source: rtems/cpukit/pppd/pppd.8 @ 6ac6a5c8

5
Last change on this file since 6ac6a5c8 was 65c6425, checked in by Joel Sherrill <joel.sherrill@…>, on 05/03/12 at 17:24:46

Remove CVS Id Strings (manual edits after script)

These modifications were required by hand after running the script.
In some cases, the file names did not match patterns. In others,
the format of the file did not match any common patterns.

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1.\" manual page [] for pppd 2.3
2.\" SH section heading
3.\" SS subsection heading
4.\" LP paragraph
5.\" IP indented paragraph
6.\" TP hanging label
7.TH PPPD 8
8.SH NAME
9pppd \- Point to Point Protocol daemon
10.SH SYNOPSIS
11.B pppd
12[
13.I tty_name
14] [
15.I speed
16] [
17.I options
18]
19.SH DESCRIPTION
20.LP
21The Point-to-Point Protocol (PPP) provides a method for transmitting
22datagrams over serial point-to-point links.  PPP
23is composed of three parts: a method for encapsulating datagrams over
24serial links, an extensible Link Control Protocol (LCP), and
25a family of Network Control Protocols (NCP) for establishing
26and configuring different network-layer protocols.
27.LP
28The encapsulation scheme is provided by driver code in the kernel.
29Pppd provides the basic LCP, authentication support, and an NCP for
30establishing and configuring the Internet Protocol (IP) (called the IP
31Control Protocol, IPCP).
32.SH FREQUENTLY USED OPTIONS
33.TP
34.I <tty_name>
35Communicate over the named device.  The string "/dev/" is prepended if
36necessary.  If no device name is given, or if the name of the terminal
37connected to the standard input is given, pppd will use that terminal,
38and will not fork to put itself in the background.  A value for this
39option from a privileged source cannot be overridden by a
40non-privileged user.
41.TP
42.I <speed>
43Set the baud rate to <speed> (a decimal number).  On systems such as
444.4BSD and NetBSD, any speed can be specified.  Other systems
45(e.g. SunOS) allow only a limited set of speeds.
46.TP
47.B asyncmap \fI<map>
48Set the async character map to <map>.  This map describes which
49control characters cannot be successfully received over the serial
50line.  Pppd will ask the peer to send these characters as a 2-byte
51escape sequence.  The argument is a 32 bit hex number with each bit
52representing a character to escape.  Bit 0 (00000001) represents the
53character 0x00; bit 31 (80000000) represents the character 0x1f or ^_.
54If multiple \fIasyncmap\fR options are given, the values are ORed
55together.  If no \fIasyncmap\fR option is given, no async character
56map will be negotiated for the receive direction; the peer should then
57escape \fIall\fR control characters.  To escape transmitted
58characters, use the \fIescape\fR option.
59.TP
60.B auth
61Require the peer to authenticate itself before allowing network
62packets to be sent or received.  This option is the default if the
63system has a default route.  If neither this option nor the
64\fInoauth\fR option is specified, pppd will only allow the peer to use
65IP addresses to which the system does not already have a route.
66.TP
67.B call \fIname
68Read options from the file /etc/ppp/peers/\fIname\fR.  This file may
69contain privileged options, such as \fInoauth\fR, even if pppd
70is not being run by root.  The \fIname\fR string may not begin with /
71or include .. as a pathname component.  The format of the options file
72is described below.
73.TP
74.B connect \fIscript
75Use the executable or shell command specified by \fIscript\fR to set
76up the serial line.  This script would typically use the chat(8)
77program to dial the modem and start the remote ppp session.  A value
78for this option from a privileged source cannot be overridden by a
79non-privileged user.
80.TP
81.B crtscts
82Use hardware flow control (i.e. RTS/CTS) to control the flow of
83data on the serial port.  If neither the \fIcrtscts\fR, the
84\fInocrtscts\fR, the \fIcdtrcts\fR nor the \fInocdtrcts\fR option
85is given, the hardware flow control setting for the serial port is
86left unchanged.
87Some serial ports (such as Macintosh serial ports) lack a true
88RTS output. Such serial ports use this mode to implement
89unidirectional flow control. The serial port will
90suspend transmission when requested by the modem (via CTS)
91but will be unable to request the modem stop sending to the
92computer. This mode retains the ability to use DTR as
93a modem control line.
94.TP
95.B defaultroute
96Add a default route to the system routing tables, using the peer as
97the gateway, when IPCP negotiation is successfully completed.
98This entry is removed when the PPP connection is broken.  This option
99is privileged if the \fInodefaultroute\fR option has been specified.
100.TP
101.B disconnect \fIscript
102Run the executable or shell command specified by \fIscript\fR after
103pppd has terminated the link.  This script could, for example, issue
104commands to the modem to cause it to hang up if hardware modem control
105signals were not available.  The disconnect script is not run if the
106modem has already hung up.  A value for this option from a privileged
107source cannot be overridden by a non-privileged user.
108.TP
109.B escape \fIxx,yy,...
110Specifies that certain characters should be escaped on transmission
111(regardless of whether the peer requests them to be escaped with its
112async control character map).  The characters to be escaped are
113specified as a list of hex numbers separated by commas.  Note that
114almost any character can be specified for the \fIescape\fR option,
115unlike the \fIasyncmap\fR option which only allows control characters
116to be specified.  The characters which may not be escaped are those
117with hex values 0x20 - 0x3f or 0x5e.
118.TP
119.B file \fIname
120Read options from file \fIname\fR (the format is described below).
121The file must be readable by the user who has invoked pppd.
122.TP
123.B init \fIscript
124Run the executable or shell command specified by \fIscript\fR to
125initialize the serial line.  This script would typically use the
126chat(8) program to configure the modem to enable auto answer.  A value
127for this option from a privileged source cannot be overridden by a
128non-privileged user.
129.TP
130.B lock
131Specifies that pppd should create a UUCP-style lock file for the
132serial device to ensure exclusive access to the device.
133.TP
134.B mru \fIn
135Set the MRU [Maximum Receive Unit] value to \fIn\fR. Pppd
136will ask the peer to send packets of no more than \fIn\fR bytes.  The
137minimum MRU value is 128.  The default MRU value is 1500.  A value of
138296 is recommended for slow links (40 bytes for TCP/IP header + 256
139bytes of data).  (Note that for IPv6 MRU must be at least 1280)
140.TP
141.B mtu \fIn
142Set the MTU [Maximum Transmit Unit] value to \fIn\fR.  Unless the
143peer requests a smaller value via MRU negotiation, pppd will
144request that the kernel networking code send data packets of no more
145than \fIn\fR bytes through the PPP network interface.  (Note that for
146IPv6 MTU must be at least 1280)
147.TP
148.B passive
149Enables the "passive" option in the LCP.  With this option, pppd will
150attempt to initiate a connection; if no reply is received from the
151peer, pppd will then just wait passively for a valid LCP packet from
152the peer, instead of exiting, as it would without this option.
153.SH OPTIONS
154.TP
155.I <local_IP_address>\fB:\fI<remote_IP_address>
156Set the local and/or remote interface IP addresses.  Either one may be
157omitted.  The IP addresses can be specified with a host name or in
158decimal dot notation (e.g. 150.234.56.78).  The default local
159address is the (first) IP address of the system (unless the
160\fInoipdefault\fR
161option is given).  The remote address will be obtained from the peer
162if not specified in any option.  Thus, in simple cases, this option is
163not required.  If a local and/or remote IP address is specified with
164this option, pppd
165will not accept a different value from the peer in the IPCP
166negotiation, unless the \fIipcp-accept-local\fR and/or
167\fIipcp-accept-remote\fR options are given, respectively.
