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спецификации, руководства, описания, API
Spec-Zone .ru
спецификации, руководства, описания, API
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PPPD(8)                                                                                              PPPD(8)



NAME
       pppd - Point-to-Point Protocol Daemon

SYNOPSIS
       pppd [ options ]

DESCRIPTION
       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 pppd daemon works together with the kernel PPP  driver
       to  establish and maintain a PPP link with another system (called the peer) 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.

FREQUENTLY USED OPTIONS
       ttyname
              Use the serial port called ttyname to communicate  with  the  peer.   The  string  "/dev/"  is
              prepended  to  ttyname 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  ter-minal, terminal,
              minal,  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.

       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.

       asyncmap map
              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 asyncmap options are given, the values are ORed together.
              If  no  asyncmap 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 escape option.

       auth   Require the peer to authenticate  itself  before  allowing  network  packets  to  be  sent  or
              received.   This  option  is  the  default if the system has a default route.  If neither this
              option nor the noauth option is specified, pppd will only allow the peer to use  IP  addresses
              to which the system does not already have a route.

       call name
              Read  options  from  the  file /etc/ppp/peers/name.  This file may contain privileged options,
              such as noauth, even if pppd is not being run by root.  The name string may not begin  with  /
              or include .. as a pathname component.  The format of the options file is described below.

       connect script
              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.

       crtscts
              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 crtscts, the nocrtscts, the  cdtrcts  nor
              the  nocdtrcts  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 sus-pend suspend
              pend 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.

       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 bro-ken. broken.
              ken.  This option is privileged if the nodefaultroute option has been specified.

       disconnect script
              Execute the command specified by script, 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 over-ridden overridden
              ridden by a non-privileged user.

       escape xx,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 escape option, unlike the asyncmap 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.

       file name
              Read options from file name (the format is described below).  The file must be readable by the
              user who has invoked pppd.

       init script
              Execute the command specified by script, 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 nonprivileged
              privileged user.

       lock   Specifies  that  pppd  should  create  a  UUCP-style lock file for the serial device to ensure
              exclusive access to the device.

       mru n  Set the MRU [Maximum Receive Unit] value to n. Pppd will ask the peer to send  packets  of  no
              more  than  n  bytes.   The  value of n 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.

       mtu n  Set  the MTU [Maximum Transmit Unit] value to n.  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 n bytes through the PPP network interface.  Note that for the IPv6 protocol, the MTU
              must be at least 1280.

       passive
              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.

OPTIONS
       <local_IP_address>:<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. 150.234.56.78).
              The default local address is the (first) IP address of  the  system  (unless  the  noipdefault
              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  ipcp-accept-local  and/or  ipcp-accept-remote  options  are
              given, respectively.

       ipv6 <local_interface_identifier>,<remote_interface_identifier>
              Set  the local and/or remote 64-bit interface identifier. Either one may be omitted. The iden-tifier identifier
              tifier must be specified in standard ascii notation of IPv6 addresses (e.g.  ::dead:beef).  If
              the  ipv6cp-use-ipaddr  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,  ipv6cp-use-persistent  option  can  be  used  to  replace  the  ipv6
              <local>,<remote> option. Otherwise the identifier is randomized.

       active-filter filter-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-dialing mode.  This option is useful in conjunction with the idle 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  filter-expression filterexpression
              expression syntax is as described for tcpdump(1), except that qualifiers which are inappropri-ate inappropriate
              ate for a PPP link, such as ether and arp, are not permitted.  Generally the filter expression
              should  be enclosed in single-quotes to prevent whitespace in the expression from being inter-preted interpreted
              preted 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  inbound
              and outbound qualifiers.

       allow-ip address(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).

       allow-number number
              Allow  peers  to connect from the given telephone number.  A trailing `*' character will match
              all numbers beginning with the leading part.

       bsdcomp nr,nt
              Request that the peer compress packets that it sends, using the BSD-Compress  scheme,  with  a
              maximum  code  size  of nr bits, and agree to compress packets sent to the peer with a maximum
              code size of nt bits.  If nt is not specified, it defaults to the value given for nr.   Values
              in the range 9 to 15 may be used for nr and nt; larger values give better compression but con-sume consume
              sume more kernel memory for compression dictionaries.  Alternatively, a value of 0 for  nr  or
              nt disables compression in the corresponding direction.  Use nobsdcomp or bsdcomp _ to disable
              BSD-Compress compression entirely.

