIn\fR (default 10).
+.TP
+.B ipcp\-max\-terminate \fIn
+Set the maximum number of IPCP terminate-request transmissions to
+\fIn\fR (default 3).
+.TP
+.B ipcp\-restart \fIn
+Set the IPCP restart interval (retransmission timeout) to \fIn\fR
+seconds (default 3).
+.TP
+.B ipparam \fIstring
+Provides an extra parameter to the ip\-up, ip\-pre\-up and ip\-down
+scripts. If this
+option is given, the \fIstring\fR supplied is given as the 6th
+parameter to those scripts.
+.TP
+.B ipv6cp\-accept\-local
+With this option, pppd will accept the peer's idea of our local IPv6
+interface identifier, even if the local IPv6 interface identifier
+was specified in an option.
+.TP
+.B ipv6cp\-max\-configure \fIn
+Set the maximum number of IPv6CP configure-request transmissions to
+\fIn\fR (default 10).
+.TP
+.B ipv6cp\-max\-failure \fIn
+Set the maximum number of IPv6CP configure-NAKs returned before starting
+to send configure-Rejects instead to \fIn\fR (default 10).
+.TP
+.B ipv6cp\-max\-terminate \fIn
+Set the maximum number of IPv6CP terminate-request transmissions to
+\fIn\fR (default 3).
+.TP
+.B ipv6cp\-restart \fIn
+Set the IPv6CP restart interval (retransmission timeout) to \fIn\fR
+seconds (default 3).
+.TP
+.B ipx
+Enable the IPXCP and IPX protocols. This option is presently only
+supported under Linux, and only if your kernel has been configured to
+include IPX support.
+.TP
+.B ipx\-network \fIn
+Set the IPX network number in the IPXCP configure request frame to
+\fIn\fR, a hexadecimal number (without a leading 0x). There is no
+valid default. If this option is not specified, the network number is
+obtained from the peer. If the peer does not have the network number,
+the IPX protocol will not be started.
+.TP
+.B ipx\-node \fIn\fB:\fIm
+Set the IPX node numbers. The two node numbers are separated from each
+other with a colon character. The first number \fIn\fR is the local
+node number. The second number \fIm\fR is the peer's node number. Each
+node number is a hexadecimal number, at most 10 digits long. The node
+numbers on the ipx\-network must be unique. There is no valid
+default. If this option is not specified then the node numbers are
+obtained from the peer.
+.TP
+.B ipx\-router\-name \fI<string>
+Set the name of the router. This is a string and is sent to the peer
+as information data.
+.TP
+.B ipx\-routing \fIn
+Set the routing protocol to be received by this option. More than one
+instance of \fIipx\-routing\fR may be specified. The '\fInone\fR'
+option (0) may be specified as the only instance of ipx\-routing. The
+values may be \fI0\fR for \fINONE\fR, \fI2\fR for \fIRIP/SAP\fR, and
+\fI4\fR for \fINLSP\fR.
+.TP
+.B ipxcp\-accept\-local
+Accept the peer's NAK for the node number specified in the ipx\-node
+option. If a node number was specified, and non-zero, the default is
+to insist that the value be used. If you include this option then you
+will permit the peer to override the entry of the node number.
+.TP
+.B ipxcp\-accept\-network
+Accept the peer's NAK for the network number specified in the
+ipx\-network option. If a network number was specified, and non-zero, the
+default is to insist that the value be used. If you include this
+option then you will permit the peer to override the entry of the node
+number.
+.TP
+.B ipxcp\-accept\-remote
+Use the peer's network number specified in the configure request
+frame. If a node number was specified for the peer and this option was
+not specified, the peer will be forced to use the value which you have
+specified.
+.TP
+.B ipxcp\-max\-configure \fIn
+Set the maximum number of IPXCP configure request frames which the
+system will send to \fIn\fR. The default is 10.
+.TP
+.B ipxcp\-max\-failure \fIn
+Set the maximum number of IPXCP NAK frames which the local system will
+send before it rejects the options. The default value is 3.
+.TP
+.B ipxcp\-max\-terminate \fIn
+Set the maximum number of IPXCP terminate request frames before the
+local system considers that the peer is not listening to them. The
+default value is 3.
+.TP
+.B kdebug \fIn
+Enable debugging code in the kernel-level PPP driver. The argument
+values depend on the specific kernel driver, but in general a value of
+1 will enable general kernel debug messages. (Note that these
+messages are usually only useful for debugging the kernel driver
+itself.) For the Linux 2.2.x kernel driver, the value is a sum of
+bits: 1 to
+enable general debug messages, 2 to request that the contents of
+received packets be printed, and 4 to request that the contents of
+transmitted packets be printed. On most systems, messages printed by
+the kernel are logged by syslog(1) to a file as directed in the
+/etc/syslog.conf configuration file.
+.TP
+.B ktune
+Enables pppd to alter kernel settings as appropriate. Under Linux,
+pppd will enable IP forwarding (i.e. set /proc/sys/net/ipv4/ip_forward
+to 1) if the \fIproxyarp\fR option is used, and will enable the
+dynamic IP address option (i.e. set /proc/sys/net/ipv4/ip_dynaddr to
+1) in demand mode if the local address changes.
+.TP
+.B lcp\-echo\-failure \fIn
+If this option is given, pppd will presume the peer to be dead
+if \fIn\fR LCP echo\-requests are sent without receiving a valid LCP
+echo\-reply. If this happens, pppd will terminate the
+connection. Use of this option requires a non-zero value for the
+\fIlcp\-echo\-interval\fR parameter. This option can be used to enable
+pppd to terminate after the physical connection has been broken
+(e.g., the modem has hung up) in situations where no hardware modem
+control lines are available.
+.TP
+.B lcp\-echo\-interval \fIn
+If this option is given, pppd will send an LCP echo\-request frame to
+the peer every \fIn\fR seconds. Normally the peer should respond to
+the echo\-request by sending an echo\-reply. This option can be used
+with the \fIlcp\-echo\-failure\fR option to detect that the peer is no
+longer connected.
+.TP
+.B lcp\-max\-configure \fIn
+Set the maximum number of LCP configure-request transmissions to
+\fIn\fR (default 10).
+.TP
+.B lcp\-max\-failure \fIn
+Set the maximum number of LCP configure-NAKs returned before starting
+to send configure-Rejects instead to \fIn\fR (default 10).
.TP
-.B +chap
-Require the peer to authenticate itself using CHAP [Cryptographic
-Handshake Authentication Protocol] authentication.
+.B lcp\-max\-terminate \fIn
+Set the maximum number of LCP terminate-request transmissions to
+\fIn\fR (default 3).
.TP
-.B -chap
-Don't agree to authenticate using CHAP.
+.B lcp\-restart \fIn
+Set the LCP restart interval (retransmission timeout) to \fIn\fR
+seconds (default 3).
.TP
-.B -vj
-Disable negotiation of Van Jacobson style IP header compression (use
-default, i.e. no compression).
+.B linkname \fIname\fR
+Sets the logical name of the link to \fIname\fR. Pppd will create a
+file named \fBppp\-\fIname\fB.pid\fR in /var/run (or /etc/ppp on some
+systems) containing its process ID. This can be useful in determining
+which instance of pppd is responsible for the link to a given peer
+system. This is a privileged option.
.TP
-.B debug
-Increase debugging level (same as
-.B -d
-).
+.B local
+Don't use the modem control lines. With this option, pppd will ignore
+the state of the CD (Carrier Detect) signal from the modem and will
+not change the state of the DTR (Data Terminal Ready) signal. This is
+the opposite of the \fBmodem\fR option.
+.TP
+.B logfd \fIn
+Send log messages to file descriptor \fIn\fR. Pppd will send log
+messages to at most one file or file descriptor (as well as sending
+the log messages to syslog), so this option and the \fBlogfile\fR
+option are mutually exclusive. The default is for pppd to send log
+messages to stdout (file descriptor 1), unless the serial port is
+already open on stdout.
+.TP
+.B logfile \fIfilename
+Append log messages to the file \fIfilename\fR (as well as sending the
+log messages to syslog). The file is opened with the privileges of
+the user who invoked pppd, in append mode.
.TP
-.B domain \fI<d>
-Append the domain name <d> to the local host name for authentication
-purposes. For example, if gethostname() returns the name porsche, but the
-fully qualified domain name is porsche.Quotron.COM, you would use the
-domain option to set the domain name to Quotron.COM.
+.B login
+Use the system password database for authenticating the peer using
+PAP, and record the user in the system wtmp file. Note that the peer
+must have an entry in the /etc/ppp/pap\-secrets file as well as the
+system password database to be allowed access. See also the
+\fBenable\-session\fR option.
+.TP
+.B master_detach
+If multilink is enabled and this pppd process is the multilink bundle
+master, and the link controlled by this pppd process terminates, this
+pppd process continues to run in order to maintain the bundle. If the
+\fBmaster_detach\fR option has been given, pppd will detach from its
+controlling terminal in this situation, even if the \fBnodetach\fR
+option has been given.