168.TP
169.B ipv6 \fI<local_interface_identifier>\fR,\fI<remote_interface_identifier>
170Set the local and/or remote 64-bit interface identifier. Either one may be
171omitted. The identifier must be specified in standard ascii notation of
172IPv6 addresses (e.g. ::dead:beef). If the
173\fIipv6cp-use-ipaddr\fR
174option is given, the local identifier is the local IPv4 address (see above).
175On systems which supports a unique persistent id, such as EUI-48 derived
176from the Ethernet MAC address, \fIipv6cp-use-persistent\fR option can be
177used to replace the \fIipv6 <local>,<remote>\fR option. Otherwise the
178identifier is randomized.
179.TP
180.B active-filter \fIfilter-expression
181Specifies a packet filter to be applied to data packets to determine
182which packets are to be regarded as link activity, and therefore reset
183the idle timer, or cause the link to be brought up in demand-dialling
184mode.  This option is useful in conjunction with the
185\fBidle\fR option if there are packets being sent or received
186regularly over the link (for example, routing information packets)
187which would otherwise prevent the link from ever appearing to be idle.
188The \fIfilter-expression\fR syntax is as described for tcpdump(1),
189except that qualifiers which are inappropriate for a PPP link, such as
190\fBether\fR and \fBarp\fR, are not permitted.  Generally the filter
191expression should be enclosed in single-quotes to prevent whitespace
192in the expression from being interpreted by the shell. This option
193is currently only available under NetBSD, and then only
194if both the kernel and pppd were compiled with PPP_FILTER defined.
195.TP
196.B allow-ip \fIaddress(es)
197Allow peers to use the given IP address or subnet without
198authenticating themselves.  The parameter is parsed as for each
199element of the list of allowed IP addresses in the secrets files (see
200the AUTHENTICATION section below).
201.TP
202.B bsdcomp \fInr,nt
203Request that the peer compress packets that it sends, using the
204BSD-Compress scheme, with a maximum code size of \fInr\fR bits, and
205agree to compress packets sent to the peer with a maximum code size of
206\fInt\fR bits.  If \fInt\fR is not specified, it defaults to the value
207given for \fInr\fR.  Values in the range 9 to 15 may be used for
208\fInr\fR and \fInt\fR; larger values give better compression but
209consume more kernel memory for compression dictionaries.
210Alternatively, a value of 0 for \fInr\fR or \fInt\fR disables
211compression in the corresponding direction.  Use \fInobsdcomp\fR or
212\fIbsdcomp 0\fR to disable BSD-Compress compression entirely.
213.TP
214.B cdtrcts
215Use a non-standard hardware flow control (i.e. DTR/CTS) to control
216the flow of data on the serial port.  If neither the \fIcrtscts\fR,
217the \fInocrtscts\fR, the \fIcdtrcts\fR nor the \fInocdtrcts\fR
218option is given, the hardware flow control setting for the serial
219port is left unchanged.
220Some serial ports (such as Macintosh serial ports) lack a true
221RTS output. Such serial ports use this mode to implement true
222bi-directional flow control. The sacrifice is that this flow
223control mode does not permit using DTR as a modem control line.
224.TP
225.B chap-interval \fIn
226If this option is given, pppd will rechallenge the peer every \fIn\fR
227seconds.
228.TP
229.B chap-max-challenge \fIn
230Set the maximum number of CHAP challenge transmissions to \fIn\fR
231(default 10).
232.TP
233.B chap-restart \fIn
234Set the CHAP restart interval (retransmission timeout for challenges)
235to \fIn\fR seconds (default 3).
236.TP
237.B connect-delay \fIn
238Wait for up \fIn\fR milliseconds after the connect script finishes for
239a valid PPP packet from the peer.  At the end of this time, or when a
240valid PPP packet is received from the peer, pppd will commence
241negotiation by sending its first LCP packet.  The default value is
2421000 (1 second).  This wait period only applies if the \fBconnect\fR
243or \fBpty\fR option is used.
244.TP
245.B debug
246Enables connection debugging facilities.
247If this option is given, pppd will log the contents of all
248control packets sent or received in a readable form.  The packets are
249logged through syslog with facility \fIdaemon\fR and level
250\fIdebug\fR.  This information can be directed to a file by setting up
251/etc/syslog.conf appropriately (see syslog.conf(5)).
252.TP
253.B default-asyncmap
254Disable asyncmap negotiation, forcing all control characters to be
255escaped for both the transmit and the receive direction.
256.TP
257.B default-mru
258Disable MRU [Maximum Receive Unit] negotiation.  With this option,
259pppd will use the default MRU value of 1500 bytes for both the
260transmit and receive direction.
261.TP
262.B deflate \fInr,nt
263Request that the peer compress packets that it sends, using the
264Deflate scheme, with a maximum window size of \fI2**nr\fR bytes, and
265agree to compress packets sent to the peer with a maximum window size
266of \fI2**nt\fR bytes.  If \fInt\fR is not specified, it defaults to
267the value given for \fInr\fR.  Values in the range 8 to 15 may be used
268for \fInr\fR and \fInt\fR; larger values give better compression but
269consume more kernel memory for compression dictionaries.
270Alternatively, a value of 0 for \fInr\fR or \fInt\fR disables
271compression in the corresponding direction.  Use \fInodeflate\fR or
272\fIdeflate 0\fR to disable Deflate compression entirely.  (Note: pppd
273requests Deflate compression in preference to BSD-Compress if the peer
274can do either.)
275.TP
276.B demand
277Initiate the link only on demand, i.e. when data traffic is present.
278With this option, the remote IP address must be specified by the user
279on the command line or in an options file.  Pppd will initially
280configure the interface and enable it for IP traffic without
281connecting to the peer.  When traffic is available, pppd will
282connect to the peer and perform negotiation, authentication, etc.
283When this is completed, pppd will commence passing data packets
284(i.e., IP packets) across the link.
285
286The \fIdemand\fR option implies the \fIpersist\fR option.  If this
287behaviour is not desired, use the \fInopersist\fR option after the
288\fIdemand\fR option.  The \fIidle\fR and \fIholdoff\fR
289options are also useful in conjuction with the \fIdemand\fR option.
290.TP
291.B domain \fId
292Append the domain name \fId\fR to the local host name for authentication
293purposes.  For example, if gethostname() returns the name porsche, but
294the fully qualified domain name is porsche.Quotron.COM, you could
295specify \fIdomain Quotron.COM\fR.  Pppd would then use the name
296\fIporsche.Quotron.COM\fR for looking up secrets in the secrets file,
297and as the default name to send to the peer when authenticating itself
298to the peer.  This option is privileged.
299.TP
300.B hide-password
301When logging the contents of PAP packets, this option causes pppd to
302exclude the password string from the log.  This is the default.
303.TP
304.B holdoff \fIn
305Specifies how many seconds to wait before re-initiating the link after
306it terminates.  This option only has any effect if the \fIpersist\fR
307or \fIdemand\fR option is used.  The holdoff period is not applied if
308the link was terminated because it was idle.
309.TP
310.B idle \fIn
311Specifies that pppd should disconnect if the link is idle for \fIn\fR
312seconds.  The link is idle when no data packets (i.e. IP packets) are
313being sent or received.  Note: it is not advisable to use this option
314with the \fIpersist\fR option without the \fIdemand\fR option.