       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 crtscts, the nocrtscts, the cdtrcts nor the nocdtrcts 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.

       chap-interval n
              If this option is given, pppd will rechallenge the peer every n seconds.

       chap-max-challenge n
              Set the maximum number of CHAP challenge transmissions to n (default 10).

       chap-restart n
              Set  the  CHAP  restart interval (retransmission timeout for challenges) to n seconds (default
              3).

       connect-delay n
              Wait for up n 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  sec-ond). second).
              ond).  This wait period only applies if the connect or pty option is used.

       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  daemon and level debug.  This information can be directed to a file by
              setting up /etc/syslog.conf appropriately (see syslog.conf(5)).

       default-asyncmap
              Disable asyncmap negotiation, forcing all control characters to be escaped for both the trans-mit transmit
              mit and the receive direction.

       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.

       deflate nr,nt
              Request that the peer compress packets that it sends, using the Deflate scheme, with a maximum
              window size of 2**nr bytes, and agree to compress packets sent to the peer with a maximum win-dow window
              dow size of 2**nt bytes.  If nt is not specified, it defaults to the value given for nr.  Val-ues Values
              ues  in the range 9 to 15 may be used for nr and nt; larger values give better compression but
              consume more kernel memory for compression dictionaries.  Alternatively, a value of 0  for  nr
              or nt disables compression in the corresponding direction.  Use nodeflate or deflate _ to dis-able disable
              able Deflate compression entirely.  (Note: pppd requests Deflate compression in preference  to
              BSD-Compress if the peer can do either.)

       demand Initiate  the  link  only on demand, i.e. when data traffic is present.  With this option, the
              remote IP address must be specified by the user on the command line or  in  an  options  file.
              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 demand option implies the persist option.  If this behaviour is not desired, use the  nop-ersist nopersist
              ersist  option  after the demand option.  The idle and holdoff options are also useful in con-juction conjuction
              juction with the demand option.

       domain 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 could specify domain Quotron.COM.   Pppd  would  then  use  the  name
              porsche.Quotron.COM  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.

       dryrun With the dryrun 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.

       dump   With the dump option, pppd will print out all the option values which  have  been  set.   This
              option is like the dryrun option except that pppd proceeds as normal rather than exiting.

       endpoint <epdisc>
              Sets the endpoint discriminator sent by the local machine to the peer during multilink negoti-ation negotiation
              ation to <epdisc>.  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 null or of the form type:value, where type is a
              decimal number or one of the strings local, IP, MAC, magic, or phone.   The  value  is  an  IP
              address in dotted-decimal notation for the IP type, or a string of bytes in hexadecimal, sepa-rated separated
              rated 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.

       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.

       holdoff n
              Specifies  how  many  seconds to wait before re-initiating the link after it terminates.  This
              option only has any effect if the persist or demand option is used.  The holdoff period is not
              applied if the link was terminated because it was idle.

       idle n Specifies  that  pppd  should  disconnect if the link is idle for n 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 persist option without the demand option.  If the active-filter
              option is given, data packets which are rejected by the specified activity filter  also  count
              as the link being idle.

       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.

