1PPTP(8) System Manager's Manual PPTP(8)
2
6 pptp - PPTP driver
7
9 pptp <pptp-server-IP> <pptp-options> [ppp-options] ...
10
12 pptp establishes the client side of a Virtual Private Network (VPN)
13 using the Point-to-Point Tunneling Protocol (PPTP). Use this program
14 to connect to an employer's PPTP based VPN, or to certain cable and
15 ADSL service providers.
16 By default, pptp establishes the PPTP call to the PPTP server, and then
18 starts an instance of pppd to manage the data transfer. However, pptp
19 can also be run as a connection manager within pppd.
20
22 The first non-option argument on the pptp command line must be the host
23 name or IP address of the PPTP server.
24 All long options (starting with "--") are interpreted as pptp options,
26 and a fatal error occurs if an unrecognised option is used.
27 All command-line arguments which do not start with "-" are interpreted
29 as ppp options, and passed as is to pppd unless --nolaunchpppd is
30 given.
31 --phone <number>
33 Pass <number> to remote host as phone number
34 --nolaunchpppd
36 Do not launch pppd but use stdin as the network connection. Use
37 this flag when including pptp as a pppd connection process using
38 the pty option. See EXAMPLES.
39 --quirks <quirk>
41 Work around a buggy PPTP implementation, adopts special case
42 handling for particular PPTP servers and ADSL modems. Currently
43 recognised values are BEZEQ_ISRAEL only
44 --debug
46 Run in foreground (for debugging with gdb)
47 --sync Enable Synchronous HDLC (pppd must use it too)
49 --timeout <secs>
51 Time to wait for reordered packets (0.01 to 10 secs)
52 --nobuffer
54 Completely disables buffering and reordering of packets. Any
55 --timeout specified will be ignored.
56 --idle-wait <secs>
58 Time to wait before sending a control connection echo request.
59 The RFC2637 default is 60 seconds.
60 --max-echo-wait <secs>
62 Time to wait for an echo reply before closing the control con‐
63 nection. The RFC2637 default is 60 seconds.
64 --logstring <name>
66 Use <name> instead of 'anon' in syslog messages
67 --localbind <addr>
69 Bind to specified IP address instead of wildcard
70 --rtmark <n>
72 Use specified policy routing mark for all packets. This causes
73 both the TCP control connection's packets as well as the GRE
74 packets to bear the given policy routing / netfilter mark. This
75 can be used with ip rule (from iproute2) to use a separate rout‐
76 ing table for the pptp client.
77 (requires root privileges or the CAP_NET_ADMIN capability.)
79 --nohostroute
81 Do not configure a host route pointing towards the PPTP server.
82 (cf. ROUTING below)
83 --loglevel <level>
86 Sets the debugging level (0=low, 1=default, 2=high)
87 --test-type <n>
90 Enable packet reordering tests that damage the integrity of the
91 packet stream to the server. Use this only when testing
92 servers. Zero is the default, and means that packets are sent
93 in the correct order. A value of one (1) causes a single swap
94 between two packets, such that the sequence numbers might be 1 2
95 3 4 6 5 7 8 9. A value of two (2) causes ten packets to be
96 buffered, then sent out of order but ascending, such that the
97 sequence numbers might be 1 2 3 4 16 6 7 8 9 10 11 12 13 14 15
98 17 18 19 20. A value of three (3) causes ten packets to be
99 buffered, then sent in the reverse order, like this; 1 2 3 4 16
100 15 14 13 12 11 10 9 8 7 6 5 17 18 19 20.
101 --test-rate <n>
104 Sets the number of packets to pass before causing a reordering
105 test. Default is 100. Has no effect if test-type is zero. The
106 result of test types 2 and 3 are undefined if this value is less
107 than ten.
108 --missing-window <n>
111 Enable 'missing window' validation and set packet tolerance
112 (300=default, 6000=recommended).
113 --version
116 Display version.
117
121 When PPTP is used in conjunction with a default route on top of the
122 tunnel (or just any route encompassing the PPTP server), the mechanics
123 of routing would cause the PPTP packets themselves to be routed over
124 the tunnel. This would result in an encapsulation loop, destroying con‐
125 nectivity.
126 pptp by default works around this by looking up the route towards the
128 PPTP server at startup and configures a host route with that data.
129 This essentially "freezes" routing for PPTP packets at the startup con‐
130 figuration. This behaviour can be disabled with --nohostroute if unde‐
131 sired (like when using --rtmark to implement policy routing).
132 NB: the route added by pptp is currently not deleted at exit!
134
137 BEZEQ_ISRAEL
138 modifies packets to interoperate with Orckit ADSL modems on the
139 BEZEQ network in Israel.
140
143 Connection to a Microsoft Windows VPN Server
144 pppd noauth nobsdcomp nodeflate require-mppe-128 name domain\\\\user‐
146 name remotename PPTP pty "pptp 10.0.0.5 --nolaunchpppd"
147 Note that the chap-secrets file used by pppd must include an entry for
149 domain\\username
150
153 The pptp process collects statistics when sending and receiving GRE
154 packets. They are intended to be useful for debugging poor PPTP perfor‐
155 mance and for general monitoring of link quality. The statistics are
156 cumulative since the pptp process was started.
157 The statistics can be viewed by sending a SIGUSR1 signal to the "GRE-
159 to-PPP Gateway" process, which will cause it to dump them to the system
160 logs (at the LOG_NOTICE level). A better way to present the statistics
161 to applications is being sought (e.g. SNMP?).
162 The following statistics are collected at the time of writing (April
164 2003):
165 rx accepted
167 the number of GRE packets successfully passed to PPP
168 rx lost
170 the number of packets never received, and presumed lost in the
171 network
172 rx under win
174 the number of packets which were duplicates or had old sequence
175 numbers (this might be caused by a packet-reordering network if
176 your reordering timeout is set too low)
177 rx over win
179 the number of packets which were too far ahead in the sequence
180 to be reordered (might be caused by loss of more than 300 pack‐
181 ets in a row)
182 rx buffered
184 the number of packets which were slightly ahead of sequence, and
185 were either buffered for reordering, or if buffering is dis‐
186 abled, accepted immediately (resulting in the intermediate pack‐
187 ets being discarded).
188 rx OS errors
190 the number of times where the operating system reported an error
191 when we tried to read a packet
192 rx truncated
194 the number of times we received a packet which was shorter than
195 the length implied by the GRE header
196 rx invalid
198 the number of times we received a packet which had invalid or
199 unsupported flags set in the header, wrong version, or wrong
200 protocol.
201 rx acks
203 the number of pure acknowledgements received (without data). Too
204 many of these will waste bandwidth, and might be solved by tun‐
205 ing the remote host.
206 tx sent
208 the number of GRE packets sent with data
209 tx failed
211 the number of packets we tried to send, but the OS reported an
212 error
213 tx short
215 the number of times the OS would not let us write a complete
216 packet
217 tx acks
219 the number of times we sent a pure ack, without data
220 tx oversize
222 the number of times we couldn't send a packet because it was
223 over PACKET_MAX bytes long
224 round trip
226 the estimated round-trip time in milliseconds
227
230 pppd(8)
231 Documentation in /usr/share/doc/pptp
233
235 This manual page was written by James Cameron <james.cameron@hp.com>
236 from text contributed by Thomas Quinot <thomas@debian.org>, for the
237 Debian GNU/Linux system. The description of the available statistics
238 was written by Chris Wilson <chris@netservers.co.uk>. Updates for the
239 Debian distribution by Ola Lundqvist <opal@debian.org>.
240 PPTP(8)