315If the \fBactive-filter\fR
316option is given, data packets which are rejected by the specified
317activity filter also count as the link being idle.
318.TP
319.B ipcp-accept-local
320With this option, pppd will accept the peer's idea of our local IP
321address, even if the local IP address was specified in an option.
322.TP
323.B ipcp-accept-remote
324With this option, pppd will accept the peer's idea of its (remote) IP
325address, even if the remote IP address was specified in an option.
326.TP
327.B ipcp-max-configure \fIn
328Set the maximum number of IPCP configure-request transmissions to
329\fIn\fR (default 10).
330.TP
331.B ipcp-max-failure \fIn
332Set the maximum number of IPCP configure-NAKs returned before starting
333to send configure-Rejects instead to \fIn\fR (default 10).
334.TP
335.B ipcp-max-terminate \fIn
336Set the maximum number of IPCP terminate-request transmissions to
337\fIn\fR (default 3).
338.TP
339.B ipcp-restart \fIn
340Set the IPCP restart interval (retransmission timeout) to \fIn\fR
341seconds (default 3).
342.TP
343.B ipparam \fIstring
344Provides an extra parameter to the ip-up and ip-down scripts.  If this
345option is given, the \fIstring\fR supplied is given as the 6th
346parameter to those scripts.
347.TP
348.B ipv6cp-max-configure \fIn
349Set the maximum number of IPv6CP configure-request transmissions to
350\fIn\fR (default 10).
351.TP
352.B ipv6cp-max-failure \fIn
353Set the maximum number of IPv6CP configure-NAKs returned before starting
354to send configure-Rejects instead to \fIn\fR (default 10).
355.TP
356.B ipv6cp-max-terminate \fIn
357Set the maximum number of IPv6CP terminate-request transmissions to
358\fIn\fR (default 3).
359.TP
360.B ipv6cp-restart \fIn
361Set the IPv6CP restart interval (retransmission timeout) to \fIn\fR
362seconds (default 3).
363.TP
364.B ipx
365Enable the IPXCP and IPX protocols.  This option is presently only
366supported under Linux, and only if your kernel has been configured to
367include IPX support.
368.TP
369.B ipx-network \fIn
370Set the IPX network number in the IPXCP configure request frame to
371\fIn\fR, a hexadecimal number (without a leading 0x).  There is no
372valid default.  If this option is not specified, the network number is
373obtained from the peer.  If the peer does not have the network number,
374the IPX protocol will not be started.
375.TP
376.B ipx-node \fIn\fB:\fIm
377Set the IPX node numbers. The two node numbers are separated from each
378other with a colon character. The first number \fIn\fR is the local
379node number. The second number \fIm\fR is the peer's node number. Each
380node number is a hexadecimal number, at most 10 digits long. The node
381numbers on the ipx-network must be unique. There is no valid
382default. If this option is not specified then the node numbers are
383obtained from the peer.
384.TP
385.B ipx-router-name \fI<string>
386Set the name of the router. This is a string and is sent to the peer
387as information data.
388.TP
389.B ipx-routing \fIn
390Set the routing protocol to be received by this option. More than one
391instance of \fIipx-routing\fR may be specified. The '\fInone\fR'
392option (0) may be specified as the only instance of ipx-routing. The
393values may be \fI0\fR for \fINONE\fR, \fI2\fR for \fIRIP/SAP\fR, and
394\fI4\fR for \fINLSP\fR.
395.TP
396.B ipxcp-accept-local
397Accept the peer's NAK for the node number specified in the ipx-node
398option. If a node number was specified, and non-zero, the default is
399to insist that the value be used. If you include this option then you
400will permit the peer to override the entry of the node number.
401.TP
402.B ipxcp-accept-network
403Accept the peer's NAK for the network number specified in the
404ipx-network option. If a network number was specified, and non-zero, the
405default is to insist that the value be used. If you include this
406option then you will permit the peer to override the entry of the node
407number.
408.TP
409.B ipxcp-accept-remote
410Use the peer's network number specified in the configure request
411frame. If a node number was specified for the peer and this option was
412not specified, the peer will be forced to use the value which you have
413specified.
414.TP
415.B ipxcp-max-configure \fIn
416Set the maximum number of IPXCP configure request frames which the
417system will send to \fIn\fR. The default is 10.
418.TP
419.B ipxcp-max-failure \fIn
420Set the maximum number of IPXCP NAK frames which the local system will
421send before it rejects the options. The default value is 3.
422.TP
423.B ipxcp-max-terminate \fIn
424Set the maximum nuber of IPXCP terminate request frames before the
425local system considers that the peer is not listening to them. The
426default value is 3.
427.TP
428.B kdebug \fIn
429Enable debugging code in the kernel-level PPP driver.  The argument
430\fIn\fR is a number which is the sum of the following values: 1 to
431enable general debug messages, 2 to request that the contents of
432received packets be printed, and 4 to request that the contents of
433transmitted packets be printed.  On most systems, messages printed by
434the kernel are logged by syslog(1) to a file as directed in the
435/etc/syslog.conf configuration file.
436.TP
437.B ktune
438Enables pppd to alter kernel settings as appropriate.  Under Linux,
439pppd will enable IP forwarding (i.e. set /proc/sys/net/ipv4/ip_forward
440to 1) if the \fIproxyarp\fR option is used, and will enable the
441dynamic IP address option (i.e. set /proc/sys/net/ipv4/ip_dynaddr to
4421) in demand mode if the local address changes.
443.TP
444.B lcp-echo-failure \fIn
445If this option is given, pppd will presume the peer to be dead
446if \fIn\fR LCP echo-requests are sent without receiving a valid LCP
447echo-reply.  If this happens, pppd will terminate the
448connection.  Use of this option requires a non-zero value for the
449\fIlcp-echo-interval\fR parameter.  This option can be used to enable
450pppd to terminate after the physical connection has been broken
451(e.g., the modem has hung up) in situations where no hardware modem
452control lines are available.
453.TP
454.B lcp-echo-interval \fIn
455If this option is given, pppd will send an LCP echo-request frame to
456the peer every \fIn\fR seconds.  Normally the peer should respond to
457the echo-request by sending an echo-reply.  This option can be used
458with the \fIlcp-echo-failure\fR option to detect that the peer is no
459longer connected.
460.TP
461.B lcp-max-configure \fIn
462Set the maximum number of LCP configure-request transmissions to
463\fIn\fR (default 10).
464.TP
465.B lcp-max-failure \fIn
466Set the maximum number of LCP configure-NAKs returned before starting
467to send configure-Rejects instead to \fIn\fR (default 10).
468.TP
469.B lcp-max-terminate \fIn
470Set the maximum number of LCP terminate-request transmissions to
471\fIn\fR (default 3).
472.TP
473.B lcp-restart \fIn
474Set the LCP restart interval (retransmission timeout) to \fIn\fR
475seconds (default 3).
476.TP
477.B linkname \fIname\fR
478Sets the logical name of the link to \fIname\fR.  Pppd will create a
479file named \fBppp-\fIname\fB.pid\fR in /var/run (or /etc/ppp on some
480systems) containing its process ID.  This can be useful in determining
481which instance of pppd is responsible for the link to a given peer
482system.  This is a privileged option.
483.TP
484.B local
485Don't use the modem control lines.  With this option, pppd will ignore
486the state of the CD (Carrier Detect) signal from the modem and will
487not change the state of the DTR (Data Terminal Ready) signal.
