PPPOS2(1)                                               PPPOS2(1)


NAME
       ppp - Point to Point Protocol for OS/2 TCP/IP 2.0

SYNOPSIS
       ppp [ options ] [ com port ] [ speed ]

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 an OS/2 Ring 3
       driver and an interface to the TCP/IP  kernel.   PPP  pro-
       vides  the  basic  LCP, authentication support, and an NCP
       for establishing and  configuring  the  Internet  Protocol
       (IP) (called the IP Control Protocol, IPCP).

FREQUENTLY USED OPTIONS
       <com port>
              Communicate  over  the  named  com  device.   If no
              device name is given, ppp will use com1.

       <speed>
              Set the async port line speed to <speed>.

       asyncmap <map>
              Set the async character map  to  <map>.   This  map
              describes  which  control characters cannot be suc-
              cessfully received over the serial line.  ppp  will
              ask  the  peer to send these characters as a 2-byte
              "escape" sequence.  The argument is a  32  bit  hex
              number  with  each  bit representing a character to
              escape.  Bit 0 (00000001) represents the  character
              0x00;  bit  31  (80000000) represents the character
              0x1f or ^_.  The default asyncmap is 0.  If  multi-
              ple asyncmap options are given, the values are ORed
              together.

       auth   Require the  peer  to  authenticate  itself  before
              allowing network packets to be sent or received.

       connect <command>
              Use  the  executable  or shell command specified by
              <command> to set up the serial line.   This  script
              would  typically  use  the  "slattach" program or a
              REXX command file to dial the  modem  and  start  a
              remote ppp session.

       defaultroute
              Add  a  default route to the system routing tables,



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PPPOS2(1)                                               PPPOS2(1)


              using the peer as the gateway, when  IPCP  negotia-
              tion  is  successfully  completed.   This  entry is
              removed when the PPP connection is broken.

       file <filename>
              Read options from file <filename>  (the  format  is
              described below).

       help (-?)
              Display  ppp  usage information for the most common
              options.

       mru <n>
              Set the MRU [Maximum Receive Unit] value to <n> for
              negotiation.  ppp 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 interactive  links  (40
              bytes for TCP/IP header + 256 bytes of data).

       netmask <n>
              Set  the interface netmask to <n>, a 32 bit netmask
              in "decimal dot" notation (e.g. 255.255.255.0).

       passive
              Enables the "passive" option in the LCP.  With this
              option,  ppp will attempt to initiate a connection;
              if no reply is received from  the  peer,  ppp  will
              then  just  wait  passively  for a valid LCP packet
              from the peer (instead of exiting, as it does with-
              out this option).

       restart
              Restart  LCP  negotiation  after  link termination.
              This overrides the default behavior of  terminating
              the ppp driver after disconnect.

       rtscts Use hardware flow control (i.e. RTS/CTS) to control
              the flow of data on the serial port.

       silent With this option, ppp will not transmit LCP packets
              to  initiate  a connection until a valid LCP packet
              is received from the peer.

OTHER 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.  "150.203.23.247").   The  default
              local address is the first IP address of  the  sys-
              tem.   The remote address will be obtained from the
              peer if not specified in any option.  Thus, in sim-
              ple cases, this option is not required.



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PPPOS2(1)                                               PPPOS2(1)


       -all   Don't  request  or allow negotiation of any options
              for LCP and IPCP, use default values.

       -ac    Disable  Address/Control  compression   negotiation
              (use default, i.e.  disabled).

       -am    Disable  asyncmap  negotiation  (use  default, i.e.
              0xffffffff).

       -as <n>
              Same as asyncmap <n>

       -d     Increase debugging level.

       -ip    Disable IP address negotiation.  With this  option,
              the  remote  IP  address  must be specified with an
              option on the command line or in an options file.

       -mn    Disable  magic  number  negotiation.    With   this
              option, ppp cannot detect a looped-back line.

       -mru   Disable MRU [Maximum Receive Unit] negotiation (use
              default, i.e. 1500).

       -p     Same as the passive option.

       -pc    Disable protocol field compression negotiation (use
              default, i.e. disabled).

       +ua <p>
              Agree to authenticate using PAP [Password Authenti-
              cation Protocol] if requested by the peer, and  use
              the  data  in file <p> for the user and password to
              send to the peer. The file contains the remote user
              name, followed by a newline, followed by the remote
              password, followed by a newline.

       +pap   Require the peer to authenticate itself using  PAP.

       -pap   Don't agree to authenticate using PAP.

       +chap  Require  the peer to authenticate itself using CHAP
              [Cryptographic Handshake  Authentication  Protocol]
              authentication.

       -chap  Don't agree to authenticate using CHAP.