       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.

       ipcp-max-configure n
              Set the maximum number of IPCP configure-request transmissions to n (default 10).

       ipcp-max-failure n
              Set  the  maximum  number  of  IPCP configure-NAKs returned before starting to send configure-Rejects configureRejects
              Rejects instead to n (default 10).

       ipcp-max-terminate n
              Set the maximum number of IPCP terminate-request transmissions to n (default 3).

       ipcp-restart n
              Set the IPCP restart interval (retransmission timeout) to n seconds (default 3).

       ipparam string
              Provides an extra parameter to the ip-up and ip-down scripts.  If this option  is  given,  the
              string supplied is given as the 6th parameter to those scripts.

       ipv6cp-max-configure n
              Set the maximum number of IPv6CP configure-request transmissions to n (default 10).

       ipv6cp-max-failure n
              Set  the  maximum  number of IPv6CP configure-NAKs returned before starting to send configure-Rejects configureRejects
              Rejects instead to n (default 10).

       ipv6cp-max-terminate n
              Set the maximum number of IPv6CP terminate-request transmissions to n (default 3).

       ipv6cp-restart n
              Set the IPv6CP restart interval (retransmission timeout) to n seconds (default 3).

       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.

       ipx-network n
              Set  the  IPX  network  number in the IPXCP configure request frame to n, a hexadecimal number
              (without a leading 0x).  There is no valid default.  If this option is not specified, the net-work network
              work  number is obtained from the peer.  If the peer does not have the network number, the IPX
              protocol will not be started.

       ipx-node n:m
              Set the IPX node numbers. The two node numbers are separated from  each  other  with  a  colon
              character. The first number n is the local node number. The second number m 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.

       ipx-router-name <string>
              Set the name of the router. This is a string and is sent to the peer as information data.

       ipx-routing n
              Set the routing protocol to be received by this option. More than one instance of  ipx-routing
              may  be specified. The 'none' option (0) may be specified as the only instance of ipx-routing.
              The values may be _ for NONE, 2 for RIP/SAP, and 4 for NLSP.

       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.

       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.

       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.

       ipxcp-max-configure n
              Set the maximum number of IPXCP configure request frames which the system will send to n.  The
              default is 10.

       ipxcp-max-failure n
              Set  the maximum number of IPXCP NAK frames which the local system will send before it rejects
              the options. The default value is 3.

       ipxcp-max-terminate n
              Set the maximum nuber of IPXCP terminate request frames before the local system considers that
              the peer is not listening to them. The default value is 3.

       kdebug n
              Enable  debugging code in the kernel-level PPP driver.  The argument values depend on the spe-cific specific
              cific 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  mes-sages, messages,
              sages,  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 ker-nel kernel
              nel  are logged by syslog(1) to a file as directed in the /etc/syslog.conf configuration file.

       ktune  Enables pppd to alter kernel settings as appropriate.  Under Linux, pppd will enable  IP  for-warding forwarding
              warding (i.e. set /proc/sys/net/ipv4/ip_forward to 1) if the proxyarp 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.

       lcp-echo-failure n
              If this option is given, pppd will presume the peer to be dead if n LCP echo-requests are sent
              without receiving a valid LCP echo-reply.  If this happens, pppd will  terminate  the  connec-tion. connection.
              tion.  Use of this option requires a non-zero value for the lcp-echo-interval 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 avail-able. available.
              able.

       lcp-echo-interval n
              If this option is given, pppd will send an LCP echo-request frame to the peer every n seconds.
              Normally  the  peer  should respond to the echo-request by sending an echo-reply.  This option
              can be used with the lcp-echo-failure option to detect that the peer is no longer connected.

       lcp-max-configure n
              Set the maximum number of LCP configure-request transmissions to n (default 10).

       lcp-max-failure n
              Set the maximum number of LCP configure-NAKs  returned  before  starting  to  send  configure-Rejects configureRejects
              Rejects instead to n (default 10).

       lcp-max-terminate n
              Set the maximum number of LCP terminate-request transmissions to n (default 3).

       lcp-restart n
              Set the LCP restart interval (retransmission timeout) to n seconds (default 3).

       linkname name
              Sets  the  logical  name  of  the link to name.  Pppd will create a file named ppp-name.pid 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.