+.TP
+.B maxconnect \fIn
+Terminate the connection when it has been available for network
+traffic for \fIn\fR seconds (i.e. \fIn\fR seconds after the first
+network control protocol comes up).
+.TP
+.B maxfail \fIn
+Terminate after \fIn\fR consecutive failed connection attempts. A
+value of 0 means no limit. The default value is 10.
.TP
.B modem
-Use the modem control lines. (This option is not fully implemented.)
-.TP
-.B local
-Don't use the modem control lines.
+Use the modem control lines. This option is the default. With this
+option, pppd will wait for the CD (Carrier Detect) signal from the
+modem to be asserted when opening the serial device (unless a connect
+script is specified), and it will drop the DTR (Data Terminal Ready)
+signal briefly when the connection is terminated and before executing
+the connect script. On Ultrix, this option implies hardware flow
+control, as for the \fIcrtscts\fR option. This is the opposite of the
+\fBlocal\fR option.
+.TP
+.B mp
+Enables the use of PPP multilink; this is an alias for the `multilink'
+option. This option is currently only available under Linux.
+.TP
+.B mppe\-stateful
+Allow MPPE to use stateful mode. Stateless mode is still attempted first.
+The default is to disallow stateful mode.
+.TP
+.B mpshortseq
+Enables the use of short (12-bit) sequence numbers in multilink
+headers, as opposed to 24-bit sequence numbers. This option is only
+available under Linux, and only has any effect if multilink is
+enabled (see the multilink option).
+.TP
+.B mrru \fIn
+Sets the Maximum Reconstructed Receive Unit to \fIn\fR. The MRRU is
+the maximum size for a received packet on a multilink bundle, and is
+analogous to the MRU for the individual links. This option is
+currently only available under Linux, and only has any effect if
+multilink is enabled (see the multilink option).
+.TP
+.B ms\-dns \fI<addr>
+If pppd is acting as a server for Microsoft Windows clients, this
+option allows pppd to supply one or two DNS (Domain Name Server)
+addresses to the clients. The first instance of this option specifies
+the primary DNS address; the second instance (if given) specifies the
+secondary DNS address. (This option was present in some older
+versions of pppd under the name \fBdns\-addr\fR.)
+.TP
+.B ms\-wins \fI<addr>
+If pppd is acting as a server for Microsoft Windows or "Samba"
+clients, this option allows pppd to supply one or two WINS (Windows
+Internet Name Services) server addresses to the clients. The first
+instance of this option specifies the primary WINS address; the second
+instance (if given) specifies the secondary WINS address.
+.TP
+.B multilink
+Enables the use of the PPP multilink protocol. If the peer also
+supports multilink, then this link can become part of a bundle between
+the local system and the peer. If there is an existing bundle to the
+peer, pppd will join this link to that bundle, otherwise pppd will
+create a new bundle. See the MULTILINK section below. This option is
+currently only available under Linux.
+.TP
+.B name \fIname
+Set the name of the local system for authentication purposes to
+\fIname\fR. This is a privileged option. With this option, pppd will
+use lines in the secrets files which have \fIname\fR as the second
+field when looking for a secret to use in authenticating the peer. In
+addition, unless overridden with the \fIuser\fR option, \fIname\fR
+will be used as the name to send to the peer when authenticating the
+local system to the peer. (Note that pppd does not append the domain
+name to \fIname\fR.)
+.TP
+.B noaccomp
+Disable Address/Control compression in both directions (send and
+receive).
+.TP
+.B noauth
+Do not require the peer to authenticate itself. This option is
+privileged.
+.TP
+.B nobsdcomp
+Disables BSD-Compress compression; \fBpppd\fR will not request or
+agree to compress packets using the BSD-Compress scheme.
+.TP
+.B noccp
+Disable CCP (Compression Control Protocol) negotiation. This option
+should only be required if the peer is buggy and gets confused by
+requests from pppd for CCP negotiation.
+.TP
+.B nocrtscts
+Disable hardware flow control (i.e. RTS/CTS) on the serial port.
+If neither the \fIcrtscts\fR nor the \fInocrtscts\fR nor the
+\fIcdtrcts\fR nor the \fInocdtrcts\fR option is given, the hardware
+flow control setting for the serial port is left unchanged.
+.TP
+.B nocdtrcts
+This option is a synonym for \fInocrtscts\fR. Either of these options will
+disable both forms of hardware flow control.
+.TP
+.B nodefaultroute
+Disable the \fIdefaultroute\fR option. The system administrator who
+wishes to prevent users from creating default routes with pppd
+can do so by placing this option in the /etc/ppp/options file.
+.TP
+.B nodeflate
+Disables Deflate compression; pppd will not request or agree to
+compress packets using the Deflate scheme.
+.TP
+.B nodetach
+Don't detach from the controlling terminal. Without this option, if a
+serial device other than the terminal on the standard input is
+specified, pppd will fork to become a background process.
+.TP
+.B noendpoint
+Disables pppd from sending an endpoint discriminator to the peer or
+accepting one from the peer (see the MULTILINK section below). This
+option should only be required if the peer is buggy.
+.TP
+.B noip
+Disable IPCP negotiation and IP communication. This option should
+only be required if the peer is buggy and gets confused by requests
+from pppd for IPCP negotiation.
+.TP
+.B noipv6
+Disable IPv6CP negotiation and IPv6 communication. This option should
+only be required if the peer is buggy and gets confused by requests
+from pppd for IPv6CP negotiation.
+.TP
+.B noipdefault
+Disables the default behaviour when no local IP address is specified,
+which is to determine (if possible) the local IP address from the
+hostname. With this option, the peer will have to supply the local IP
+address during IPCP negotiation (unless it specified explicitly on the
+command line or in an options file).
+.TP
+.B noipx
+Disable the IPXCP and IPX protocols. This option should only be
+required if the peer is buggy and gets confused by requests from pppd
+for IPXCP negotiation.
+.TP
+.B noktune
+Opposite of the \fIktune\fR option; disables pppd from changing system
+settings.
+.TP
+.B nolock
+Opposite of the \fIlock\fR option; specifies that pppd should not
+create a UUCP-style lock file for the serial device. This option is
+privileged.
+.TP
+.B nolog
+Do not send log messages to a file or file descriptor. This option
+cancels the \fBlogfd\fR and \fBlogfile\fR options.
+.TP
+.B nomagic
+Disable magic number negotiation. With this option, pppd cannot
+detect a looped-back line. This option should only be needed if the
+peer is buggy.
+.TP
+.B nomp
+Disables the use of PPP multilink. This option is currently only
+available under Linux.
+.TP
+.B nomppe
+Disables MPPE (Microsoft Point to Point Encryption). This is the default.
+.TP
+.B nomppe\-40
+Disable 40-bit encryption with MPPE.
+.TP
+.B nomppe\-128
+Disable 128-bit encryption with MPPE.
+.TP
+.B nomppe\-stateful
+Disable MPPE stateful mode. This is the default.
+.TP
+.B nompshortseq
+Disables the use of short (12-bit) sequence numbers in the PPP
+multilink protocol, forcing the use of 24-bit sequence numbers. This
+option is currently only available under Linux, and only has any
+effect if multilink is enabled.
+.TP
+.B nomultilink
+Disables the use of PPP multilink. This option is currently only
+available under Linux.
+.TP
+.B nopcomp
+Disable protocol field compression negotiation in both the receive and
+the transmit direction.
+.TP
+.B nopersist
+Exit once a connection has been made and terminated. This is the
+default unless the \fIpersist\fR or \fIdemand\fR option has been
+specified.
+.TP
+.B nopredictor1
+Do not accept or agree to Predictor\-1 compression.
+.TP
+.B noproxyarp
+Disable the \fIproxyarp\fR option. The system administrator who
+wishes to prevent users from creating proxy ARP entries with pppd can
+do so by placing this option in the /etc/ppp/options file.
+.TP
+.B noremoteip
+Allow pppd to operate without having an IP address for the peer. This
+option is only available under Linux. Normally, pppd will request the
+peer's IP address, and if the peer does not supply it, pppd will use
+an arbitrary address in the 10.x.x.x subnet.
+With this option, if the peer does
+not supply its IP address, pppd will not ask the peer for it, and will
+not set the destination address of the ppp interface. In this
+situation, the ppp interface can be used for routing by creating
+device routes, but the peer itself cannot be addressed directly for IP
+traffic.
+.TP
+.B notty
+Normally, pppd requires a terminal device. With this option, pppd
+will allocate itself a pseudo-tty master/slave pair and use the slave
+as its terminal device. Pppd will create a child process to act as a
+`character shunt' to transfer characters between the pseudo-tty master
+and its standard input and output. Thus pppd will transmit characters
+on its standard output and receive characters on its standard input
+even if they are not terminal devices. This option increases the
+latency and CPU overhead of transferring data over the ppp interface
+as all of the characters sent and received must flow through the
+character shunt process. An explicit device name may not be given if
+this option is used.
+.TP
+.B novj
+Disable Van Jacobson style TCP/IP header compression in both the
+transmit and the receive direction.