       -vj    Disable negotiation of Van Jacobson style IP header
              compression (use default, i.e. no compression).

       debug  Increase debugging level (same as -d ).

       domain <d>
              Append the domain name <d> to the local  host  name



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PPPOS2(1)                                               PPPOS2(1)


              for authentication purposes.  For example, if geth-
              ostname() returns the name foobar,  but  the  fully
              qualified  domain name is foobar.IBM.COM, you would
              use the domain option to set  the  domain  name  to
              IBM.COM.

       exit   Causes  the  ppp  driver  to terminate on detecting
              loss of the modem Data Carrier Detect (DCD) signal.

       idle <n>
              Set  the  amount of inactivity time (no IP traffic)
              until the ppp driver hangs up the connection.

       local  Don't use modem control lines.

       name <n>
              Set the name of the local system for authentication
              purposes to <n>.

       user <u>
              Set  the  user  name to use for authenticating this
              machine with the peer using PAP to <u>.

       usehostname
              Enforce the use of the hostname as the name of  the
              local system for authentication purposes (overrides
              the name option).

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

       proxyarp
              Add  an entry to this system's ARP [Address Resolu-
              tion Protocol] table with the  IP  address  of  the
              peer  and  the  Token-Ring/Ethernet address of this
              system.

       login  Use the system password database for authenticating
              the peer using PAP.

       secret <secret>
              Use  the secret <secret> for PAP and CHAP authenti-
              cation with the peer.

       lcp-restart <n>
              Set the LCP restart interval (retransmission  time-
              out) to <n> seconds (default 3).

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





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PPPOS2(1)                                               PPPOS2(1)


       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
              instead to <n> (default 10).

       ipcp-restart <n>
              Set the IPCP restart interval (retransmission time-
              out) to <n> seconds (default 5 seconds).

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

       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).

       pap-restart <n>
              Set the PAP restart interval (retransmission  time-
              out) to <n> seconds (default 5 seconds).

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

       chap-restart <n>
              Set the CHAP restart interval (retransmission time-
              out  for challenges) to <n> seconds (default 5 sec-
              onds).

       chap-max-challenge <n>
              Set the maximum number of CHAP challenge  transmis-
              sions to <n> (default 10).

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

OPTIONS FILES
       Options can be taken from files as  well  as  the  command
       line.   ppp  reads options from the files $ETC/ppp.cfg and
       $HOME/ppprc  before  looking  at  the  command  line.   An
       options  file  is parsed into a series of words, delimited
       by whitespace.  Whitespace can be included in  a  word  by
       enclosing  the word in quotes (").  A backslash (\) quotes



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PPPOS2(1)                                               PPPOS2(1)


       the following character.  A hash  (#)  starts  a  comment,
       which continues until the end of the line.

AUTHENTICATION
       The  PAP  and  CHAP secrets files can be setup to restrict
       the set of IP addresses which individual users may use.

       The default behaviour of ppp is to agree  to  authenticate
       if  requested,  and to not require authentication from the
       peer.  However, ppp will not agree to authenticate  itself
       with  a  particular  protocol  if  it has no secrets which
       could be used to do so.

       Authentication is based on  secrets,  which  are  selected
       from    secrets   files,   $ETC/pap.sct   for   PAP,   and
       $ETC/chap.sct for CHAP.  Both secrets files have the  same
       format,  and  both  can store secrets for several combina-
       tions of server (authenticating  peer)  and  client  (peer
       being  authenticated).  Note that ppp can be both a server
       and client, and that different protocols can  be  used  in
       the two directions if desired.

       A secrets file is parsed into words similar to the options
       file.  A secret is specified by a line containing at least
       3 words, in the order client, server, secret.  Any follow-
       ing words on the same line are  taken  to  be  a  list  of
       acceptable  IP  addresses  for  that client.  If there are
       only 3 words on the  line,  it  is  assumed  that  any  IP
       address is OK.  To disallow all IP addresses, use "-".  If
       the secret starts with an `@', what follows is assumed  to
       be  the  name  of a file from which to read the secret.  A
       "*" as the client or server name matches any  name  (wild-
       card).  When selecting a secret, ppp takes the best match,
       i.e. the match with the fewest wildcards.

       A secrets file contains both secrets for use in  authenti-
       cating  other  hosts,  plus  secrets which can be used for
       authenticating ourselves to others.  Which secret  to  use
       is  chosen  based  on  the  names  of the host (the `local
       name') and its peer (the `remote name').  The  local  name
       is set as follows:

       if the usehostname option is given,
          then  the  local  name  is the hostname of this machine
          (with the domain appended, if supplied)

       else if the name option is given,
          then use the argument of the first name option seen

       else if the local IP address is specified with a hostname,
          then use that name

       else  use the hostname of this machine (with the domain
          appended, if given)



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PPPOS2(1)                                               PPPOS2(1)


       When  authenticating  ourselves using PAP, there is also a
       `username' which is the local name by default, but can  be
       set with the user option or the +ua option.

