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PPTP(8) 		     System Manager's Manual			 PPTP(8)

NAME
     pptp - PPTP driver

SYNOPSIS
     pptp <pptp-server-IP> <pptp-options> [ppp-options] ...

DESCRIPTION
     pptp  establishes	the client side of a Virtual Private Network (VPN) using
     the Point-to-Point Tunneling Protocol (PPTP).  Use this program to  connect
     to  an  employer's  PPTP  based  VPN,  or to certain cable and ADSL service
     providers.

     By default, pptp establishes the PPTP call to the	PPTP  server,  and  then
     starts  an instance of pppd to manage the data transfer.  However, pptp can
     also be run as a connection manager within pppd.

OPTIONS
     The first non-option argument on the pptp command line  must  be  the  host
     name or IP address of the PPTP server.

     All  long options (starting with "--") are interpreted as pptp options, and
     a fatal error occurs if an unrecognised option is used.

     All command-line arguments which do not start with "-" are  interpreted  as
     ppp options, and passed as is to pppd unless --nolaunchpppd is given.

     --phone <number>
	    Pass <number> to remote host as phone number

     --nolaunchpppd
	    Do	not  launch  pppd  but use stdin as the network connection.  Use
	    this flag when including pptp as a pppd connection process using the
	    pty option.  See EXAMPLES.

     --quirks <quirk>
	    Work around a buggy PPTP implementation, adopts  special  case  han-
	    dling for particular PPTP servers and ADSL modems.	Currently recog-
	    nised values are BEZEQ_ISRAEL only

     --debug
	    Run in foreground (for debugging with gdb)

     --sync
	    Enable Synchronous HDLC (pppd must use it too)

     --timeout <secs>
	    Time to wait for reordered packets (0.01 to 10 secs)

     --nobuffer
	    Completely	disables  buffering  and  reordering  of  packets.   Any
	    --timeout specified will be ignored.

     --idle-wait <secs>
	    Time to wait before sending a control connection echo request.   The
	    RFC2637 default is 60 seconds.

     --max-echo-wait <secs>
	    Time  to  wait  for an echo reply before closing the control connec-
	    tion.  The RFC2637 default is 60 seconds.

     --logstring <name>
	    Use <name> instead of 'anon' in syslog messages

     --localbind <addr>
	    Bind to specified IP address instead of wildcard

     --rtmark <n>
	    Use specified policy routing mark for all packets.	This causes both
	    the TCP control connection's packets as well as the GRE  packets  to
	    bear  the  given  policy  routing / netfilter mark. This can be used
	    with ip rule (from iproute2) to use a separate routing table for the
	    pptp client.

	    (requires root privileges or the CAP_NET_ADMIN capability.)

     --nohostroute
	    Do not configure a host route  pointing  towards  the  PPTP  server.
	    (cf. ROUTING below)

     --loglevel <level>
	    Sets the debugging level (0=low, 1=default, 2=high)

     --test-type <n>
	    Enable  packet  reordering	tests  that  damage the integrity of the
	    packet stream to the server.  Use this only  when  testing	servers.
	    Zero  is the default, and means that packets are sent in the correct
	    order.  A value of one (1) causes a single swap between two packets,
	    such that the sequence numbers might be 1 2 3 4 6 5 7 8 9.	A  value
	    of two (2) causes ten packets to be buffered, then sent out of order
	    but  ascending, such that the sequence numbers might be 1 2 3 4 16 6
	    7 8 9 10 11 12 13 14 15 17 18 19 20.  A value of  three  (3)  causes
	    ten  packets  to  be  buffered, then sent in the reverse order, like
	    this; 1 2 3 4 16 15 14 13 12 11 10 9 8 7 6 5 17 18 19 20.

     --test-rate <n>
	    Sets the number of packets to pass before causing a reordering test.
	    Default is 100.  Has no effect if test-type is zero.  The result  of
	    test types 2 and 3 are undefined if this value is less than ten.