       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.

       logfd n
              Send log messages to file descriptor n.  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 log-file logfile
              file 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.

       logfile filename
              Append log messages to the file filename (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.

       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.

       maxconnect n
              Terminate the connection when it has been available for network traffic for n seconds (i.e.  n
              seconds after the first network control protocol comes up).

       maxfail n
              Terminate  after  n consecutive failed connection attempts.  A value of 0 means no limit.  The
              default value is 10.

       modem  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 crtscts option.

       mp     Enables the use of PPP multilink; this is an alias for the `multilink' option.  This option is
              currently only available under Linux.

       mppe-stateful
              Allow  MPPE to use stateful mode.  Stateless mode is still attempted first.  The default is to
              disallow stateful mode.

       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 mul-tilink multilink
              tilink is enabled (see the multilink option).

       mrru n Sets the Maximum Reconstructed Receive Unit to n.  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).

       ms-dns <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 sec-ondary secondary
              ondary DNS address.  (This option was present in some older versions of pppd  under  the  name
              dns-addr.)

       ms-wins <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.

       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 exist-ing existing
              ing 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.

       name name
              Set the name of the local system for authentication purposes to name.  This  is  a  privileged
              option.   With  this  option,  pppd will use lines in the secrets files which have name as the
              second field when looking for a secret to use in authenticating the peer.  In addition, unless
              overridden  with  the  user  option,  name  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 name.)

       noaccomp
              Disable Address/Control compression in both directions (send and receive).

       noauth Do not require the peer to authenticate itself.  This option is privileged.

       nobsdcomp
              Disables  BSD-Compress  compression;  pppd will not request or agree to compress packets using
              the BSD-Compress scheme.

       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.

       nocrtscts
              Disable  hardware  flow control (i.e. RTS/CTS) on the serial port.  If neither the crtscts nor
              the nocrtscts nor the cdtrcts nor the nocdtrcts option is given,  the  hardware  flow  control
              setting for the serial port is left unchanged.

       nocdtrcts
              This  option  is  a  synonym for nocrtscts. Either of these options will disable both forms of
              hardware flow control.

       nodefaultroute
              Disable the defaultroute 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.

       nodeflate
              Disables Deflate compression; pppd will not request or agree to  compress  packets  using  the
              Deflate scheme.

       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.

       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.

       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.

       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.

       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).

       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.

       noktune
              Opposite of the ktune option; disables pppd from changing system settings.

       nolog  Do not send log messages to a file or file descriptor.  This option cancels the logfd and log-file logfile
              file options.

       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.

       nomp   Disables the use of PPP multilink.  This option is currently only available under Linux.

       nomppe Disables MPPE (Microsoft Point to Point Encryption).  This is the default.

       nomppe-40
              Disable 40-bit encryption with MPPE.

       nomppe-128
              Disable 128-bit encryption with MPPE.

       nomppe-stateful
              Disable MPPE stateful mode.  This is the default.

       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.

       nomultilink
              Disables the use of PPP multilink.  This option is currently only available under Linux.

       nopcomp
              Disable protocol field compression negotiation in both the receive and the transmit direction.

       nopersist
              Exit once a connection has been made and terminated.  This is the default unless  the  persist
              or demand option has been specified.

       nopredictor1
              Do not accept or agree to Predictor-1 compression.

       noproxyarp
              Disable the proxyarp option.  The system administrator who wishes to prevent users from creat-ing creating
              ing proxy ARP entries with pppd can do so by placing this option in the /etc/ppp/options file.

       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 mas-ter master
              ter 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.

       novj   Disable Van Jacobson style TCP/IP header compression in both  the  transmit  and  the  receive
              direction.

       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.