488.TP
489.B logfd \fIn
490Send log messages to file descriptor \fIn\fR.  Pppd will send log
491messages to at most one file or file descriptor (as well as sending
492the log messages to syslog), so this option and the \fBlogfile\fR
493option are mutually exclusive.  The default is for pppd to send log
494messages to stdout (file descriptor 1), unless the serial port is
495already open on stdout.
496.TP
497.B logfile \fIfilename
498Append log messages to the file \fIfilename\fR (as well as sending the
499log messages to syslog).  The file is opened with the privileges of
500the user who invoked pppd, in append mode.
501.TP
502.B login
503Use the system password database for authenticating the peer using
504PAP, and record the user in the system wtmp file.  Note that the peer
505must have an entry in the /etc/ppp/pap-secrets file as well as the
506system password database to be allowed access.
507.TP
508.B maxconnect \fIn
509Terminate the connection when it has been available for network
510traffic for \fIn\fR seconds (i.e. \fIn\fR seconds after the first
511network control protocol comes up).
512.TP
513.B maxfail \fIn
514Terminate after \fIn\fR consecutive failed connection attempts.  A
515value of 0 means no limit.  The default value is 10.
516.TP
517.B modem
518Use the modem control lines.  This option is the default.  With this
519option, pppd will wait for the CD (Carrier Detect) signal from the
520modem to be asserted when opening the serial device (unless a connect
521script is specified), and it will drop the DTR (Data Terminal Ready)
522signal briefly when the connection is terminated and before executing
523the connect script.  On Ultrix, this option implies hardware flow
524control, as for the \fIcrtscts\fR option.
525.TP
526.B ms-dns \fI<addr>
527If pppd is acting as a server for Microsoft Windows clients, this
528option allows pppd to supply one or two DNS (Domain Name Server)
529addresses to the clients.  The first instance of this option specifies
530the primary DNS address; the second instance (if given) specifies the
531secondary DNS address.  (This option was present in some older
532versions of pppd under the name \fBdns-addr\fR.)
533.TP
534.B ms-wins \fI<addr>
535If pppd is acting as a server for Microsoft Windows or "Samba"
536clients, this option allows pppd to supply one or two WINS (Windows
537Internet Name Services) server addresses to the clients.  The first
538instance of this option specifies the primary WINS address; the second
539instance (if given) specifies the secondary WINS address.
540.TP
541.B name \fIname
542Set the name of the local system for authentication purposes to
543\fIname\fR.  This is a privileged option.  With this option, pppd will
544use lines in the secrets files which have \fIname\fR as the second
545field when looking for a secret to use in authenticating the peer.  In
546addition, unless overridden with the \fIuser\fR option, \fIname\fR
547will be used as the name to send to the peer when authenticating the
548local system to the peer.  (Note that pppd does not append the domain
549name to \fIname\fR.)
550.TP
551.B netmask \fIn
552Set the interface netmask to \fIn\fR, a 32 bit netmask in "decimal dot"
553notation (e.g. 255.255.255.0).  If this option is given, the value
554specified is ORed with the default netmask.  The default netmask is
555chosen based on the negotiated remote IP address; it is the
556appropriate network mask for the class of the remote IP address, ORed
557with the netmasks for any non point-to-point network interfaces in the
558system which are on the same network.  (Note: on some platforms, pppd
559will always use 255.255.255.255 for the netmask, if that is the only
560appropriate value for a point-to-point interface.)
561.TP
562.B noaccomp
563Disable Address/Control compression in both directions (send and
564receive).
565.TP
566.B noauth
567Do not require the peer to authenticate itself.  This option is
568privileged.
569.TP
570.B nobsdcomp
571Disables BSD-Compress compression; \fBpppd\fR will not request or
572agree to compress packets using the BSD-Compress scheme.
573.TP
574.B noccp
575Disable CCP (Compression Control Protocol) negotiation.  This option
576should only be required if the peer is buggy and gets confused by
577requests from pppd for CCP negotiation.
578.TP
579.B nocrtscts
580Disable hardware flow control (i.e. RTS/CTS) on the serial port.
581If neither the \fIcrtscts\fR nor the \fInocrtscts\fR nor the
582\fIcdtrcts\fR nor the \fInodtrcts\fR option is given, the hardware
583flow control setting for the serial port is left unchanged.
584.TP
585.B nodtrcts
586This option is a synonym for \fInocrtscts\fR. Either of these options will
587disable both forms of hardware flow control.
588.TP
589.B nodefaultroute
590Disable the \fIdefaultroute\fR option.  The system administrator who
591wishes to prevent users from creating default routes with pppd
592can do so by placing this option in the /etc/ppp/options file.
593.TP
594.B nodeflate
595Disables Deflate compression; pppd will not request or agree to
596compress packets using the Deflate scheme.
597.TP
598.B nodetach
599Don't detach from the controlling terminal.  Without this option, if a
600serial device other than the terminal on the standard input is
601specified, pppd will fork to become a background process.
602.TP
603.B noip
604Disable IPCP negotiation and IP communication.  This option should
605only be required if the peer is buggy and gets confused by requests
606from pppd for IPCP negotiation.
607.TP
608.B noipv6
609Disable IPv6CP negotiation and IPv6 communication. This option should
610only be required if the peer is buggy and gets confused by requests
611from pppd for IPv6CP negotiation.
612.TP
613.B noipdefault
614Disables the default behaviour when no local IP address is specified,
615which is to determine (if possible) the local IP address from the
616hostname.  With this option, the peer will have to supply the local IP
617address during IPCP negotiation (unless it specified explicitly on the
618command line or in an options file).
619.TP
620.B noipx
621Disable the IPXCP and IPX protocols.  This option should only be
622required if the peer is buggy and gets confused by requests from pppd
623for IPXCP negotiation.
624.TP
625.B noktune
626Opposite of the \fIktune\fR option; disables pppd from changing system
627settings.
628.TP
629.B nolog
630Do not send log messages to a file or file descriptor.  This option
631cancels the \fBlogfd\fR and \fBlogfile\fR options.
632.B nomagic
633Disable magic number negotiation.  With this option, pppd cannot
634detect a looped-back line.  This option should only be needed if the
635peer is buggy.
636.TP
637.B nopcomp
638Disable protocol field compression negotiation in both the receive and
639the transmit direction.
640.TP
641.B nopersist
642Exit once a connection has been made and terminated.  This is the
643default unless the \fIpersist\fR or \fIdemand\fR option has been
644specified.
645.TP
646.B nopredictor1
647Do not accept or agree to Predictor-1 compression.
648.TP
649.B noproxyarp
650Disable the \fIproxyarp\fR option.  The system administrator who
651wishes to prevent users from creating proxy ARP entries with pppd can
652do so by placing this option in the /etc/ppp/options file.
653.TP
654.B notty
655Normally, pppd requires a terminal device.  With this option, pppd
656will allocate itself a pseudo-tty master/slave pair and use the slave
657as its terminal device.  Pppd will create a child process to act as a
658`character shunt' to transfer characters between the pseudo-tty master
659and its standard input and output.  Thus pppd will transmit characters
660on its standard output and receive characters on its standard input
661even if they are not terminal devices.  This option increases the
662latency and CPU overhead of transferring data over the ppp interface
663as all of the characters sent and received must flow through the
664character shunt process.  An explicit device name may not be given if
665this option is used.
666.TP
667.B novj
668Disable Van Jacobson style TCP/IP header compression in both the
669transmit and the receive direction.