+.TP
+.B novjccomp
+Disable the connection-ID compression option in Van Jacobson style
+TCP/IP header compression. With this option, pppd will not omit the
+connection-ID byte from Van Jacobson compressed TCP/IP headers, nor
+ask the peer to do so.
+.TP
+.B papcrypt
+Indicates that all secrets in the /etc/ppp/pap\-secrets file which are
+used for checking the identity of the peer are encrypted, and thus
+pppd should not accept a password which, before encryption, is
+identical to the secret from the /etc/ppp/pap\-secrets file.
+.TP
+.B pap\-max\-authreq \fIn
+Set the maximum number of PAP authenticate-request transmissions to
+\fIn\fR (default 10).
+.TP
+.B pap\-restart \fIn
+Set the PAP restart interval (retransmission timeout) to \fIn\fR
+seconds (default 3).
+.TP
+.B pap\-timeout \fIn
+Set the maximum time that pppd will wait for the peer to authenticate
+itself with PAP to \fIn\fR seconds (0 means no limit).
+.TP
+.B pass\-filter \fIfilter\-expression
+Specifies a packet filter to applied to data packets being sent or
+received to determine which packets should be allowed to pass.
+Packets which are rejected by the filter are silently discarded. This
+option can be used to prevent specific network daemons (such as
+routed) using up link bandwidth, or to provide a very basic firewall
+capability.
+The \fIfilter\-expression\fR syntax is as described for tcpdump(1),
+except that qualifiers which are inappropriate for a PPP link, such as
+\fBether\fR and \fBarp\fR, are not permitted. Generally the filter
+expression should be enclosed in single-quotes to prevent whitespace
+in the expression from being interpreted by the shell. Note that it
+is possible to apply different constraints to incoming and outgoing
+packets using the \fBinbound\fR and \fBoutbound\fR qualifiers. This
+option is currently only available under Linux, and requires that the
+kernel was configured to include PPP filtering support (CONFIG_PPP_FILTER).
+.TP
+.B password \fIpassword\-string
+Specifies the password to use for authenticating to the peer. Use
+of this option is discouraged, as the password is likely to be visible
+to other users on the system (for example, by using ps(1)).
+.TP
+.B persist
+Do not exit after a connection is terminated; instead try to reopen
+the connection. The \fBmaxfail\fR option still has an effect on
+persistent connections.
+.TP
+.B plugin \fIfilename
+Load the shared library object file \fIfilename\fR as a plugin. This
+is a privileged option. If \fIfilename\fR does not contain a slash
+(/), pppd will look in the \fB/usr/lib/pppd/\fIversion\fR directory
+for the plugin, where
+\fIversion\fR is the version number of pppd (for example, 2.4.2).
+.TP
+.B predictor1
+Request that the peer compress frames that it sends using Predictor-1
+compression, and agree to compress transmitted frames with Predictor-1
+if requested. This option has no effect unless the kernel driver
+supports Predictor-1 compression.
+.TP
+.B privgroup \fIgroup\-name
+Allows members of group \fIgroup\-name\fR to use privileged options.
+This is a privileged option. Use of this option requires care as
+there is no guarantee that members of \fIgroup\-name\fR cannot use pppd
+to become root themselves. Consider it equivalent to putting the
+members of \fIgroup\-name\fR in the kmem or disk group.
.TP
-.B name \fI<n>
-Set the name of the local system for authentication purposes to <n>.
+.B proxyarp
+Add an entry to this system's ARP [Address Resolution Protocol] table
+with the IP address of the peer and the Ethernet address of this
+system. This will have the effect of making the peer appear to other
+systems to be on the local ethernet.
+.TP
+.B pty \fIscript
+Specifies that the command \fIscript\fR is to be used to communicate
+rather than a specific terminal device. Pppd will allocate itself a
+pseudo-tty master/slave pair and use the slave as its terminal
+device. The \fIscript\fR will be run in a child process with the
+pseudo-tty master as its standard input and output. An explicit
+device name may not be given if this option is used. (Note: if the
+\fIrecord\fR option is used in conjunction with the \fIpty\fR option,
+the child process will have pipes on its standard input and output.)
+.TP
+.B receive\-all
+With this option, pppd will accept all control characters from the
+peer, including those marked in the receive asyncmap. Without this
+option, pppd will discard those characters as specified in RFC1662.
+This option should only be needed if the peer is buggy.
+.TP
+.B record \fIfilename
+Specifies that pppd should record all characters sent and received to
+a file named \fIfilename\fR. This file is opened in append mode,
+using the user's user-ID and permissions. This option is implemented
+using a pseudo-tty and a process to transfer characters between the
+pseudo-tty and the real serial device, so it will increase the latency
+and CPU overhead of transferring data over the ppp interface. The
+characters are stored in a tagged format with timestamps, which can be
+displayed in readable form using the pppdump(8) program.
+.TP
+.B remotename \fIname
+Set the assumed name of the remote system for authentication purposes
+to \fIname\fR.
.TP
-.B user \fI<u>
-Set the user name to use for authenticating this machine with the peer
-using PAP to <u>.
+.B remotenumber \fInumber
+Set the assumed telephone number of the remote system for authentication
+purposes to \fInumber\fR.
.TP
-.B usehostname
-Enforce the use of the hostname as the name of the local system for
-authentication purposes (overrides the
-.B name
-option).
+.B refuse\-chap
+With this option, pppd will not agree to authenticate itself to the
+peer using CHAP.
.TP
-.B remotename \fI<n>
-Set the assumed name of the remote system for authentication purposes
-to <n>.
+.B refuse\-mschap
+With this option, pppd will not agree to authenticate itself to the
+peer using MS\-CHAP.
.TP
-.B proxyarp
-Add an entry to this system's ARP [Address Resolution Protocol] table
-with the IP address of the peer and the Ethernet address of this
-system.
+.B refuse\-mschap\-v2
+With this option, pppd will not agree to authenticate itself to the
+peer using MS\-CHAPv2.
.TP
-.B login
-Use the system password database for authenticating the peer using
-PAP.
+.B refuse\-eap
+With this option, pppd will not agree to authenticate itself to the
+peer using EAP.
.TP
-.B lcp-restart \fI<n>
-Set the LCP restart interval (retransmission timeout) to <n> seconds
-(default 3).
+.B refuse\-pap
+With this option, pppd will not agree to authenticate itself to the
+peer using PAP.
.TP
-.B lcp-max-terminate \fI<n>
-Set the maximum number of LCP terminate-request transmissions to <n>
-(default 3).
+.B require\-chap
+Require the peer to authenticate itself using CHAP [Challenge
+Handshake Authentication Protocol] authentication.
.TP
-.B lcp-max-configure \fI<n>
-Set the maximum number of LCP configure-request transmissions to <n>
-(default 10).
+.B require\-mppe
+Require the use of MPPE (Microsoft Point to Point Encryption). This
+option disables all other compression types. This option enables
+both 40-bit and 128-bit encryption. In order for MPPE to successfully
+come up, you must have authenticated with either MS\-CHAP or MS\-CHAPv2.
+This option is presently only supported under Linux, and only if your
+kernel has been configured to include MPPE support.
.TP
-.B lcp-max-failure \fI<n>
-Set the maximum number of LCP configure-NAKs returned before starting
-to send configure-Rejects instead to <n> (default 10).
+.B require\-mppe\-40
+Require the use of MPPE, with 40-bit encryption.
.TP
-.B ipcp-restart \fI<n>
-Set the IPCP restart interval (retransmission timeout) to <n> seconds
-(default 3).
+.B require\-mppe\-128
+Require the use of MPPE, with 128-bit encryption.
.TP
-.B ipcp-max-terminate \fI<n>
-Set the maximum number of IPCP terminate-request transmissions to <n>
-(default 3).
+.B require\-mschap
+Require the peer to authenticate itself using MS\-CHAP [Microsoft Challenge
+Handshake Authentication Protocol] authentication.
.TP
-.B ipcp-max-configure \fI<n>
-Set the maximum number of IPCP configure-request transmissions to <n>
-(default 10).
+.B require\-mschap\-v2
+Require the peer to authenticate itself using MS\-CHAPv2 [Microsoft Challenge
+Handshake Authentication Protocol, Version 2] authentication.
.TP
-.B ipcp-max-failure \fI<n>
-Set the maximum number of IPCP configure-NAKs returned before starting
-to send configure-Rejects instead to <n> (default 10).
+.B require\-eap
+Require the peer to authenticate itself using EAP [Extensible
+Authentication Protocol] authentication.
.TP
-.B pap-restart \fI<n>
-Set the PAP restart interval (retransmission timeout) to <n> seconds
-(default 3).
+.B require\-pap
+Require the peer to authenticate itself using PAP [Password
+Authentication Protocol] authentication.
.TP
-.B pap-max-authreq \fI<n>
-Set the maximum number of PAP authenticate-request transmissions to
-<n> (default 10).
+.B set \fIname\fR=\fIvalue
+Set an environment variable for scripts that are invoked by pppd.
+When set by a privileged source, the variable specified by \fIname\fR
+cannot be changed by options contained in an unprivileged source. See
+also the \fIunset\fR option and the environment described in
+\fISCRIPTS\fR.