ROUTING
     When  PPTP is used in conjunction with a default route on top of the tunnel
     (or just any route encompassing the PPTP server), the mechanics of  routing
     would  cause the PPTP packets themselves to be routed over the tunnel. This
     would result in an encapsulation loop, destroying connectivity.

     pptp by default works around this by looking up the route towards the  PPTP
     server  at startup and configures a host route with that data.  This essen-
     tially "freezes" routing for PPTP packets	at  the  startup  configuration.
     This  behaviour  can be disabled with --nohostroute if undesired (like when
     using --rtmark to implement policy routing).

     NB: the route added by pptp is currently not deleted at exit!

QUIRKS
     BEZEQ_ISRAEL
	    modifies packets to interoperate with  Orckit  ADSL  modems  on  the
	    BEZEQ network in Israel.

EXAMPLES
     Connection to a Microsoft Windows VPN Server

     pppd  noauth  nobsdcomp  nodeflate require-mppe-128 name domain\\\\username
     remotename PPTP pty "pptp 10.0.0.5 --nolaunchpppd"

     Note that the chap-secrets file used by pppd must include an entry for  do-
     main\\username

STATISTICS
     The  pptp	process collects statistics when sending and receiving GRE pack-
     ets. They are intended to be useful for debugging poor PPTP performance and
     for general monitoring of link quality. The statistics are cumulative since
     the pptp process was started.

     The statistics can be viewed by sending a SIGUSR1 signal to the "GRE-to-PPP
     Gateway" process, which will cause it to dump them to the system  logs  (at
     the  LOG_NOTICE  level). A better way to present the statistics to applica-
     tions is being sought (e.g. SNMP?).

     The following statistics are collected at the time of writing (April 2003):

     rx accepted
	    the number of GRE packets successfully passed to PPP

     rx lost
	    the number of packets never received, and presumed lost in the  net-
	    work

     rx under win
	    the number of packets which were duplicates or had old sequence num-
	    bers  (this  might	be caused by a packet-reordering network if your
	    reordering timeout is set too low)

     rx over win
	    the number of packets which were too far ahead in the sequence to be
	    reordered (might be caused by loss of more than  300  packets  in  a
	    row)

     rx buffered
	    the  number  of  packets  which were slightly ahead of sequence, and
	    were either buffered for reordering, or if	buffering  is  disabled,
	    accepted  immediately  (resulting  in the intermediate packets being
	    discarded).

     rx OS errors
	    the number of times where the operating  system  reported  an  error
	    when we tried to read a packet

     rx truncated
	    the  number of times we received a packet which was shorter than the
	    length implied by the GRE header

     rx invalid
	    the number of times we received a packet which had invalid or unsup-
	    ported flags set in the header, wrong version, or wrong protocol.

     rx acks
	    the number of pure acknowledgements  received  (without  data).  Too
	    many  of  these  will waste bandwidth, and might be solved by tuning
	    the remote host.

     tx sent
	    the number of GRE packets sent with data

     tx failed
	    the number of packets we tried to send, but the OS reported an error

     tx short
	    the number of times the OS would not let us write a complete packet

     tx acks
	    the number of times we sent a pure ack, without data

     tx oversize
	    the number of times we couldn't send a packet because  it  was  over
	    PACKET_MAX bytes long

     round trip
	    the estimated round-trip time in milliseconds

SEE ALSO
     pppd(8)

     Documentation in /usr/share/doc/pptp

AUTHOR
     This  manual  page was written by James Cameron <james.cameron@hp.com> from
     text contributed by  Thomas  Quinot  <thomas@debian.org>,	for  the  Debian
     GNU/Linux	system.  The description of the available statistics was written
     by Chris Wilson <chris@netservers.co.uk>. Updates for the Debian  distribu-
     tion by Ola Lundqvist <opal@debian.org>.

									 PPTP(8)

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