670.TP
671.B novjccomp
672Disable the connection-ID compression option in Van Jacobson style
673TCP/IP header compression.  With this option, pppd will not omit the
674connection-ID byte from Van Jacobson compressed TCP/IP headers, nor
675ask the peer to do so.
676.TP
677.B papcrypt
678Indicates that all secrets in the /etc/ppp/pap-secrets file which are
679used for checking the identity of the peer are encrypted, and thus
680pppd should not accept a password which, before encryption, is
681identical to the secret from the /etc/ppp/pap-secrets file.
682.TP
683.B pap-max-authreq \fIn
684Set the maximum number of PAP authenticate-request transmissions to
685\fIn\fR (default 10).
686.TP
687.B pap-restart \fIn
688Set the PAP restart interval (retransmission timeout) to \fIn\fR
689seconds (default 3).
690.TP
691.B pap-timeout \fIn
692Set the maximum time that pppd will wait for the peer to authenticate
693itself with PAP to \fIn\fR seconds (0 means no limit).
694.TP
695.B pass-filter \fIfilter-expression
696Specifies a packet filter to applied to data packets being sent or
697received to determine which packets should be allowed to pass.
698Packets which are rejected by the filter are silently discarded.  This
699option can be used to prevent specific network daemons (such as
700routed) using up link bandwidth, or to provide a basic firewall
701capability.
702The \fIfilter-expression\fR syntax is as described for tcpdump(1),
703except that qualifiers which are inappropriate for a PPP link, such as
704\fBether\fR and \fBarp\fR, are not permitted.  Generally the filter
705expression should be enclosed in single-quotes to prevent whitespace
706in the expression from being interpreted by the shell.  Note that it
707is possible to apply different constraints to incoming and outgoing
708packets using the \fBinbound\fR and \fBoutbound\fR qualifiers. This
709option is currently only available under NetBSD, and then only if both
710the kernel and pppd were compiled with PPP_FILTER defined.
711.TP
712.B persist
713Do not exit after a connection is terminated; instead try to reopen
714the connection.
715.TP
716.B plugin \fIfilename
717Load the shared library object file \fIfilename\fR as a plugin.  This
718is a privileged option.
719.TP
720.B predictor1
721Request that the peer compress frames that it sends using Predictor-1
722compression, and agree to compress transmitted frames with Predictor-1
723if requested.  This option has no effect unless the kernel driver
724supports Predictor-1 compression.
725.TP
726.B privgroup \fIgroup-name
727Allows members of group \fIgroup-name\fR to use privileged options.
728This is a privileged option.  Use of this option requires care as
729there is no guarantee that members of \fIgroup-name\fR cannot use pppd
730to become root themselves.  Consider it equivalent to putting the
731members of \fIgroup-name\fR in the kmem or disk group.
732.TP
733.B proxyarp
734Add an entry to this system's ARP [Address Resolution Protocol] table
735with the IP address of the peer and the Ethernet address of this
736system.  This will have the effect of making the peer appear to other
737systems to be on the local ethernet.
738.TP
739.B pty \fIscript
740Specifies that the command \fIscript\fR is to be used to communicate
741rather than a specific terminal device.  Pppd will allocate itself a
742pseudo-tty master/slave pair and use the slave as its terminal
743device.  The \fIscript\fR will be run in a child process with the
744pseudo-tty master as its standard input and output.  An explicit
745device name may not be given if this option is used.  (Note: if the
746\fIrecord\fR option is used in conjuction with the \fIpty\fR option,
747the child process will have pipes on its standard input and output.)
748.TP
749.B receive-all
750With this option, pppd will accept all control characters from the
751peer, including those marked in the receive asyncmap.  Without this
752option, pppd will discard those characters as specified in RFC1662.
753This option should only be needed if the peer is buggy.
754.TP
755.B record \fIfilename
756Specifies that pppd should record all characters sent and received to
757a file named \fIfilename\fR.  This file is opened in append mode,
758using the user's user-ID and permissions.  This option is implemented
759using a pseudo-tty and a process to transfer characters between the
760pseudo-tty and the real serial device, so it will increase the latency
761and CPU overhead of transferring data over the ppp interface.  The
762characters are stored in a tagged format with timestamps, which can be
763displayed in readable form using the pppdump(8) program.
764.TP
765.B remotename \fIname
766Set the assumed name of the remote system for authentication purposes
767to \fIname\fR.
768.TP
769.B refuse-chap
770With this option, pppd will not agree to authenticate itself to the
771peer using CHAP.
772.TP
773.B refuse-pap
774With this option, pppd will not agree to authenticate itself to the
775peer using PAP.
776.TP
777.B require-chap
778Require the peer to authenticate itself using CHAP [Challenge
779Handshake Authentication Protocol] authentication.
780.TP
781.B require-pap
782Require the peer to authenticate itself using PAP [Password
783Authentication Protocol] authentication.
784.TP
785.B show-password
786When logging the contents of PAP packets, this option causes pppd to
787show the password string in the log message.
788.TP
789.B silent
790With this option, pppd will not transmit LCP packets to initiate a
791connection until a valid LCP packet is received from the peer (as for
792the `passive' option with ancient versions of pppd).
793.TP
794.B sync
795Use synchronous HDLC serial encoding instead of asynchronous.
796The device used by pppd with this option must have sync support.
797Currently supports Microgate SyncLink adapters
798under Linux and FreeBSD 2.2.8 and later.
799.TP
800.B updetach
801With this option, pppd will detach from its controlling terminal once
802it has successfully established the ppp connection (to the point where
803the first network control protocol, usually the IP control protocol,
804has come up).
805.TP
806.B usehostname
807Enforce the use of the hostname (with domain name appended, if given)
808as the name of the local system for authentication purposes (overrides
809the \fIname\fR option).  This option is not normally needed since the
810\fIname\fR option is privileged.
811.TP
812.B usepeerdns
813Ask the peer for up to 2 DNS server addresses.  The addresses supplied
814by the peer (if any) are passed to the /etc/ppp/ip-up script in the
815environment variables DNS1 and DNS2.  In addition, pppd will create an
816/etc/ppp/resolv.conf file containing one or two nameserver lines with
817the address(es) supplied by the peer.
818.TP
819.B user \fIname
820Sets the name used for authenticating the local system to the peer to
821\fIname\fR.
822.TP
823.B vj-max-slots \fIn
824Sets the number of connection slots to be used by the Van Jacobson
825TCP/IP header compression and decompression code to \fIn\fR, which
826must be between 2 and 16 (inclusive).
827.TP
828.B welcome \fIscript
829Run the executable or shell command specified by \fIscript\fR before
830initiating PPP negotiation, after the connect script (if any) has
831completed.  A value for this option from a privileged source cannot be
832overridden by a non-privileged user.
833.TP
834.B xonxoff
835Use software flow control (i.e. XON/XOFF) to control the flow of data on
836the serial port.
837.SH OPTIONS FILES
838Options can be taken from files as well as the command line.  Pppd
839reads options from the files /etc/ppp/options, ~/.ppprc and
840/etc/ppp/options.\fIttyname\fR (in that order) before processing the
841options on the command line.  (In fact, the command-line options are
842scanned to find the terminal name before the options.\fIttyname\fR
843file is read.)  In forming the name of the options.\fIttyname\fR file,
844the initial /dev/ is removed from the terminal name, and any remaining
845/ characters are replaced with dots.
846.PP
847An options file is parsed into a series of words, delimited by
848whitespace.  Whitespace can be included in a word by enclosing the
849word in double-quotes (").  A backslash (\\) quotes the following character.