.TP
-.B chap-restart \fI<n>
-Set the CHAP restart interval (retransmission timeout for challenges)
-to <n> seconds (default 3).
+.B show\-password
+When logging the contents of PAP packets, this option causes pppd to
+show the password string in the log message.
.TP
-.B chap-max-challenge \fI<n>
-Set the maximum number of CHAP challenge transmissions to <n> (default
-10).
+.B silent
+With this option, pppd will not transmit LCP packets to initiate a
+connection until a valid LCP packet is received from the peer (as for
+the `passive' option with ancient versions of pppd).
+.TP
+.B srp\-interval \fIn
+If this parameter is given and pppd uses EAP SRP\-SHA1 to authenticate
+the peer (i.e., is the server), then pppd will use the optional
+lightweight SRP rechallenge mechanism at intervals of \fIn\fR
+seconds. This option is faster than \fBeap\-interval\fR
+reauthentication because it uses a hash\-based mechanism and does not
+derive a new session key.
+.TP
+.B srp\-pn\-secret \fIstring
+Set the long-term pseudonym-generating secret for the server. This
+value is optional and if set, needs to be known at the server
+(authenticator) side only, and should be different for each server (or
+poll of identical servers). It is used along with the current date to
+generate a key to encrypt and decrypt the client's identity contained
+in the pseudonym.
+.TP
+.B srp\-use\-pseudonym
+When operating as an EAP SRP\-SHA1 client, attempt to use the pseudonym
+stored in ~/.ppp_pseudonym first as the identity, and save in this
+file any pseudonym offered by the peer during authentication.
+.TP
+.B sync
+Use synchronous HDLC serial encoding instead of asynchronous.
+The device used by pppd with this option must have sync support.
+Currently supports Microgate SyncLink adapters
+under Linux and FreeBSD 2.2.8 and later.
+.TP
+.B unit \fInum
+Sets the ppp unit number (for a ppp0 or ppp1 etc interface name) for outbound
+connections.
+.TP
+.B unset \fIname
+Remove a variable from the environment variable for scripts that are
+invoked by pppd. When specified by a privileged source, the variable
+\fIname\fR cannot be set by options contained in an unprivileged
+source. See also the \fIset\fR option and the environment described
+in \fISCRIPTS\fR.
+.TP
+.B updetach
+With this option, pppd will detach from its controlling terminal once
+it has successfully established the ppp connection (to the point where
+the first network control protocol, usually the IP control protocol,
+has come up).
.TP
-.B chap-interval \fI<n>
-If this option is given,
-.I pppd
-will rechallenge the peer every <n> seconds.
+.B usehostname
+Enforce the use of the hostname (with domain name appended, if given)
+as the name of the local system for authentication purposes (overrides
+the \fIname\fR option). This option is not normally needed since the
+\fIname\fR option is privileged.
+.TP
+.B usepeerdns
+Ask the peer for up to 2 DNS server addresses. The addresses supplied
+by the peer (if any) are passed to the /etc/ppp/ip\-up script in the
+environment variables DNS1 and DNS2, and the environment variable
+USEPEERDNS will be set to 1. In addition, pppd will create an
+/etc/ppp/resolv.conf file containing one or two nameserver lines with
+the address(es) supplied by the peer.
+.TP
+.B user \fIname
+Sets the name used for authenticating the local system to the peer to
+\fIname\fR.
+.TP
+.B vj\-max\-slots \fIn
+Sets the number of connection slots to be used by the Van Jacobson
+TCP/IP header compression and decompression code to \fIn\fR, which
+must be between 2 and 16 (inclusive).
+.TP
+.B welcome \fIscript
+Run the executable or shell command specified by \fIscript\fR before
+initiating PPP negotiation, after the connect script (if any) has
+completed. A value for this option from a privileged source cannot be
+overridden by a non-privileged user.
+.TP
+.B xonxoff
+Use software flow control (i.e. XON/XOFF) to control the flow of data on
+the serial port.
.SH OPTIONS FILES
-Options can be taken from files as well as the command line.
-.I pppd
-reads options from the files /etc/ppp/options and $HOME/.ppprc before
-looking at the command line. An options file is parsed into a series
-of words, delimited by whitespace. Whitespace can be included in a
-word by enclosing the word in quotes ("). A backslash (\\) quotes the
-following character. A hash (#) starts a comment, which continues
-until the end of the line.
-.SH AUTHENTICATION
+Options can be taken from files as well as the command line. Pppd
+reads options from the files /etc/ppp/options, ~/.ppprc and
+/etc/ppp/options.\fIttyname\fR (in that order) before processing the
+options on the command line. (In fact, the command-line options are
+scanned to find the terminal name before the options.\fIttyname\fR
+file is read.) In forming the name of the options.\fIttyname\fR file,
+the initial /dev/ is removed from the terminal name, and any remaining
+/ characters are replaced with dots.
+.PP
+An options file is parsed into a series of words, delimited by
+whitespace. Whitespace can be included in a word by enclosing the
+word in double-quotes ("). A backslash (\\) quotes the following character.
+A hash (#) starts a comment, which continues until the end of the
+line. There is no restriction on using the \fIfile\fR or \fIcall\fR
+options within an options file.
+.SH SECURITY
.I pppd
provides system administrators with sufficient access control that PPP
access to a server machine can be provided to legitimate users without
fear of compromising the security of the server or the network it's
-on. In part this is provided by the /etc/ppp/options file, where the
-administrator can place options to require authentication whenever
-.I pppd
-is run, and in part by the PAP and CHAP secrets files, where the
-administrator can restrict the set of IP addresses which individual
-users may use.
+on. This control is provided through restrictions on which IP
+addresses the peer may use, based on its authenticated identity (if
+any), and through restrictions on which options a non-privileged user
+may use. Several of pppd's options are privileged, in particular
+those which permit potentially insecure configurations; these options
+are only accepted in files which are under the control of the system
+administrator, or if pppd is being run by root.
+.PP
+The default behaviour of pppd is to allow an unauthenticated peer to
+use a given IP address only if the system does not already have a
+route to that IP address. For example, a system with a
+permanent connection to the wider internet will normally have a
+default route, and thus all peers will have to authenticate themselves
+in order to set up a connection. On such a system, the \fIauth\fR
+option is the default. On the other hand, a system where the
+PPP link is the only connection to the internet will not normally have
+a default route, so the peer will be able to use almost any IP address
+without authenticating itself.
+.PP
+As indicated above, some security-sensitive options are privileged,
+which means that they may not be used by an ordinary non-privileged
+user running a setuid-root pppd, either on the command line, in the
+user's ~/.ppprc file, or in an options file read using the \fIfile\fR
+option. Privileged options may be used in /etc/ppp/options file or in
+an options file read using the \fIcall\fR option. If pppd is being
+run by the root user, privileged options can be used without
+restriction.
+.PP
+When opening the device, pppd uses either the invoking user's user ID
+or the root UID (that is, 0), depending on whether the device name was
+specified by the user or the system administrator. If the device name
+comes from a privileged source, that is, /etc/ppp/options or an
+options file read using the \fIcall\fR option, pppd uses full root
+privileges when opening the device. Thus, by creating an appropriate
+file under /etc/ppp/peers, the system administrator can allow users to
+establish a ppp connection via a device which they would not normally
+have permission to access. Otherwise pppd uses the invoking user's
+real UID when opening the device.
+.SH AUTHENTICATION
+Authentication is the process whereby one peer convinces the other of
+its identity. This involves the first peer sending its name to the
+other, together with some kind of secret information which could only
+come from the genuine authorized user of that name. In such an
+exchange, we will call the first peer the "client" and the other the
+"server". The client has a name by which it identifies itself to the
+server, and the server also has a name by which it identifies itself
+to the client. Generally the genuine client shares some secret (or
+password) with the server, and authenticates itself by proving that it
+knows that secret. Very often, the names used for authentication
+correspond to the internet hostnames of the peers, but this is not
+essential.
.LP
-The default behaviour of
-.I pppd
-is to agree to authenticate if requested, and to not
-require authentication from the peer. However,
-.I pppd
-will not agree to
-authenticate itself with a particular protocol if it has no secrets
-which could be used to do so.
-.LP
-Authentication is based on secrets, which are selected from secrets
-files (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP).
-Both secrets files have the same format, and both can store secrets
-for several combinations of server (authenticating peer) and client
-(peer being authenticated). Note that
-.I pppd
-can be both a server
-and client, and that different protocols can be used in the two
-directions if desired.
-.LP
-A secrets file is parsed into words as for a options file. A secret
-is specified by a line containing at least 3 words, in the order
-client, server, secret. Any following words on the same line are
-taken to be a list of acceptable IP addresses for that client. If
-there are only 3 words on the line, it is assumed that any IP address
-is OK; to disallow all IP addresses, use "-". If the secret starts
-with an `@', what follows is assumed to be the name of a file from
-which to read the secret. A "*" as the client or server name matches
-any name. When selecting a secret, \fIpppd\fR takes the best match, i.e.
-the match with the fewest wildcards.