       The remote name is set as follows:

       if the remotename option is given,
          then  use  the  argument  of the last remotename option
          seen

       else if the remote IP address is specified with a host-
          name,
          then use that host name

       else the remote name is the null string "".

       Secrets are selected from the PAP secrets file as follows:

       o For authenticating the peer, look for a secret with
         client ==
         username  specified in the PAP authenticate-request, and
         server == local name.

       o  For authenticating ourselves to the peer, look  for  a
         secret with
         client == our username, server == remote name.

       When authenticating the peer with  PAP,  a  secret  of  ""
       matches  any  password supplied by the peer.  If the pass-
       word doesn't match the secret, the password  is  encrypted
       using  crypt()  and checked against the secret again; thus
       secrets for authenticating  the  peer  can  be  stored  in
       encrypted  form.   If  the 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  cer-
       tain  users,  and to restrict the set of IP addresses that
       each user can use.

       Secrets are selected from the CHAP secrets  file  as  fol-
       lows:

       o  For  authenticating the peer, look for a secret with
         client == name
         specified  in  the  CHAP-Response message, and server ==
         local name.

       o  For authenticating ourselves to the peer, look  for  a
         secret with
         client == local name, and server ==  name  specified  in
         the CHAP-Challenge message.

       Authentication  must  be  satisfactorily  completed before
       IPCP (or  any  other  Network  Control  Protocol)  can  be



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PPPOS2(1)                                               PPPOS2(1)


       started.  If authentication fails, ppp 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.

ROUTING
       When IPCP negotiation is completed successfully, ppp  will
       inform  the  TCP/IP  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.   Communica-
       tion  with other machines generally requires further modi-
       fication to routing tables and/or ARP (Address  Resolution
       Protocol) tables.  In some cases this may be done automat-
       ically through the actions of command scripts, but in most
       cases some further intervention is required.

       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  ppp  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-
       ple  on  a  server machine connected to a LAN, in order to
       allow other hosts to communicate  with  the  remote  host.
       The  proxyarp  option  causes  ppp  to  look for a network
       interface on the same  subnet  as  the  remote  host,  (an
       interface  supporting  broadcast  and ARP, which is up and
       not a point-to-point or loopback  interface).   If  found,
       ppp  creates  a permanent, published ARP entry with the IP
       address of the remote host and the hardware address of the
       network interface found.

EXAMPLES
       In  the simplest case, you can connect the serial ports of
       two machines via a NULL modem cable and  issue  a  command
       like

              ppp com1 38400 passive

       to each machine.

       The  process  of logging in to a host machine and starting
       ppp can be automated by using the connect  option  to  run
       slattach or a REXX script, for example:

              ppp com1 38400 connect "slattach AT OK ATDT999-9999
              CONNECT login: foobar Password: password"

       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



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PPPOS2(1)                                               PPPOS2(1)


       useful  to  escape  XON (^Q) and XOFF (^S), using asyncmap
       a0000.  If the path includes a telnet, you probably should
       escape  ^]  as  well  (asyncmap  200a0000).   Don't use an
       rlogin in the path - many implementations are  not  trans-
       parent;  they  will remove the sequence [0xff, 0xff, 0x73,
       0x73, followed by any 8 bytes] from the stream.

DIAGNOSTICS
       Messages  are  logged  to  both  the   console   and   the
       $ETC/ppp<n>.log file.

FILES
       $ETC/ppp<n>.pid
              Process-ID for ppp process on ppp interface unit n.

       $ETC/pap.sct
              Usernames,  passwords  and  IP  addresses  for  PAP
              authentication.

       $ETC/chap.sct
              Names,  secrets and IP addresses for CHAP authenti-
              cation.

       $ETC/ppp.cfg
              System default options for ppp,  read  before  user
              default options or command-line options.

       $HOME/ppprc
              User  default  options,  read  before  command-line
              options.

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

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

       RFC1331
              Simpson, W.A.  Point-to-Point  Protocol  (PPP)  for
              the  transmission  of multi-protocol datagrams over
              point-to-point links.  1992 May.

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

       RFC1334
              Lloyd, B.; Simpson, W.A.  PPP authentication proto-
              cols.  1992 October.





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PPPOS2(1)                                               PPPOS2(1)


NOTES
       The following signals have the specified effect when  sent
       to the ppp process.

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

BUGS
       Usability issues, several to be resolved prior to GA.