850A hash (#) starts a comment, which continues until the end of the
851line.  There is no restriction on using the \fIfile\fR or \fIcall\fR
852options within an options file.
853.SH SECURITY
854.I pppd
855provides system administrators with sufficient access control that PPP
856access to a server machine can be provided to legitimate users without
857fear of compromising the security of the server or the network it's
858on.  This control is provided through restrictions on which IP
859addresses the peer may use, based on its authenticated identity (if
860any), and through restrictions on which options a non-privileged user
861may use.  Several of pppd's options are privileged, in particular
862those which permit potentially insecure configurations; these options
863are only accepted in files which are under the control of the system
864administrator, or if pppd is being run by root.
865.PP
866The default behaviour of pppd is to allow an unauthenticated peer to
867use a given IP address only if the system does not already have a
868route to that IP address.  For example, a system with a
869permanent connection to the wider internet will normally have a
870default route, and thus all peers will have to authenticate themselves
871in order to set up a connection.  On such a system, the \fIauth\fR
872option is the default.  On the other hand, a system where the
873PPP link is the only connection to the internet will not normally have
874a default route, so the peer will be able to use almost any IP address
875without authenticating itself.
876.PP
877As indicated above, some security-sensitive options are privileged,
878which means that they may not be used by an ordinary non-privileged
879user running a setuid-root pppd, either on the command line, in the
880user's ~/.ppprc file, or in an options file read using the \fIfile\fR
881option.  Privileged options may be used in /etc/ppp/options file or in
882an options file read using the \fIcall\fR option.  If pppd is being
883run by the root user, privileged options can be used without
884restriction.
885.PP
886When opening the device, pppd uses either the invoking user's user ID
887or the root UID (that is, 0), depending on whether the device name was
888specified by the user or the system administrator.  If the device name
889comes from a privileged source, that is, /etc/ppp/options or an
890options file read using the \fIcall\fR option, pppd uses full root
891privileges when opening the device.  Thus, by creating an appropriate
892file under /etc/ppp/peers, the system administrator can allow users to
893establish a ppp connection via a device which they would not normally
894have permission to access.  Otherwise pppd uses the invoking user's
895real UID when opening the device.
896.SH AUTHENTICATION
897Authentication is the process whereby one peer convinces the other of
898its identity.  This involves the first peer sending its name to the
899other, together with some kind of secret information which could only
900come from the genuine authorized user of that name.  In such an
901exchange, we will call the first peer the "client" and the other the
902"server".  The client has a name by which it identifies itself to the
903server, and the server also has a name by which it identifies itself
904to the client.  Generally the genuine client shares some secret (or
905password) with the server, and authenticates itself by proving that it
906knows that secret.  Very often, the names used for authentication
907correspond to the internet hostnames of the peers, but this is not
908essential.
909.LP
910At present, pppd supports two authentication protocols: the Password
911Authentication Protocol (PAP) and the Challenge Handshake
912Authentication Protocol (CHAP).  PAP involves the client sending its
913name and a cleartext password to the server to authenticate itself.
914In contrast, the server initiates the CHAP authentication exchange by
915sending a challenge to the client (the challenge packet includes the
916server's name).  The client must respond with a response which
917includes its name plus a hash value derived from the shared secret and
918the challenge, in order to prove that it knows the secret.
919.LP
920The PPP protocol, being symmetrical, allows both peers to require the
921other to authenticate itself.  In that case, two separate and
922independent authentication exchanges will occur.  The two exchanges
923could use different authentication protocols, and in principle,
924different names could be used in the two exchanges.
925.LP
926The default behaviour of pppd is to agree to authenticate if
927requested, and to not require authentication from the peer.  However,
928pppd will not agree to authenticate itself with a particular protocol
929if it has no secrets which could be used to do so.
930.LP
931Pppd stores secrets for use in authentication in secrets
932files (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP).
933Both secrets files have the same format.  The secrets files can
934contain secrets for pppd to use in authenticating itself to other
935systems, as well as secrets for pppd to use when authenticating other
936systems to itself.
937.LP
938Each line in a secrets file contains one secret.  A given secret is
939specific to a particular combination of client and server - it can
940only be used by that client to authenticate itself to that server.
941Thus each line in a secrets file has at least 3 fields: the name of
942the client, the name of the server, and the secret.  These fields may
943be followed by a list of the IP addresses that the specified client
944may use when connecting to the specified server.
945.LP
946A secrets file is parsed into words as for a options file, so the
947client name, server name and secrets fields must each be one word,
948with any embedded spaces or other special characters quoted or
949escaped.  Note that case is significant in the client and server names
950and in the secret.
951.LP
952If the secret starts with an `@', what follows is assumed to be the
953name of a file from which to read the secret.  A "*" as the client or
954server name matches any name.  When selecting a secret, pppd takes the
955best match, i.e.  the match with the fewest wildcards.
956.LP
957Any following words on the same line are taken to be a list of
958acceptable IP addresses for that client.  If there are only 3 words on
959the line, or if the first word is "-", then all IP addresses are
960disallowed.  To allow any address, use "*".  A word starting with "!"
961indicates that the specified address is \fInot\fR acceptable.  An
962address may be followed by "/" and a number \fIn\fR, to indicate a
963whole subnet, i.e. all addresses which have the same value in the most
964significant \fIn\fR bits.  In this form, the address may be followed
965by a plus sign ("+") to indicate that one address from the subnet is
966authorized, based on the ppp network interface unit number in use.
967In this case, the host part of the address will be set to the unit
968number plus one.
969.LP
970Thus a secrets file contains both secrets for use in authenticating
971other hosts, plus secrets which we use for authenticating ourselves to
972others.  When pppd is authenticating the peer (checking the peer's
973identity), it chooses a secret with the peer's name in the first
974field and the name of the local system in the second field.  The
975name of the local system defaults to the hostname, with the domain
976name appended if the \fIdomain\fR option is used.  This default can be
977overridden with the \fIname\fR option, except when the
978\fIusehostname\fR option is used.
979.LP
980When pppd is choosing a secret to use in authenticating itself to the
981peer, it first determines what name it is going to use to identify
982itself to the peer.  This name can be specified by the user with the
983\fIuser\fR option.  If this option is not used, the name defaults to
984the name of the local system, determined as described in the previous
985paragraph.  Then pppd looks for a secret with this name in the first
986field and the peer's name in the second field.  Pppd will know the
987name of the peer if CHAP authentication is being used, because the
988peer will have sent it in the challenge packet.  However, if PAP is being
989used, pppd will have to determine the peer's name from the options
990specified by the user.  The user can specify the peer's name directly
991with the \fIremotename\fR option.  Otherwise, if the remote IP address
992was specified by a name (rather than in numeric form), that name will
993be used as the peer's name.  Failing that, pppd will use the null
994string as the peer's name.
995.LP
996When authenticating the peer with PAP, the supplied password is first
997compared with the secret from the secrets file.  If the password
998doesn't match the secret, the password is encrypted using crypt() and
999checked against the secret again.  Thus secrets for authenticating the
1000peer can be stored in encrypted form if desired.  If the
1001\fIpapcrypt\fR option is given, the first (unencrypted) comparison is
1002omitted, for better security.
1003.LP
1004Furthermore, if the \fIlogin\fR option was specified, the username and
1005password are also checked against the system password database.  Thus,
1006the system administrator can set up the pap-secrets file to allow PPP
1007access only to certain users, and to restrict the set of IP addresses
1008that each user can use.  Typically, when using the \fIlogin\fR option,
1009the secret in /etc/ppp/pap-secrets would be "", which will match any
1010password supplied by the peer.  This avoids the need to have the same
1011secret in two places.
