Content-type: text/html Manpage of PPTP

PPTP

Section: Maintenance Commands (8)
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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 argument on the pptp command line must be the host name or IP address of the PPTP server. Remaining arguments are checked for pptp options, and the arguments from the first unrecognised option onward are passed as is to pppd unless --nolaunchpppd is given.

--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.
--phone number: specifies the telephone number to place in the outgoing PPTP call request packet.
--localbind address: optional binding to a particular local IP address on a multi-homed host.
--quirks name: adopts special case handling for particular PPTP servers and ADSL modems.

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

pppdnoauthnobsdcompnodeflatemppe-40mppe-128 mppe-stateless name domain\\\\username remotename PPTP require-chapms-v2 pty "pptp 10.0.0.5 --nolaunchpppd"

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

STATISTICS

The pptp process collects statistics when sending and receiving GRE packets. 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 applications 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 network
rx under win: the number of packets which were duplicates or had old sequence numbers (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 buffered for reordering
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 unsupported 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

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>.

This document was created by man2html, using the manual pages.
Time: 14:02:59 GMT, November 18, 2003