       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.

       pap-max-authreq n
              Set the maximum number of PAP authenticate-request transmissions to n (default 10).

       pap-restart n
              Set the PAP restart interval (retransmission timeout) to n seconds (default 3).

       pap-timeout n
              Set  the  maximum  time  that pppd will wait for the peer to authenticate itself with PAP to n
              seconds (0 means no limit).

       pass-filter filter-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 dis-carded. discarded.
              carded.  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 filter-expression syntax
              is as described for tcpdump(1), except that qualifiers which are inappropriate for a PPP link,
              such  as ether and arp, 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 inbound and outbound qualifiers. This option is currently only available under Linux,  and
              requires  that the kernel was configured to include PPP filtering support (CONFIG_PPP_FILTER).

       password password-string
              Specifies the password to use for authenticating to the peer.  Use of this option is  discour-aged, discouraged,
              aged,  as  the  password is likely to be visible to other users on the system (for example, by
              using ps(1)).

       persist
              Do not exit after a connection is terminated; instead try to reopen the connection.  The  max-fail maxfail
              fail option still has an effect on persistent connections.

       plugin filename
              Load  the  shared  library object file filename as a plugin.  This is a privileged option.  If
              filename does not contain a slash (/), pppd will look in the  /usr/lib/pppd/version  directory
              for the plugin, where version is the version number of pppd (for example, 2.4.2).

       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.

       privgroup group-name
              Allows  members  of  group group-name to use privileged options.  This is a privileged option.
              Use of this option requires care as there is no guarantee that members  of  group-name  cannot
              use  pppd  to become root themselves.  Consider it equivalent to putting the members of group-name groupname
              name in the kmem or disk group.

       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.

       pty script
              Specifies that the command script 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 script 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 record option is used in conjuction with the pty option, the child process  will
              have pipes on its standard input and output.)

       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.

       record filename
              Specifies  that  pppd should record all characters sent and received to a file named filename.
              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.

       remotename name
              Set the assumed name of the remote system for authentication purposes to name.

       remotenumber number
              Set the assumed telephone number of the remote system for authentication purposes to number.

       refuse-chap
              With this option, pppd will not agree to authenticate itself to the peer using CHAP.

       refuse-mschap
              With this option, pppd will not agree to authenticate itself to the peer using MS-CHAP.

       refuse-mschap-v2
              With this option, pppd will not agree to authenticate itself to the peer using MS-CHAPv2.

       refuse-eap
              With this option, pppd will not agree to authenticate itself to the peer using EAP.

       refuse-pap
              With this option, pppd will not agree to authenticate itself to the peer using PAP.

       require-chap
              Require the peer to authenticate itself using CHAP [Challenge Handshake Authentication  Proto-col] Protocol]
              col] authentication.

       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.

       require-mppe-40
              Require the use of MPPE, with 40-bit encryption.

       require-mppe-128
              Require the use of MPPE, with 128-bit encryption.

       require-mschap
              Require  the peer to authenticate itself using MS-CHAP [Microsft Challenge Handshake Authenti-cation Authentication
              cation Protocol] authentication.

       require-mschap-v2
              Require the peer to authenticate itself using MS-CHAPv2 [Microsft Challenge Handshake  Authen-tication Authentication
              tication Protocol, Version 2] authentication.

       require-eap
              Require the peer to authenticate itself using EAP [Extensible Authentication Protocol] authen-tication. authentication.
              tication.

       require-pap
              Require the peer to authenticate itself using PAP [Password Authentication Protocol] authenti-cation. authentication.
              cation.

       show-password
              When  logging the contents of PAP packets, this option causes pppd to show the password string
              in the log message.

       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).

       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.

       unit num
              Sets the ppp unit number (for a ppp0 or ppp1 etc interface name) for outbound connections.

       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).

       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 name option).  This option is not normally
              needed since the name option is privileged.

       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.

       user name
              Sets the name used for authenticating the local system to the peer to name.

       vj-max-slots n
              Sets the number of connection slots to be used by the Van Jacobson TCP/IP  header  compression
              and decompression code to n, which must be between 2 and 16 (inclusive).

       welcome script
              Run  the  executable  or  shell command specified by script 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.

       xonxoff
              Use software flow control (i.e. XON/XOFF) to control the flow of data on the serial port.