1012.LP
1013Authentication must be satisfactorily completed before IPCP (or any
1014other Network Control Protocol) can be started.  If the peer is
1015required to authenticate itself, and fails to do so, pppd will
1016terminated the link (by closing LCP).  If IPCP negotiates an
1017unacceptable IP address for the remote host, IPCP will be closed.  IP
1018packets can only be sent or received when IPCP is open.
1019.LP
1020In some cases it is desirable to allow some hosts which can't
1021authenticate themselves to connect and use one of a restricted set of
1022IP addresses, even when the local host generally requires
1023authentication.  If the peer refuses to authenticate itself when
1024requested, pppd takes that as equivalent to authenticating with PAP
1025using the empty string for the username and password.  Thus, by adding
1026a line to the pap-secrets file which specifies the empty string for
1027the client and password, it is possible to allow restricted access to
1028hosts which refuse to authenticate themselves.
1029.SH ROUTING
1030.LP
1031When IPCP negotiation is completed successfully, pppd will inform the
1032kernel of the local and remote IP addresses for the ppp interface.
1033This is sufficient to create a host route to the remote end of the
1034link, which will enable the peers to exchange IP packets.
1035Communication with other machines generally requires further
1036modification to routing tables and/or ARP (Address Resolution
1037Protocol) tables.  In most cases the \fIdefaultroute\fR and/or
1038\fIproxyarp\fR options are sufficient for this, but in some cases
1039further intervention is required.  The /etc/ppp/ip-up script can be
1040used for this.
1041.LP
1042Sometimes it is desirable to add a default route through the remote
1043host, as in the case of a machine whose only connection to the
1044Internet is through the ppp interface.  The \fIdefaultroute\fR option
1045causes pppd to create such a default route when IPCP comes up, and
1046delete it when the link is terminated.
1047.LP
1048In some cases it is desirable to use proxy ARP, for example on a
1049server machine connected to a LAN, in order to allow other hosts to
1050communicate with the remote host.  The \fIproxyarp\fR option causes
1051pppd to look for a network interface on the same subnet as the remote
1052host (an interface supporting broadcast and ARP, which is up and not a
1053point-to-point or loopback interface).  If found, pppd creates a
1054permanent, published ARP entry with the IP address of the remote host
1055and the hardware address of the network interface found.
1056.LP
1057When the \fIdemand\fR option is used, the interface IP addresses have
1058already been set at the point when IPCP comes up.  If pppd has not
1059been able to negotiate the same addresses that it used to configure
1060the interface (for example when the peer is an ISP that uses dynamic
1061IP address assignment), pppd has to change the interface IP addresses
1062to the negotiated addresses.  This may disrupt existing connections,
1063and the use of demand dialling with peers that do dynamic IP address
1064assignment is not recommended.
1065.SH EXAMPLES
1066.LP
1067The following examples assume that the /etc/ppp/options file contains
1068the \fIauth\fR option (as in the default /etc/ppp/options file in the
1069ppp distribution).
1070.LP
1071Probably the most common use of pppd is to dial out to an ISP.  This
1072can be done with a command such as
1073.IP
1074pppd call isp
1075.LP
1076where the /etc/ppp/peers/isp file is set up by the system
1077administrator to contain something like this:
1078.IP
1079ttyS0 19200 crtscts
1080.br
1081connect '/usr/sbin/chat -v -f /etc/ppp/chat-isp'
1082.br
1083noauth
1084.LP
1085In this example, we are using chat to dial the ISP's modem and go
1086through any logon sequence required.  The /etc/ppp/chat-isp file
1087contains the script used by chat; it could for example contain
1088something like this:
1089.IP
1090ABORT "NO CARRIER"
1091.br
1092ABORT "NO DIALTONE"
1093.br
1094ABORT "ERROR"
1095.br
1096ABORT "NO ANSWER"
1097.br
1098ABORT "BUSY"
1099.br
1100ABORT "Username/Password Incorrect"
1101.br
1102"" "at"
1103.br
1104OK "at&d0&c1"
1105.br
1106OK "atdt2468135"
1107.br
1108"name:" "^Umyuserid"
1109.br
1110"word:" "\\qmypassword"
1111.br
1112"ispts" "\\q^Uppp"
1113.br
1114"~-^Uppp-~"
1115.LP
1116See the chat(8) man page for details of chat scripts.
1117.LP
1118Pppd can also be used to provide a dial-in ppp service for users.  If
1119the users already have login accounts, the simplest way to set up the
1120ppp service is to let the users log in to their accounts and run pppd
1121(installed setuid-root) with a command such as
1122.IP
1123pppd proxyarp
1124.LP
1125To allow a user to use the PPP facilities, you need to allocate an IP
1126address for that user's machine and create an entry in
1127/etc/ppp/pap-secrets or /etc/ppp/chap-secrets (depending on which
1128authentication method the PPP implementation on the user's machine
1129supports), so that the user's
1130machine can authenticate itself.  For example, if Joe has a machine
1131called "joespc" which is to be allowed to dial in to the machine
1132called "server" and use the IP address joespc.my.net, you would add an
1133entry like this to /etc/ppp/pap-secrets or /etc/ppp/chap-secrets:
1134.IP
1135joespc  server  "joe's secret"  joespc.my.net
1136.LP
1137Alternatively, you can create a username called (for example) "ppp",
1138whose login shell is pppd and whose home directory is /etc/ppp.
1139Options to be used when pppd is run this way can be put in
1140/etc/ppp/.ppprc.
1141.LP
1142If your serial connection is any more complicated than a piece of
1143wire, you may need to arrange for some control characters to be
1144escaped.  In particular, it is often useful to escape XON (^Q) and
1145XOFF (^S), using \fIasyncmap a0000\fR.  If the path includes a telnet,
1146you probably should escape ^] as well (\fIasyncmap 200a0000\fR).  If
1147the path includes an rlogin, you will need to use the \fIescape ff\fR
1148option on the end which is running the rlogin client, since many
1149rlogin implementations are not transparent; they will remove the
1150sequence [0xff, 0xff, 0x73, 0x73, followed by any 8 bytes] from the
1151stream.
1152.SH DIAGNOSTICS
1153.LP
1154Messages are sent to the syslog daemon using facility LOG_DAEMON.
1155(This can be overriden by recompiling pppd with the macro
1156LOG_PPP defined as the desired facility.)  In order to see the error
1157and debug messages, you will need to edit your /etc/syslog.conf file
1158to direct the messages to the desired output device or file.
1159.LP
1160The \fIdebug\fR option causes the contents of all control packets sent
1161or received to be logged, that is, all LCP, PAP, CHAP or IPCP packets.
1162This can be useful if the PPP negotiation does not succeed or if
1163authentication fails.
1164If debugging is enabled at compile time, the \fIdebug\fR option also
1165causes other debugging messages to be logged.
1166.LP
1167Debugging can also be enabled or disabled by sending a SIGUSR1 signal
1168to the pppd process.  This signal acts as a toggle.
1169.SH EXIT STATUS
1170The exit status of pppd is set to indicate whether any error was
1171detected, or the reason for the link being terminated.  The values
1172used are:
1173.TP
1174.B 0
1175Pppd has detached, or otherwise the connection was successfully
1176established and terminated at the peer's request.
1177.TP
1178.B 1
1179An immediately fatal error of some kind occurred, such as an essential
1180system call failing, or running out of virtual memory.