+At present, pppd supports three authentication protocols: the Password
+Authentication Protocol (PAP), Challenge Handshake Authentication
+Protocol (CHAP), and Extensible Authentication Protocol (EAP). PAP
+involves the client sending its name and a cleartext password to the
+server to authenticate itself. In contrast, the server initiates the
+CHAP authentication exchange by sending a challenge to the client (the
+challenge packet includes the server's name). The client must respond
+with a response which includes its name plus a hash value derived from
+the shared secret and the challenge, in order to prove that it knows
+the secret. EAP supports CHAP-style authentication, and also includes
+the SRP\-SHA1 mechanism, which is resistant to dictionary-based attacks
+and does not require a cleartext password on the server side.
+.LP
+The PPP protocol, being symmetrical, allows both peers to require the
+other to authenticate itself. In that case, two separate and
+independent authentication exchanges will occur. The two exchanges
+could use different authentication protocols, and in principle,
+different names could be used in the two exchanges.
+.LP
+The default behaviour of pppd is to agree to authenticate if
+requested, and to not require authentication from the peer. However,
+pppd will not agree to authenticate itself with a particular protocol
+if it has no secrets which could be used to do so.
+.LP
+Pppd stores secrets for use in authentication in secrets
+files (/etc/ppp/pap\-secrets for PAP, /etc/ppp/chap\-secrets for CHAP,
+MS\-CHAP, MS\-CHAPv2, and EAP MD5-Challenge, and /etc/ppp/srp\-secrets
+for EAP SRP\-SHA1).
+All secrets files have the same format. The secrets files can
+contain secrets for pppd to use in authenticating itself to other
+systems, as well as secrets for pppd to use when authenticating other
+systems to itself.
+.LP
+Each line in a secrets file contains one secret. A given secret is
+specific to a particular combination of client and server - it can
+only be used by that client to authenticate itself to that server.
+Thus each line in a secrets file has at least 3 fields: the name of
+the client, the name of the server, and the secret. These fields may
+be followed by a list of the IP addresses that the specified client
+may use when connecting to the specified server.
+.LP
+A secrets file is parsed into words as for a options file, so the
+client name, server name and secrets fields must each be one word,
+with any embedded spaces or other special characters quoted or
+escaped. Note that case is significant in the client and server names
+and in the secret.
+.LP
+If the secret starts with an `@', what follows is assumed to be the
+name of a file from which to read the secret. A "*" as the client or
+server name matches any name. When selecting a secret, pppd takes the
+best match, i.e. the match with the fewest wildcards.
+.LP
+Any following words on the same line are taken to be a list of
+acceptable IP addresses for that client. If there are only 3 words on
+the line, or if the first word is "\-", then all IP addresses are
+disallowed. To allow any address, use "*". A word starting with "!"
+indicates that the specified address is \fInot\fR acceptable. An
+address may be followed by "/" and a number \fIn\fR, to indicate a
+whole subnet, i.e. all addresses which have the same value in the most
+significant \fIn\fR bits. In this form, the address may be followed
+by a plus sign ("+") to indicate that one address from the subnet is
+authorized, based on the ppp network interface unit number in use.
+In this case, the host part of the address will be set to the unit
+number plus one.
.LP
Thus a secrets file contains both secrets for use in authenticating
other hosts, plus secrets which we use for authenticating ourselves to
-others. Which secret to use is chosen based on the names of the host
-(the `local name') and its peer (the `remote name'). The local name
-is set as follows:
-.TP 3
-if the \fBusehostname\fR option is given,
-then the local name is the hostname of this machine
-(with the domain appended, if given)
-.TP 3
-else if the \fBname\fR option is given,
-then use the argument of the first \fBname\fR option seen
-.TP 3
-else if the local IP address is specified with a hostname,
-then use that name
-.TP 3
-else use the hostname of this machine (with the domain appended, if given)
-.LP
-When authenticating ourselves using PAP, there is also a `username'
-which is the local name by default, but can be set with the \fBuser\fR
-option or the \fB+ua\fR option.
-.LP
-The remote name is set as follows:
-.TP 3
-if the \fBremotename\fR option is given,
-then use the argument of the last \fBremotename\fR option seen
-.TP 3
-else if the remote IP address is specified with a hostname,
-then use that host name
-.TP 3
-else the remote name is the null string "".
-.LP
-Secrets are selected from the PAP secrets file as follows:
-.TP 2
-*
-For authenticating the peer, look for a secret with client ==
-username specified in the PAP authenticate-request, and server ==
-local name.
-.TP 2
-*
-For authenticating ourselves to the peer, look for a secret with
-client == our username, server == remote name.
-.LP
-When authenticating the peer with PAP, a secret of "" matches any
-password supplied by the peer. If the password doesn't match the
-secret, the password is encrypted using crypt() and checked against
-the secret again; thus secrets for authenticating the peer can be
-stored in encrypted form. If the \fBlogin\fR option was specified, the
-username and password are also checked against the system password
-database. Thus, the system administrator can set up the pap-secrets
-file to allow PPP access only to certain users, and to restrict the
-set of IP addresses that each user can use.
-.LP
-Secrets are selected from the CHAP secrets file as follows:
-.TP 2
-*
-For authenticating the peer, look for a secret with client == name
-specified in the CHAP-Response message, and server == local name.
-.TP 2
-*
-For authenticating ourselves to the peer, look for a secret with
-client == local name, and server == name specified in the
-CHAP-Challenge message.
+others. When pppd is authenticating the peer (checking the peer's
+identity), it chooses a secret with the peer's name in the first
+field and the name of the local system in the second field. The
+name of the local system defaults to the hostname, with the domain
+name appended if the \fIdomain\fR option is used. This default can be
+overridden with the \fIname\fR option, except when the
+\fIusehostname\fR option is used. (For EAP SRP\-SHA1, see the
+srp\-entry(8) utility for generating proper validator entries to be
+used in the "secret" field.)
+.LP
+When pppd is choosing a secret to use in authenticating itself to the
+peer, it first determines what name it is going to use to identify
+itself to the peer. This name can be specified by the user with the
+\fIuser\fR option. If this option is not used, the name defaults to
+the name of the local system, determined as described in the previous
+paragraph. Then pppd looks for a secret with this name in the first
+field and the peer's name in the second field. Pppd will know the
+name of the peer if CHAP or EAP authentication is being used, because
+the peer will have sent it in the challenge packet. However, if PAP
+is being used, pppd will have to determine the peer's name from the
+options specified by the user. The user can specify the peer's name
+directly with the \fIremotename\fR option. Otherwise, if the remote
+IP address was specified by a name (rather than in numeric form), that
+name will be used as the peer's name. Failing that, pppd will use the
+null string as the peer's name.
+.LP
+When authenticating the peer with PAP, the supplied password is first
+compared with the secret from the secrets file. If the password
+doesn't match the secret, the password is encrypted using crypt() and
+checked against the secret again. Thus secrets for authenticating the
+peer can be stored in encrypted form if desired. If the
+\fIpapcrypt\fR option is given, the first (unencrypted) comparison is
+omitted, for better security.
+.LP
+Furthermore, if the \fIlogin\fR option was specified, the username and
+password are also checked against the system password database. Thus,
+the system administrator can set up the pap\-secrets file to allow PPP
+access only to certain users, and to restrict the set of IP addresses
+that each user can use. Typically, when using the \fIlogin\fR option,
+the secret in /etc/ppp/pap\-secrets would be "", which will match any
+password supplied by the peer. This avoids the need to have the same
+secret in two places.
.LP
Authentication must be satisfactorily completed before IPCP (or any
-other Network Control Protocol) can be started. If authentication
-fails, \fIpppd\fR will terminated the link (by closing LCP). If IPCP
-negotiates an unacceptable IP address for the remote host, IPCP will
-be closed. IP packets can only be sent or received when IPCP is open.
+other Network Control Protocol) can be started. If the peer is
+required to authenticate itself, and fails to do so, pppd will
+terminated the link (by closing LCP). If IPCP negotiates an
+unacceptable IP address for the remote host, IPCP will be closed. IP
+packets can only be sent or received when IPCP is open.
+.LP
+In some cases it is desirable to allow some hosts which can't
+authenticate themselves to connect and use one of a restricted set of
+IP addresses, even when the local host generally requires
+authentication. If the peer refuses to authenticate itself when
+requested, pppd takes that as equivalent to authenticating with PAP
+using the empty string for the username and password. Thus, by adding
+a line to the pap\-secrets file which specifies the empty string for
+the client and password, it is possible to allow restricted access to
+hosts which refuse to authenticate themselves.
.SH ROUTING
.LP
-When IPCP negotiation is completed successfully,
-.I pppd
-will inform the kernel of the local and remote IP addresses for the
-ppp interface. This is sufficient to create a
-host route to the remote end of the link, which will enable the peers
-to exchange IP packets. Communication with other machines generally
-requires further modification to routing tables and/or ARP (Address
-Resolution Protocol) tables. In some cases this will be done
-automatically through the actions of the \fIrouted\fR or \fIgated\fR
-daemons, but in most cases some further intervention is required.