OPTIONS FILES
       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.ttyname (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.ttyname file is read.)  In forming the name of  the  options.ttyname  file,  the  initial
       /dev/ is removed from the terminal name, and any remaining / characters are replaced with dots.

       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 file or call options within an options file.

SECURITY
       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.  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.

       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 auth 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.

       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 file option.  Privileged  options  may
       be  used in /etc/ppp/options file or in an options file read using the call option.  If pppd is being
       run by the root user, privileged options can be used without restriction.

       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 call option, pppd uses full root privileges when opening the device.  Thus, by creating an appro-priate appropriate
       priate file under /etc/ppp/peers, the system administrator can allow users to establish a ppp connec-tion connection
       tion  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.

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  corre-spond correspond
       spond to the internet hostnames of the peers, but this is not essential.

       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.

       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.

       The default behaviour of pppd is to agree to authenticate if requested, and to not require  authenti-cation authentication
       cation 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.

       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).   Both  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.

       Each line in a secrets file contains one secret.  A given secret is specific to a particular combina-tion combination
       tion 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  speci-fied specified
       fied client may use when connecting to the specified server.

       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.

       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.

       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 speci-fied specified
       fied address is not acceptable.  An address may be followed by "/" and a  number  n,  to  indicate  a
       whole  subnet,  i.e. all addresses which have the same value in the most significant n 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.

       Thus a secrets file contains both secrets for use in authenticating other hosts, plus  secrets  which
       we  use  for  authenticating ourselves to 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 domain option is used.  This default can  be  overridden  with  the  name
       option, except when the usehostname option is used.

       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  user  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 remotename  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.

       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 papcrypt option is given, the first (unencrypted) comparison is
       omitted, for better security.

       Furthermore, if the login 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 login 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.

       Authentication  must  be satisfactorily completed before IPCP (or any other Network Control Protocol)
       can be started.  If the peer is required to authenticate itself, and fails to do so, pppd will termi-nated terminated
       nated  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.

       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 authentica-tion. authentication.
       tion.  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.

ROUTING
       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 gen-erally generally
       erally requires further modification to routing  tables  and/or  ARP  (Address  Resolution  Protocol)
       tables.   In most cases the defaultroute and/or proxyarp options are sufficient for this, but in some
       cases further intervention is required.  The /etc/ppp/ip-up script can be used for this.

       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 defaultroute option causes
       pppd to create such a default route when IPCP comes up, and delete it when the link is terminated.

       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 proxyarp option causes pppd
       to look for a network interface on the same subnet as the remote host (an interface supporting broad-cast broadcast
       cast  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.

       When  the  demand  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  connec-tions, connections,
       tions,  and  the use of demand dialing with peers that do dynamic IP address assignment is not recom-mended. recommended.
       mended.

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.

       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.

       In  circumstances  the  peer  may send no endpoint discriminator or a non-unique value.  The optional
       bundle option adds an extra string which is added to the peer's endpoint discriminator and  authenti-cated authenticated
       cated  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/pppd.tdb to match up links.

       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.   Currently, if the first pppd terminates (for example, because of a hangup or a received signal)
       the bundle is destroyed.

EXAMPLES
       The following examples assume that the /etc/ppp/options file contains the  auth  option  (as  in  the
       default /etc/ppp/options file in the ppp distribution).

       Probably  the most common use of pppd is to dial out to an ISP.  This can be done with a command such
       as

              pppd call isp

       where the /etc/ppp/peers/isp file is set up by the system administrator  to  contain  something  like
       this:

              ttyS0 19200 crtscts
              connect '/usr/sbin/chat -v -f /etc/ppp/chat-isp'
              noauth

       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:

              ABORT "NO CARRIER"
              ABORT "NO DIALTONE"
              ABORT "ERROR"
              ABORT "NO ANSWER"
              ABORT "BUSY"
              ABORT "Username/Password Incorrect"
              "" "at"
              OK "at&d0&c1"
              OK "atdt2468135"
              "name:" "^Umyuserid"
              "word:" "\qmypassword"
              "ispts" "\q^Uppp"
              "~-^Uppp-~"

       See the chat(8) man page for details of chat scripts.

