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pppd



SYNOPSIS

       pppd [ tty_name ] [ speed ] [ options ]


DESCRIPTION

       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.

       The encapsulation scheme is provided by driver code in the
       kernel.  PPPD provides the basic LCP, authentication  sup­
       port,  and  an  NCP  for  establishing and configuring the
       Internet Protocol (IP) (called the  IP  Control  Protocol,
       IPCP).

       This  version  includes  support for multilink operations,
       Microsoft specific CHAP authentication  algorithms  (known
       as  CHAP-MS-V1  and CHAP-MS-V2) and transparent encryption
       (Microsoft Point-to-Point Encryption, MPPE) also.


FREQUENTLY USED OPTIONS

       <tty_name>
              Communicate over  the  named  device.   The  string
              "/dev/"  is  prepended  if necessary.  If no device
              name is given, or if the name of the terminal  con­
              nected  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.

       <speed>
              Set  the  baud  rate to <speed> (a decimal number).
              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.

       asyncmap <map>
              Set the async character map  to  <map>.   This  map
              describes  which  control characters cannot be suc­
              cessfully received over the serial line.  Pppd will
              ask  the  peer to send these characters as a 2-byte
              escape sequence.  The argument is a 32 bit hex num­
              ber  with  each  bit  representing  a  character to
              escape.  Bit 0 (00000001) represents the  character
              0x00;  bit  31  (80000000) represents the character
              0x1f or  ^_.   If  multiple  asyncmap  options  are
              given,   the  values  are  ORed  together.   If  no
              asyncmap option is given, no  async  character  map
              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.

       callback phone
              Request client to call back to specified phone num­
              ber.

       nocallback
              Don't argee to use callback negotiation.

       +callback
              Request server to negotiate callback and log  nego­
              tiated results.

       connect script
              Use  the  executable  or shell command specified by
              script to set up  the  serial  line.   This  script
              would typically use the chat(8) program to dial the
              modem and start the remote ppp  session.   A  value
              for  this option from a privileged source cannot be
              overridden by a non-privileged user.

       crtscts
              Use hardware flow control (i.e. RTS/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 con­
              trol 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 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 negotia­
              tion is  successfully  completed.   This  entry  is
              removed  when  the  PPP connection is broken.  This
              option is privileged if the  nodefaultroute  option
              has been specified.

       replacedefaultroute
              This  option  is a flag to the defaultroute option.
              If defaultroute is set and this flag is  also  set,

       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  charac­
              ters 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
              Run  the  executable  or shell command specified by
              script to initialize the serial line.  This  script
              would  typically use the chat(8) program to config­
              ure the modem to enable auto answer.  A  value  for
              this  option  from  a  privileged  source cannot be
              overridden by a non-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 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).  (Note that for IPv6 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 net­
              working  code  send  data packets of no more than n
              bytes through the  PPP  network  interface.   (Note
              that for IPv6 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
              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_iden­
       tifier>
              Set  the local and/or remote 64-bit interface iden­
              tifier. Either one may be omitted.  The  identifier
              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-dialling  mode.   This  option  is useful in
              conjunction with the idle option if there are pack­
              ets  being sent or received regularly over the link
              (for example, routing  information  packets)  which
              would  otherwise prevent the link from ever appear­
              ing to be idle.  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. This option is cur­
              rently  only  available  under NetBSD or Linux, and
              then only if both the kernel and pppd were compiled
              with PPP_FILTER defined.

       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).

       bsdcomp nr,nt
              Request  that  the  peer  compress  packets that it
              sends, using the BSD-Compress scheme, with a  maxi­
              mum  code  size  of  nr bits, and agree to compress
              packets sent to the peer with a maximum  code  size
              hardware flow control setting for the  serial  port
              is left unchanged.  Some serial ports (such as Mac­
              intosh 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 transmis­
              sions to n (default 10).

       chap-restart n
              Set the CHAP restart interval (retransmission time­
              out 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 negotia­
              tion  by sending its first LCP packet.  The default
              value is 1000 (1 second).  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/sys­
              log.conf appropriately (see syslog.conf(5)).

       default-asyncmap
              Disable  asyncmap  negotiation, forcing all control
              characters to be escaped for both the transmit  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
              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 ini­
              tially configure the interface and enable it for IP
              traffic without connecting to the peer.  When traf­
              fic 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  nopersist
              option after the demand option.  The idle and hold­
              off options are also useful in conjuction with  the
              demand option.

       domain d
              Append the domain name d to the local host name for
              authentication purposes.  For example, if  gethost­
              name()  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 initiat­
              ing  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 negotiation 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 multi­
              cast 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

       holdoff n
              Specifies how many seconds to wait before re-initi­
              ating  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  activ­
              ity filter also count as the link being idle.

       ip     Enable  IPCP  and  IP protocols. You can disable IP
              negotiation if you  want  to  use  other  protocols
              only.