-.LP
-Sometimes it is desirable
-to add a default route through the remote host, as in the case of a
-machine whose only connection to the Internet is through the ppp
-interface. The \fBdefaultroute\fR option causes \fIpppd\fR to create such a
-default route when IPCP comes up, and delete it when the link is
-terminated.
+When IPCP negotiation is completed successfully, pppd will inform the
+kernel of the local and remote IP addresses for the ppp interface.
+This is sufficient to create a host route to the remote end of the
+link, which will enable the peers to exchange IP packets.
+Communication with other machines generally requires further
+modification to routing tables and/or ARP (Address Resolution
+Protocol) tables. In most cases the \fIdefaultroute\fR and/or
+\fIproxyarp\fR options are sufficient for this, but in some cases
+further intervention is required. The /etc/ppp/ip\-up script can be
+used for this.
+.LP
+Sometimes it is desirable to add a default route through the remote
+host, as in the case of a machine whose only connection to the
+Internet is through the ppp interface. The \fIdefaultroute\fR option
+causes pppd to create such a default route when IPCP comes up, and
+delete it when the link is terminated.
.LP
In some cases it is desirable to use proxy ARP, for example on a
server machine connected to a LAN, in order to allow other hosts to
-communicate with the remote host. The \fBproxyarp\fR option causes \fIpppd\fR
-to look for a network interface on the same subnet as the remote host
-(an interface supporting broadcast and ARP, which is up and not a
-point-to-point or loopback interface). If found, \fIpppd\fR creates a
+communicate with the remote host. The \fIproxyarp\fR option causes
+pppd to look for a network interface on the same subnet as the remote
+host (an interface supporting broadcast and ARP, which is up and not a
+point-to-point or loopback interface). If found, pppd creates a
permanent, published ARP entry with the IP address of the remote host
and the hardware address of the network interface found.
+.LP
+When the \fIdemand\fR option is used, the interface IP addresses have
+already been set at the point when IPCP comes up. If pppd has not
+been able to negotiate the same addresses that it used to configure
+the interface (for example when the peer is an ISP that uses dynamic
+IP address assignment), pppd has to change the interface IP addresses
+to the negotiated addresses. This may disrupt existing connections,
+and the use of demand dialling with peers that do dynamic IP address
+assignment is not recommended.
+.SH MULTILINK
+Multilink PPP provides the capability to combine two or more PPP links
+between a pair of machines into a single `bundle', which appears as a
+single virtual PPP link which has the combined bandwidth of the
+individual links. Currently, multilink PPP is only supported under
+Linux.
+.LP
+Pppd detects that the link it is controlling is connected to the same
+peer as another link using the peer's endpoint discriminator and the
+authenticated identity of the peer (if it authenticates itself). The
+endpoint discriminator is a block of data which is hopefully unique
+for each peer. Several types of data can be used, including
+locally-assigned strings of bytes, IP addresses, MAC addresses,
+randomly strings of bytes, or E\-164 phone numbers. The endpoint
+discriminator sent to the peer by pppd can be set using the endpoint
+option.
+.LP
+In some circumstances the peer may send no endpoint discriminator or a
+non-unique value. The bundle option adds an extra string which is
+added to the peer's endpoint discriminator and authenticated identity
+when matching up links to be joined together in a bundle. The bundle
+option can also be used to allow the establishment of multiple bundles
+between the local system and the peer. Pppd uses a TDB database in
+/var/run/pppd2.tdb to match up links.
+.LP
+Assuming that multilink is enabled and the peer is willing to
+negotiate multilink, then when pppd is invoked to bring up the first
+link to the peer, it will detect that no other link is connected to
+the peer and create a new bundle, that is, another ppp network
+interface unit. When another pppd is invoked to bring up another link
+to the peer, it will detect the existing bundle and join its link to
+it.
+.LP
+If the first link terminates (for example, because of a hangup or a
+received LCP terminate-request) the bundle is not destroyed unless
+there are no other links remaining in the bundle. Rather than
+exiting, the first pppd keeps running after its link terminates, until
+all the links in the bundle have terminated. If the first pppd
+receives a SIGTERM or SIGINT signal, it will destroy the bundle and
+send a SIGHUP to the pppd processes for each of the links in the
+bundle. If the first pppd receives a SIGHUP signal, it will terminate
+its link but not the bundle.
+.LP
+Note: demand mode is not currently supported with multilink.
.SH EXAMPLES
.LP
-In the simplest case, you can connect the serial ports of two machines
-and issue a command like
+The following examples assume that the /etc/ppp/options file contains
+the \fIauth\fR option (as in the default /etc/ppp/options file in the
+ppp distribution).
+.LP
+Probably the most common use of pppd is to dial out to an ISP. This
+can be done with a command such as
.IP
-pppd /dev/ttya 9600 passive
+pppd call isp
.LP
-to each machine, assuming there is no \fIgetty\fR running on the
-serial ports. If one machine has a \fIgetty\fR running, you can use
-\fIkermit\fR or \fItip\fR on the other machine to log in to the first
-machine and issue a command like
+where the /etc/ppp/peers/isp file is set up by the system
+administrator to contain something like this:
.IP
-pppd passive
+ttyS0 19200 crtscts
+.br
+connect '/usr/sbin/chat \-v \-f /etc/ppp/chat\-isp'
+.br
+noauth
.LP
-Then exit from the communications program (making sure the connection
-isn't dropped), and issue a command like
+In this example, we are using chat to dial the ISP's modem and go
+through any logon sequence required. The /etc/ppp/chat\-isp file
+contains the script used by chat; it could for example contain
+something like this:
.IP
-pppd /dev/ttya 9600
+ABORT "NO CARRIER"
+.br
+ABORT "NO DIALTONE"
+.br
+ABORT "ERROR"
+.br
+ABORT "NO ANSWER"
+.br
+ABORT "BUSY"
+.br
+ABORT "Username/Password Incorrect"
+.br
+"" "at"
+.br
+OK "at&d0&c1"
+.br
+OK "atdt2468135"
+.br
+"name:" "^Umyuserid"
+.br
+"word:" "\\qmypassword"
+.br
+"ispts" "\\q^Uppp"
+.br
+"~\-^Uppp\-~"
.LP
-The process of logging in to the other machine and starting \fIpppd\fR
-can be automated by using the \fBconnect\fR option to run \fIchat\fR,
-for example:
+See the chat(8) man page for details of chat scripts.
+.LP
+Pppd can also be used to provide a dial-in ppp service for users. If
+the users already have login accounts, the simplest way to set up the
+ppp service is to let the users log in to their accounts and run pppd
+(installed setuid-root) with a command such as
+.IP
+pppd proxyarp
+.LP
+To allow a user to use the PPP facilities, you need to allocate an IP
+address for that user's machine and create an entry in
+/etc/ppp/pap\-secrets, /etc/ppp/chap\-secrets, or /etc/ppp/srp\-secrets
+(depending on which authentication method the PPP implementation on
+the user's machine supports), so that the user's machine can
+authenticate itself. For example, if Joe has a machine called
+"joespc" that is to be allowed to dial in to the machine called
+"server" and use the IP address joespc.my.net, you would add an entry
+like this to /etc/ppp/pap\-secrets or /etc/ppp/chap\-secrets:
.IP
-pppd /dev/ttya 38400 connect 'chat "" "" "login:" "username"
-"Password:" "password" "% " "exec pppd passive"'
+joespc server "joe's secret" joespc.my.net
+.LP
+(See srp\-entry(8) for a means to generate the server's entry when
+SRP\-SHA1 is in use.)
+Alternatively, you can create a username called (for example) "ppp",
+whose login shell is pppd and whose home directory is /etc/ppp.
+Options to be used when pppd is run this way can be put in
+/etc/ppp/.ppprc.
.LP
If your serial connection is any more complicated than a piece of
wire, you may need to arrange for some control characters to be
escaped. In particular, it is often useful to escape XON (^Q) and
-XOFF (^S), using \fBasyncmap a0000\fR. If the path includes a telnet,
-you probably should escape ^] as well (\fBasyncmap 200a0000\fR).
-Don't use an rlogin in the path - many implementations are not
-transparent; they will remove the sequence [0xff, 0xff, 0x73, 0x73,
-followed by any 8 bytes] from the stream.
+XOFF (^S), using \fIasyncmap a0000\fR. If the path includes a telnet,
+you probably should escape ^] as well (\fIasyncmap 200a0000\fR). If
+the path includes an rlogin, you will need to use the \fIescape ff\fR
+option on the end which is running the rlogin client, since many
+rlogin implementations are not transparent; they will remove the
+sequence [0xff, 0xff, 0x73, 0x73, followed by any 8 bytes] from the
+stream.
.SH DIAGNOSTICS
.LP
-Messages are sent to the syslog daemon using facility
-LOG_DAEMON unless
-.I pppd
-has been compiled with debugging code. In this case the logging
-facility used will be LOG_LOCAL2 in order to allow separation of the debug
-output from the other daemons using the LOG_DAEMON facility. You can
-override this by defining the macro LOG_PPP to the desired facility
-and recompiling. In order to see the error and debug messages, you
-will need to edit your /etc/syslog.conf file to direct the messages to
-the desired output device or file.