       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

              pppd proxyarp

       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 or /etc/ppp/chap-secrets (depending on which  authentica-tion authentication
       tion  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" which 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:

              joespc    server    "joe's secret" joespc.my.net

       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.

       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 asyncmap a____.  If the path includes a telnet, you probably should  escape  ^]  as  well
       (asyncmap  2__a____).   If  the path includes an rlogin, you will need to use the escape ff 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.

DIAGNOSTICS
       Messages are sent to the syslog daemon using facility LOG_RAS.  (This can be overriden 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.

       The  debug  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 debug option also causes
       other debugging messages to be logged.

       Debugging can also be enabled or disabled by sending a SIGUSR1 signal to the pppd process.  This sig-nal signal
       nal acts as a toggle.

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:

       0      Pppd has detached, or otherwise the connection was successfully established and terminated  at
              the peer's request.

       1      An immediately fatal error of some kind occurred, such as an essential system call failing, or
              running out of virtual memory.

       2      An error was detected in processing the options given, such as two mutually exclusive  options
              being used.

       3      Pppd is not setuid-root and the invoking user is not root.

       4      The  kernel does not support PPP, for example, the PPP kernel driver is not included or cannot
              be loaded.

       5      Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP signal.

       6      The serial port could not be locked.

       7      The serial port could not be opened.

       8      The connect script failed (returned a non-zero exit status).

       9      The command specified as the argument to the pty option could not be run.

       10     The PPP negotiation failed, that is, it didn't reach the point where at least one network pro-tocol protocol
              tocol (e.g. IP) was running.

       11     The peer system failed (or refused) to authenticate itself.

       12     The link was established successfully and terminated because it was idle.

       13     The  link  was  established  successfully  and  terminated  because the connect time limit was
              reached.

       14     Callback was negotiated and an incoming call should arrive shortly.

       15     The link was terminated because the peer is not responding to echo requests.

       16     The link was terminated by the modem hanging up.

       17     The PPP negotiation failed because serial loopback was detected.

       18     The init script failed (returned a non-zero exit status).

       19     We failed to authenticate ourselves to the peer.

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.  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:

       DEVICE The name of the serial tty device being used.

       IFNAME The name of the network interface being used.

       IPLOCAL
              The IP address for the local end of the link.  This is only set when IPCP has come up.

       IPREMOTE
              The IP address for the remote end of the link.  This is only set when IPCP has come up.

       PEERNAME
              The authenticated name of the peer.  This is only set if the peer authenticates itself.

       SPEED  The baud rate of the tty device.

       ORIG_UID
              The real user-id of the user who invoked pppd.

       PPPLOGNAME
              The username of the real user-id that invoked pppd. This is always set.

       For  the  ip-down and auth-down scripts, pppd also sets the following variables giving statistics for
       the connection:

       CONNECT_TIME
              The number of seconds from when the PPP negotiation started until the  connection  was  termi-nated. terminated.
              nated.

       BYTES_SENT
              The number of bytes sent (at the level of the serial port) during the connection.

       BYTES_RCVD
              The number of bytes received (at the level of the serial port) during the connection.

       LINKNAME
              The logical name of the link, set with the linkname option.

       DNS1   If  the  peer  supplies  DNS  server  addresses,  this variable is set to the first DNS server
              address supplied.

       DNS2   If the peer supplies DNS server addresses, this variable is  set  to  the  second  DNS  server
              address supplied.

       Pppd invokes the following scripts, if they exist.  It is not an error if they don't exist.