       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
              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 time­
              out) 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-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 sup­
              port.

       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  network  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  speci­
              fied  as the only instance of ipx-routing. The val­
              ues may be 0 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 speci­
              fied,  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 speci­
              fied in the ipx-network option. If a network number
              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 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  debug­
              ging  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.

       ktune  Enables  pppd to alter kernel settings as appropri­
              ate.  Under Linux, pppd will enable  IP  forwarding
              (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 connection.   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 connec­
              tion has been broken (e.g., the modem has hung  up)
              in situations where no hardware modem control lines
              are available.

       lcp-echo-interval n
              If this option is given,  pppd  will  send  an  LCP

       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 time­
              out) 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  pro­
              cess  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  (Car­
              rier  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 logfile 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 sys­
              tem 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
              rently only available under Linux.

       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).

       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 speci­
              fies 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 dns-addr.)

       ms-wins <addr>
              If pppd is acting as a server for Microsoft Windows
              or "Samba" clients, this option allows pppd to sup­
              ply  one  or  two  WINS (Windows Internet Name Ser­
              vices) 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 sys­
              tem and the peer.  If there is an  existing  bundle
              to  the peer, pppd will join this link to that bun­
              dle, otherwise pppd will create a new bundle.   See
              the  MULTILINK  section below.  This option is cur­
              rently 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
              system  which  are  on the same network.  (Note: on
              some    platforms,    pppd    will    always    use
              255.255.255.255  for  the  netmask,  if that is the
              only appropriate value for a point-to-point  inter­
              face.)

       noaccomp
              Disable  Address/Control compression in both direc­
              tions (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) negotia­
              tion.  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 admin­
              istrator  who wishes to prevent users from adding a
              default route with pppd can do so by  placing  this
              option in the /etc/ppp/options file.

       noreplacedefaultroute
              Disable  the replacedefaultroute option. The system
              administrator who  wishes  to  prevent  users  from
              replacing  a  default  route 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.

              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 nego­
              tiation.

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

       nolog  Do not send log messages to a file or file descrip­
              tor.   This  option  cancels  the logfd and logfile
              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.

       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
              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  master  and its standard input and
              output.  Thus pppd will transmit characters on  its
              standard output and receive characters on its stan­
              dard 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  compres­
              sion  in  both  the transmit and the receive direc­
              tion.

       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 iden­
              tity of the  peer  are  encrypted,  and  thus  pppd
              should  not accept a password which, before encryp­
              tion,  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  time­
              out) 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 pack­
              packets using the inbound and outbound  qualifiers.
              This  option  is  currently  only  available  under
              NetBSD or Linux, and then only if both  the  kernel
              and pppd were compiled with PPP_FILTER defined.

       persist
              Do  not  exit  after  a  connection  is terminated;
              instead try to reopen the connection.

       plugin filename
              Load the shared library object file filename  as  a
              plugin.  This is a privileged option.

       predictor1
              Request that the peer compress frames that it sends
              using Predictor-1 compression, and  agree  to  com­
              press   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 privi­
              leged options.  This is a privileged  option.   Use
              of this option requires care as there is no guaran­
              tee that members of group-name cannot use  pppd  to
              become  root themselves.  Consider it equivalent to
              putting the members of group-name in  the  kmem  or
              disk group.

       proxyarp
              Add  an entry to this system's ARP [Address Resolu­
              tion 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
              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.

       refuse-chap
              With  this option, pppd will not agree to authenti­
              cate itself to the peer using any CHAP protocol.

       refuse-chap-md5
              With this option, pppd will not agree to  authenti­
              cate itself to the peer using standard MD5 CHAP.

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

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

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

       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  pack­
              ets  to  initiate  a  connection  until a valid LCP
              packet is received from the peer (as for the  `pas­
              sive' 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.

       updetach
              With  this  option,  pppd will detach from its con­
              trolling terminal once it has  successfully  estab­
              lished  the  ppp connection (to the point where the
              first network control protocol, usually the IP con­
              trol protocol, has come up).

              plied 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 con­
              trol the flow of data on the serial port.


MICROSOFT SPECIFIC EXTENSIONS

       This version  of  PPPD  supports  some  Microsoft-specific
       extensions  such as non-standard CHAP algorithms (known as
       CHAP-MS-V1 and CHAP-MS-V2) and transparent  encryption  of
       all sending and receiving traffic.

       Those  options  allows  to  configure  PPPD  to  work with
       Microsoft extensions of standard PPP protocol.

       require-chapms
              Require the peer to authenticate itself using  CHAP
              [Challenge   Handshake   Authentication   Protocol]
              authentication with Microsoft extensions [known  as
              CHAP-MS-V1].

       require-chapms-v2
              Require  the peer to authenticate itself using CHAP
              authentication with Microsoft extensions [known  as
              CHAP-MS-V2].

       refuse-chapms
              With  this option, pppd will not agree to authenti­
              cate itself to the peer using CHAP-MS-V1.

       refuse-chapms-v2
              With this option, pppd will not agree to  authenti­
              cate itself to the peer using CHAP-MS-V2.

       mppe-40

       mppe-stateless
              This option negotiates stateless mode for Microsoft
              Point-to-Point Encryption (MPPE), which changes the
              encryption  keys  on every packet. The default mode
              is stateful (non-stateless, or single key).