-.LP
-If enabled at compile time, debugging printout can be enabled by
-setting the -d or debug flag on the command line, or by sending a
-SIGUSR1 to the
-.I pppd
-process.
-Debugging may be disabled by sending a SIGUSR2 to the
-.I pppd
-process.
-.SH FILES
-.TP
-.B /var/run/ppp\fIn\fB.pid \fR(BSD), \fB/etc/ppp/ppp\fIn\fB.pid \fR(SunOS)
-Process-ID for \fIpppd\fR process on ppp interface unit \fIn\fR.
+Messages are sent to the syslog daemon using facility LOG_DAEMON.
+(This can be overridden by recompiling pppd with the macro
+LOG_PPP defined as the desired facility.) See the syslog(8)
+documentation for details of where the syslog daemon will write the
+messages. On most systems, the syslog daemon uses the
+/etc/syslog.conf file to specify the destination(s) for syslog
+messages. You may need to edit that file to suit.
+.LP
+The \fIdebug\fR option causes the contents of all control packets sent
+or received to be logged, that is, all LCP, PAP, CHAP, EAP, or IPCP packets.
+This can be useful if the PPP negotiation does not succeed or if
+authentication fails.
+If debugging is enabled at compile time, the \fIdebug\fR option also
+causes other debugging messages to be logged.
+.LP
+Debugging can also be enabled or disabled by sending a SIGUSR1 signal
+to the pppd process. This signal acts as a toggle.
+.SH EXIT STATUS
+The exit status of pppd is set to indicate whether any error was
+detected, or the reason for the link being terminated. The values
+used are:
+.TP
+.B 0
+Pppd has detached, or otherwise the connection was successfully
+established and terminated at the peer's request.
+.TP
+.B 1
+An immediately fatal error of some kind occurred, such as an essential
+system call failing, or running out of virtual memory.
.TP
-.B /etc/ppp/pap-secrets
-Usernames, passwords and IP addresses for PAP authentication.
+.B 2
+An error was detected in processing the options given, such as two
+mutually exclusive options being used.
+.TP
+.B 3
+Pppd is not setuid-root and the invoking user is not root.
+.TP
+.B 4
+The kernel does not support PPP, for example, the PPP kernel driver is
+not included or cannot be loaded.
+.TP
+.B 5
+Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP
+signal.
+.TP
+.B 6
+The serial port could not be locked.
+.TP
+.B 7
+The serial port could not be opened.
+.TP
+.B 8
+The connect script failed (returned a non-zero exit status).
+.TP
+.B 9
+The command specified as the argument to the \fIpty\fR option could
+not be run.
+.TP
+.B 10
+The PPP negotiation failed, that is, it didn't reach the point where
+at least one network protocol (e.g. IP) was running.
+.TP
+.B 11
+The peer system failed (or refused) to authenticate itself.
+.TP
+.B 12
+The link was established successfully and terminated because it was
+idle.
+.TP
+.B 13
+The link was established successfully and terminated because the
+connect time limit was reached.
+.TP
+.B 14
+Callback was negotiated and an incoming call should arrive shortly.
+.TP
+.B 15
+The link was terminated because the peer is not responding to echo
+requests.
+.TP
+.B 16
+The link was terminated by the modem hanging up.
+.TP
+.B 17
+The PPP negotiation failed because serial loopback was detected.
+.TP
+.B 18
+The init script failed (returned a non-zero exit status).
+.TP
+.B 19
+We failed to authenticate ourselves to the peer.
+.SH SCRIPTS
+Pppd invokes scripts at various stages in its processing which can be
+used to perform site-specific ancillary processing. These scripts are
+usually shell scripts, but could be executable code files instead.
+Pppd does not wait for the scripts to finish (except for the ip-pre-up
+script). The scripts are
+executed as root (with the real and effective user-id set to 0), so
+that they can do things such as update routing tables or run
+privileged daemons. Be careful that the contents of these scripts do
+not compromise your system's security. Pppd runs the scripts with
+standard input, output and error redirected to /dev/null, and with an
+environment that is empty except for some environment variables that
+give information about the link. The environment variables that pppd
+sets are:
+.TP
+.B DEVICE
+The name of the serial tty device being used.
+.TP
+.B IFNAME
+The name of the network interface being used.
+.TP
+.B IPLOCAL
+The IP address for the local end of the link. This is only set when
+IPCP has come up.
+.TP
+.B IPREMOTE
+The IP address for the remote end of the link. This is only set when
+IPCP has come up.
+.TP
+.B PEERNAME
+The authenticated name of the peer. This is only set if the peer
+authenticates itself.
+.TP
+.B SPEED
+The baud rate of the tty device.
+.TP
+.B ORIG_UID
+The real user-id of the user who invoked pppd.
+.TP
+.B PPPLOGNAME
+The username of the real user-id that invoked pppd. This is always set.
+.P
+For the ip-down and auth-down scripts, pppd also sets the following
+variables giving statistics for the connection:
+.TP
+.B CONNECT_TIME
+The number of seconds from when the PPP negotiation started until the
+connection was terminated.
+.TP
+.B BYTES_SENT
+The number of bytes sent (at the level of the serial port) during the
+connection.
+.TP
+.B BYTES_RCVD
+The number of bytes received (at the level of the serial port) during
+the connection.
+.TP
+.B LINKNAME
+The logical name of the link, set with the \fIlinkname\fR option.
+.TP
+.B DNS1
+If the peer supplies DNS server addresses, this variable is set to the
+first DNS server address supplied (whether or not the usepeerdns
+option was given).
+.TP
+.B DNS2
+If the peer supplies DNS server addresses, this variable is set to the
+second DNS server address supplied (whether or not the usepeerdns
+option was given).
+.P
+Pppd invokes the following scripts, if they exist. It is not an error
+if they don't exist.
+.TP
+.B /etc/ppp/auth\-up
+A program or script which is executed after the remote system
+successfully authenticates itself. It is executed with the parameters
+.IP
+\fIinterface\-name peer\-name user\-name tty\-device speed\fR
+.IP
+Note that this script is not executed if the peer doesn't authenticate
+itself, for example when the \fInoauth\fR option is used.
+.TP
+.B /etc/ppp/auth\-down
+A program or script which is executed when the link goes down, if
+/etc/ppp/auth\-up was previously executed. It is executed in the same
+manner with the same parameters as /etc/ppp/auth\-up.
+.TP
+.B /etc/ppp/ip\-pre\-up
+A program or script which is executed just before the ppp network
+interface is brought up. It is executed with the same parameters as
+the ip\-up script (below). At this point the interface exists and has
+IP addresses assigned but is still down. This can be used to
+add firewall rules before any IP traffic can pass through the
+interface. Pppd will wait for this script to finish before bringing
+the interface up, so this script should run quickly.
+.TP
+.B /etc/ppp/ip\-up
+A program or script which is executed when the link is available for
+sending and receiving IP packets (that is, IPCP has come up). It is
+executed with the parameters
+.IP
+\fIinterface\-name tty\-device speed local\-IP\-address
+remote\-IP\-address ipparam\fR
+.TP
+.B /etc/ppp/ip\-down
+A program or script which is executed when the link is no longer
+available for sending and receiving IP packets. This script can be
+used for undoing the effects of the /etc/ppp/ip\-up and
+/etc/ppp/ip\-pre\-up scripts. It is
+invoked in the same manner and with the same parameters as the ip\-up
+script.
+.TP
+.B /etc/ppp/ipv6\-up
+Like /etc/ppp/ip\-up, except that it is executed when the link is available
+for sending and receiving IPv6 packets. It is executed with the parameters
+.IP
+\fIinterface\-name tty\-device speed local\-link\-local\-address
+remote\-link\-local\-address ipparam\fR
+.TP
+.B /etc/ppp/ipv6\-down
+Similar to /etc/ppp/ip\-down, but it is executed when IPv6 packets can no
+longer be transmitted on the link. It is executed with the same parameters
+as the ipv6\-up script.
+.TP
+.B /etc/ppp/ipx\-up
+A program or script which is executed when the link is available for
+sending and receiving IPX packets (that is, IPXCP has come up). It is
+executed with the parameters
+.IP
+\fIinterface\-name tty\-device speed network\-number local\-IPX\-node\-address
+remote\-IPX\-node\-address local\-IPX\-routing\-protocol remote\-IPX\-routing\-protocol
+local\-IPX\-router\-name remote\-IPX\-router\-name ipparam pppd\-pid\fR
+.IP
+The local\-IPX\-routing\-protocol and remote\-IPX\-routing\-protocol field
+may be one of the following:
+.IP
+NONE to indicate that there is no routing protocol
+.br
+RIP to indicate that RIP/SAP should be used
+.br
+NLSP to indicate that Novell NLSP should be used
+.br
+RIP NLSP to indicate that both RIP/SAP and NLSP should be used
+.TP
+.B /etc/ppp/ipx\-down
+A program or script which is executed when the link is no longer
+available for sending and receiving IPX packets. This script can be
+used for undoing the effects of the /etc/ppp/ipx\-up script. It is
+invoked in the same manner and with the same parameters as the ipx\-up
+script.