       /etc/ppp/auth-up
              A  program  or  script  which  is  executed after the remote system successfully authenticates
              itself.  It is executed with the parameters

              interface-name peer-name user-name tty-device speed

              Note that this script is not executed if the peer doesn't  authenticate  itself,  for  example
              when the noauth option is used.

       /etc/ppp/auth-down
              A  program or script which is executed when the link goes down, if /etc/ppp/auth-up was previ-ously previously
              ously executed.  It is executed in the same manner with the same parameters as  /etc/ppp/auth-up. /etc/ppp/authup.
              up.

       /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

              interface-name tty-device speed local-IP-address remote-IP-address ipparam

       /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
              script.  It is invoked in the same manner and with the same parameters as the ip-up script.

       /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

              interface-name tty-device speed local-link-local-address remote-link-local-address ipparam

       /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.

       /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

              interface-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 remote-IPXrouter-name
              router-name ipparam pppd-pid

              The local-IPX-routing-protocol and remote-IPX-routing-protocol field may be one of the follow-ing: following:
              ing:

              NONE      to indicate that there is no routing protocol
              RIP       to indicate that RIP/SAP should be used
              NLSP      to indicate that Novell NLSP should be used
              RIP NLSP  to indicate that both RIP/SAP and NLSP should be used

       /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.

FILES
       /var/run/pppn.pid (BSD or Linux), /etc/ppp/pppn.pid (others)
              Process-ID for pppd process on ppp interface unit n.

       /var/run/ppp-name.pid (BSD or Linux),
              /etc/ppp/ppp-name.pid (others) Process-ID for pppd process for  logical  link  name  (see  the
              linkname option).

       /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.

       /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.

       /etc/ppp/options
              System default options for pppd, read before user default options or command-line options.

       ~/.ppprc
              User default options, read before /etc/ppp/options.ttyname.

       /etc/ppp/options.ttyname
              System  default  options  for the serial port being used, read after ~/.ppprc.  In forming the
              ttyname 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.

       /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 authenti-cate, authenticate,
              cate, but only to certain trusted peers.

SEE ALSO
       RFC1144
              Jacobson, V.  Compressing TCP/IP headers for low-speed serial links.  February 1990.

       RFC1321
              Rivest, R.  The MD5 Message-Digest Algorithm.  April 1992.

       RFC1332
              McGregor, G.  PPP Internet Protocol Control Protocol (IPCP).  May 1992.

       RFC1334
              Lloyd, B.; Simpson, W.A.  PPP authentication protocols.  October 1992.

       RFC1661
              Simpson, W.A.  The Point-to-Point Protocol (PPP).  July 1994.

       RFC1662
              Simpson, W.A.  PPP in HDLC-like Framing.  July 1994.

       RFC2284
              Blunk, L.; Vollbrecht, J., PPP Extensible Authentication Protocol (EAP).  March 1998.

       RFC2472
              Haskin, D.  IP Version 6 over PPP December 1998.

NOTES
       Some limited degree of control can be exercised over a running pppd process by sending  it  a  signal
       from the list below.

       SIGINT, SIGTERM
              These  signals  cause  pppd  to terminate the link (by closing LCP), restore the serial device
              settings, and exit.

       SIGHUP This signal causes pppd to terminate the link, restore the serial device settings,  and  close
              the  serial  device.   If  the  persist  or demand 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.

       SIGUSR1
              This signal toggles the state of the debug option.

       SIGUSR2
              This signal causes pppd to renegotiate compression.  This can be useful to re-enable  compres-sion compression
              sion after it has been disabled as a result of a fatal decompression error.  (Fatal decompres-sion decompression
              sion errors generally indicate a bug in one or other implementation.)


AUTHORS
       Paul Mackerras (Paul.Mackerras@samba.org), based on earlier work by Drew Perkins, Brad Clements, Karl
       Fox, Greg Christy, and Brad Parker.



                                                                                                     PPPD(8)

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