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  ini­
       tial  /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,  delim­
       ited  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 pro­
       vided to legitimate users without fear of compromising the
       security  of the server or the network it's on.  This con­
       trol  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 unauthenti­
       cated 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.

       privileged source, that is, /etc/ppp/options or an options
       file read using the call option, pppd uses full root priv­
       ileges  when  opening  the  device.   Thus, by creating an
       appropriate file under /etc/ppp/peers, the system adminis­
       trator 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.


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 authentica­
       tion correspond to the internet hostnames  of  the  peers,
       but this is not essential.

       At  present,  pppd  supports two authentication protocols:
       the Password Authentication Protocol (PAP) and  the  Chal­
       lenge   Handshake  Authentication  Protocol  (CHAP).   PAP
       involves the client sending its name and a cleartext pass­
       word  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  authentica­
       tion 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 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.

       Pppd stores secrets for use in authentication  in  secrets
       files (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets

       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 spe­
       cial characters quoted or escaped.  Note that case is sig­
       nificant 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 specified 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 authen­
       ticating 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 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

       Furthermore, if the login option was specified, the  user­
       name  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 cer­
       tain 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 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.

       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 authenti­
       cate 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  generally requires further modification to rout­
       ing  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 exam­
       the peer is an ISP that uses dynamic  IP  address  assign­
       ment),  pppd  has  to change the interface IP addresses to
       the negotiated addresses.  This may disrupt existing  con­
       nections,  and  the use of demand dialling with peers that
       do dynamic IP address assignment is not recommended.


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.  Cur­
       rently, 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 num­
       bers.  The endpoint discriminator sent to the peer by pppd
       can be set using the endpoint option.

       In circumstances the peer may send no endpoint discrimina­
       tor or a non-unique value.   The  optional  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 mul­
       tiple 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  bun­
       dle,  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 exam­
       ple,  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

              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 sim­
       plest  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 authentication method the  PPP  imple­
       mentation  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 exam­
       ple)  "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 use­
       ful to escape XON  (^Q)  and  XOFF  (^S),  using  asyncmap
       a0000.  If the path includes a telnet, you probably should
       escape ^]  as  well  (asyncmap  200a0000).   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;
       2, you need to use those options:

              auth
              +chap
              +chapms
              +chapms-v2

       To  make  possible to authentificate itself with Microsoft
       CHAP version 1 or 2, you need to add those options:

              +chapms
              +chapms-v2


DIAGNOSTICS

       (This can be overriden by recompiling pppd with the  macro
       LOG_PPP defined as the desired facility.)  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.

       The debug option causes the contents of all control  pack­
       ets  sent or received to be logged, that is, all LCP, PAP,
       CHAP or IPCP packets.  This can be useful if the PPP nego­
       tiation  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 signal 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  ter­
       minated.  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  run­
              ning 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
              option could not be run.

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

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

       12     The link was established  successfully  and  termi­
              nated because it was idle.

       13     The  link  was  established successfully and termi­
              nated 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 pro­
       cessing.  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  vari­
       ables 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 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 terminated.

       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.

       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 previously exe­
              cuted.  It is executed in the same manner with  the
              same parameters as /etc/ppp/auth-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
              ters

              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-pro­
              tocol  local-IPX-router-name remote-IPX-router-name
              ipparam pppd-pid

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

              NONE      to indicate that there is no routing pro­
              tocol
              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 param­
              eters as the ipx-up script.


FILES

       /var/run/pppn.pid  (BSD or Linux), /etc/ppp/pppn.pid (oth­
       ers)
              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/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 con­
              tain  privileged  options, even if pppd was invoked
              by a user other than root.  The system  administra­
              tor  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.


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  Proto­
              col (IPCP).  May 1992.

       RFC1334
              Lloyd, B.; Simpson, W.A.  PPP authentication proto­
              cols.  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.

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

              holdoff period).  Otherwise  pppd  will  exit.   If
              this  signal is received during the holdoff period,
              it causes pppd to end the  holdoff  period  immedi­
              ately.

       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 compression after
              it has been disabled as a result of a fatal  decom­
              pression error.  (Fatal decompression errors gener­
              ally indicate a bug in  one  or  other  implementa­
              tion.)


AUTHORS

       Paul  Mackerras  (Paul.Mackerras@cs.anu.edu.au),  based on
       earlier work by Drew Perkins,  Brad  Clements,  Karl  Fox,
       Greg Christy, and Brad Parker.

                                                          PPPD(8)
  
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