+.SH FILES
.TP
-.B /etc/ppp/chap-secrets
-Names, secrets and IP addresses for CHAP authentication.
+.B /var/run/ppp\fIn\fB.pid \fR(BSD or Linux), \fB/etc/ppp/ppp\fIn\fB.pid \fR(others)
+Process-ID for pppd process on ppp interface unit \fIn\fR.
+.TP
+.B /var/run/ppp\-\fIname\fB.pid \fR(BSD or Linux),
+\fB/etc/ppp/ppp\-\fIname\fB.pid \fR(others)
+Process-ID for pppd process for logical link \fIname\fR (see the
+\fIlinkname\fR option).
+.TP
+.B /var/run/pppd2.tdb
+Database containing information about pppd processes, interfaces and
+links, used for matching links to bundles in multilink operation. May
+be examined by external programs to obtain information about running
+pppd instances, the interfaces and devices they are using, IP address
+assignments, etc.
+.B /etc/ppp/pap\-secrets
+Usernames, passwords and IP addresses for PAP authentication. This
+file should be owned by root and not readable or writable by any other
+user. Pppd will log a warning if this is not the case.
+.TP
+.B /etc/ppp/chap\-secrets
+Names, secrets and IP addresses for CHAP/MS\-CHAP/MS\-CHAPv2 authentication.
+As for /etc/ppp/pap\-secrets, this file should be owned by root and not
+readable or writable by any other user. Pppd will log a warning if
+this is not the case.
+.TP
+.B /etc/ppp/srp\-secrets
+Names, secrets, and IP addresses for EAP authentication. As for
+/etc/ppp/pap\-secrets, this file should be owned by root and not
+readable or writable by any other user. Pppd will log a warning if
+this is not the case.
+.TP
+.B ~/.ppp_pseudonym
+Saved client-side SRP\-SHA1 pseudonym. See the \fIsrp\-use\-pseudonym\fR
+option for details.
.TP
.B /etc/ppp/options
-System default options for
-.I pppd,
-read before user default options or command-line options.
-.TP
-.B $HOME/.ppprc
-User default options, read before command-line options.
+System default options for pppd, read before user default options or
+command-line options.
+.TP
+.B ~/.ppprc
+User default options, read before /etc/ppp/options.\fIttyname\fR.
+.TP
+.B /etc/ppp/options.\fIttyname
+System default options for the serial port being used, read after
+~/.ppprc. In forming the \fIttyname\fR part of this
+filename, an initial /dev/ is stripped from the port name (if
+present), and any slashes in the remaining part are converted to
+dots.
+.TP
+.B /etc/ppp/peers
+A directory containing options files which may contain privileged
+options, even if pppd was invoked by a user other than root. The
+system administrator can create options files in this directory to
+permit non-privileged users to dial out without requiring the peer to
+authenticate, but only to certain trusted peers.
.SH SEE ALSO
+.BR chat (8),
+.BR pppstats (8)
.TP
.B RFC1144
Jacobson, V.
-.I Compressing TCP/IP headers for low-speed serial links.
-1990 February.
+\fICompressing TCP/IP headers for low-speed serial links.\fR
+February 1990.
.TP
.B RFC1321
Rivest, R.
.I The MD5 Message-Digest Algorithm.
-1992 April.
-.TP
-.B RFC1331
-Simpson, W.A.
-.I Point\-to\-Point Protocol (PPP) for the transmission of multi\-protocol
-.I datagrams over point\-to\-point links.
-1992 May.
+April 1992.
.TP
.B RFC1332
McGregor, G.
.I PPP Internet Protocol Control Protocol (IPCP).
-1992 May.
+May 1992.
.TP
.B RFC1334
Lloyd, B.; Simpson, W.A.
.I PPP authentication protocols.
-1992 October.
+October 1992.
+.TP
+.B RFC1661
+Simpson, W.A.
+.I The Point-to-Point Protocol (PPP).
+July 1994.
+.TP
+.B RFC1662
+Simpson, W.A.
+.I PPP in HDLC-like Framing.
+July 1994.
+.TP
+.B RFC2284
+Blunk, L.; Vollbrecht, J.,
+.I PPP Extensible Authentication Protocol (EAP).
+March 1998.
+.TP
+.B RFC2472
+Haskin, D.
+.I IP Version 6 over PPP
+December 1998.
+.TP
+.B RFC2945
+Wu, T.,
+.I The SRP Authentication and Key Exchange System
+September 2000.
+.TP
+.B draft\-ietf\-pppext\-eap\-srp\-03.txt
+Carlson, J.; et al.,
+.I EAP SRP\-SHA1 Authentication Protocol.
+July 2001.
.SH NOTES
-The following signals have the specified effect when sent to the
-.I pppd
-process.
+Some limited degree of control can be exercised over a running pppd
+process by sending it a signal from the list below.
.TP
.B SIGINT, SIGTERM
-These signals cause \fIpppd\fR to terminate the link (by closing LCP),
-restore the serial device settings, and exit.
+These signals cause pppd to terminate the link (by closing LCP),
+restore the serial device settings, and exit. If a connector or
+disconnector process is currently running, pppd will send the same
+signal to its process group, so as to terminate the connector or
+disconnector process.
.TP
.B SIGHUP
-Indicates that the physical layer has been disconnected. \fIpppd\fR
-will attempt to restore the serial device settings (this may produce
-error messages on Suns), and then exit.
-.SH BUGS
-The use of the modem control lines and the effects of the \fBmodem\fR
-and \fBlocal\fR options are not well defined.
+This signal causes pppd to terminate the link, restore the serial
+device settings, and close the serial device. If the \fIpersist\fR or
+\fIdemand\fR option has been specified, pppd will try to reopen the
+serial device and start another connection (after the holdoff period).
+Otherwise pppd will exit. If this signal is received during the
+holdoff period, it causes pppd to end the holdoff period immediately.
+If a connector or disconnector process is running, pppd will send the
+same signal to its process group.
+.TP
+.B SIGUSR1
+This signal toggles the state of the \fIdebug\fR option.
+.TP
+.B SIGUSR2
+This signal causes pppd to renegotiate compression. This can be
+useful to re-enable compression after it has been disabled as a result
+of a fatal decompression error. (Fatal decompression errors generally
+indicate a bug in one or other implementation.)
+
.SH AUTHORS
+Paul Mackerras (paulus@samba.org), based on earlier work by
Drew Perkins,
Brad Clements,
Karl Fox,
Greg Christy,
-Brad Parker (brad@fcr.com),
-Paul Mackerras (paulus@cs.anu.edu.au)
+and
+Brad Parker.
+
+.SH COPYRIGHT
+Pppd is copyrighted and made available under conditions which provide
+that it may be copied and used in source or binary forms provided that
+the conditions listed below are met. Portions of pppd are covered by
+the following copyright notices:
+.LP
+Copyright (c) 1984-2000 Carnegie Mellon University. All rights
+reserved.
+.br
+Copyright (c) 1993-2004 Paul Mackerras. All rights reserved.
+.br
+Copyright (c) 1995 Pedro Roque Marques. All rights reserved.
+.br
+Copyright (c) 1995 Eric Rosenquist. All rights reserved.
+.br
+Copyright (c) 1999 Tommi Komulainen. All rights reserved.
+.br
+Copyright (C) Andrew Tridgell 1999
+.br
+Copyright (c) 2000 by Sun Microsystems, Inc. All rights reserved.
+.br
+Copyright (c) 2001 by Sun Microsystems, Inc. All rights reserved.
+.br
+Copyright (c) 2002 Google, Inc. All rights reserved.
+.LP
+The copyright notices contain the following statements.
+.LP
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
+.LP
+1. Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+.LP
+2. Redistributions in binary form must reproduce the above copyright
+ notice, this list of conditions and the following disclaimer in
+ the documentation and/or other materials provided with the
+ distribution.
+.LP
+3. The name "Carnegie Mellon University" must not be used to
+ endorse or promote products derived from this software without
+ prior written permission. For permission or any legal
+ details, please contact
+.br
+ Office of Technology Transfer
+.br
+ Carnegie Mellon University
+.br
+ 5000 Forbes Avenue
+.br
+ Pittsburgh, PA 15213-3890
+.br
+ (412) 268-4387, fax: (412) 268-7395
+.br
+ tech-transfer@andrew.cmu.edu
+.LP
+3b. The name(s) of the authors of this software must not be used to
+ endorse or promote products derived from this software without
+ prior written permission.
+.LP
+4. Redistributions of any form whatsoever must retain the following
+ acknowledgements:
+.br
+ "This product includes software developed by Computing Services
+ at Carnegie Mellon University (http://www.cmu.edu/computing/)."
+.br
+ "This product includes software developed by Paul Mackerras
+ <paulus@samba.org>".
+.br
+ "This product includes software developed by Pedro Roque Marques
+ <pedro_m@yahoo.com>".
+.br
+ "This product includes software developed by Tommi Komulainen
+ <Tommi.Komulainen@iki.fi>".
+.LP
+CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE
+FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+.LP
+THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
+THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
+SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
projects / ppp.git / blobdiff