1181.TP
1182.B 2
1183An error was detected in processing the options given, such as two
1184mutually exclusive options being used.
1185.TP
1186.B 3
1187Pppd is not setuid-root and the invoking user is not root.
1188.TP
1189.B 4
1190The kernel does not support PPP, for example, the PPP kernel driver is
1191not included or cannot be loaded.
1192.TP
1193.B 5
1194Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP
1195signal.
1196.TP
1197.B 6
1198The serial port could not be locked.
1199.TP
1200.B 7
1201The serial port could not be opened.
1202.TP
1203.B 8
1204The connect script failed (returned a non-zero exit status).
1205.TP
1206.B 9
1207The command specified as the argument to the \fIpty\fR option could
1208not be run.
1209.TP
1210.B 10
1211The PPP negotiation failed, that is, it didn't reach the point where
1212at least one network protocol (e.g. IP) was running.
1213.TP
1214.B 11
1215The peer system failed (or refused) to authenticate itself.
1216.TP
1217.B 12
1218The link was established successfully and terminated because it was
1219idle.
1220.TP
1221.B 13
1222The link was established successfully and terminated because the
1223connect time limit was reached.
1224.TP
1225.B 14
1226Callback was negotiated and an incoming call should arrive shortly.
1227.TP
1228.B 15
1229The link was terminated because the peer is not responding to echo
1230requests.
1231.TP
1232.B 16
1233The link was terminated by the modem hanging up.
1234.TP
1235.B 17
1236The PPP negotiation failed because serial loopback was detected.
1237.TP
1238.B 18
1239The init script failed (returned a non-zero exit status).
1240.TP
1241.B 19
1242We failed to authenticate ourselves to the peer.
1243.SH SCRIPTS
1244Pppd invokes scripts at various stages in its processing which can be
1245used to perform site-specific ancillary processing.  These scripts are
1246usually shell scripts, but could be executable code files instead.
1247Pppd does not wait for the scripts to finish.  The scripts are
1248executed as root (with the real and effective user-id set to 0), so
1249that they can do things such as update routing tables or run
1250privileged daemons.  Be careful that the contents of these scripts do
1251not compromise your system's security.  Pppd runs the scripts with
1252standard input, output and error redirected to /dev/null, and with an
1253environment that is empty except for some environment variables that
1254give information about the link.  The environment variables that pppd
1255sets are:
1256.TP
1257.B DEVICE
1258The name of the serial tty device being used.
1259.TP
1260.B IFNAME
1261The name of the network interface being used.
1262.TP
1263.B IPLOCAL
1264The IP address for the local end of the link.  This is only set when
1265IPCP has come up.
1266.TP
1267.B IPREMOTE
1268The IP address for the remote end of the link.  This is only set when
1269IPCP has come up.
1270.TP
1271.B PEERNAME
1272The authenticated name of the peer.  This is only set if the peer
1273authenticates itself.
1274.TP
1275.B SPEED
1276The baud rate of the tty device.
1277.TP
1278.B ORIG_UID
1279The real user-id of the user who invoked pppd.
1280.TP
1281.B PPPLOGNAME
1282The username of the real user-id that invoked pppd. This is always set.
1283.P
1284For the ip-down and auth-down scripts, pppd also sets the following
1285variables giving statistics for the connection:
1286.TP
1287.B CONNECT_TIME
1288The number of seconds from when the PPP negotiation started until the
1289connection was terminated.
1290.TP
1291.B BYTES_SENT
1292The number of bytes sent (at the level of the serial port) during the
1293connection.
1294.TP
1295.B BYTES_RCVD
1296The number of bytes received (at the level of the serial port) during
1297the connection.
1298.TP
1299.B LINKNAME
1300The logical name of the link, set with the \fIlinkname\fR option.
1301.P
1302Pppd invokes the following scripts, if they exist.  It is not an error
1303if they don't exist.
1304.TP
1305.B /etc/ppp/auth-up
1306A program or script which is executed after the remote system
1307successfully authenticates itself.  It is executed with the parameters
1308.IP
1309\fIinterface-name peer-name user-name tty-device speed\fR
1310.IP
1311Note that this script is not executed if the peer doesn't authenticate
1312itself, for example when the \fInoauth\fR option is used.
1313.TP
1314.B /etc/ppp/auth-down
1315A program or script which is executed when the link goes down, if
1316/etc/ppp/auth-up was previously executed.  It is executed in the same
1317manner with the same parameters as /etc/ppp/auth-up.
1318.TP
1319.B /etc/ppp/ip-up
1320A program or script which is executed when the link is available for
1321sending and receiving IP packets (that is, IPCP has come up).  It is
1322executed with the parameters
1323.IP
1324\fIinterface-name tty-device speed local-IP-address
1325remote-IP-address ipparam\fR
1326.TP
1327.B /etc/ppp/ip-down
1328A program or script which is executed when the link is no longer
1329available for sending and receiving IP packets.  This script can be
1330used for undoing the effects of the /etc/ppp/ip-up script.  It is
1331invoked in the same manner and with the same parameters as the ip-up
1332script.
1333.TP
1334.B /etc/ppp/ipv6-up
1335Like /etc/ppp/ip-up, except that it is executed when the link is available
1336for sending and receiving IPv6 packets. It is executed with the parameters
1337.IP
1338\fIinterface-name tty-device speed local-link-local-address
1339remote-link-local-address ipparam\fR
1340.TP
1341.B /etc/ppp/ipv6-down
1342Similar to /etc/ppp/ip-down, but it is executed when IPv6 packets can no
1343longer be transmitted on the link. It is executed with the same parameters
1344as the ipv6-up script.
1345.TP
1346.B /etc/ppp/ipx-up
1347A program or script which is executed when the link is available for
1348sending and receiving IPX packets (that is, IPXCP has come up).  It is
1349executed with the parameters
1350.IP
1351\fIinterface-name tty-device speed network-number local-IPX-node-address
1352remote-IPX-node-address local-IPX-routing-protocol remote-IPX-routing-protocol
1353local-IPX-router-name remote-IPX-router-name ipparam pppd-pid\fR
1354.IP
1355The local-IPX-routing-protocol and remote-IPX-routing-protocol field
1356may be one of the following:
1357.IP
1358NONE      to indicate that there is no routing protocol
1359.br
1360RIP       to indicate that RIP/SAP should be used
1361.br
1362NLSP      to indicate that Novell NLSP should be used
1363.br
1364RIP NLSP  to indicate that both RIP/SAP and NLSP should be used
1365.TP
1366.B /etc/ppp/ipx-down
1367A program or script which is executed when the link is no longer
1368available for sending and receiving IPX packets.  This script can be
1369used for undoing the effects of the /etc/ppp/ipx-up script.  It is
1370invoked in the same manner and with the same parameters as the ipx-up
1371script.
1372.SH FILES
1373.TP
1374.B /var/run/ppp\fIn\fB.pid \fR(BSD or Linux), \fB/etc/ppp/ppp\fIn\fB.pid \fR(others)
1375Process-ID for pppd process on ppp interface unit \fIn\fR.
1376.TP
1377.B /var/run/ppp-\fIname\fB.pid \fR(BSD or Linux), \fB/etc/ppp/ppp-\fIname\fB.pid \fR(others)
1378Process-ID for pppd process for logical link \fIname\fR (see the
1379\fIlinkname\fR option).
1380.TP
1381.B /etc/ppp/pap-secrets
1382Usernames, passwords and IP addresses for PAP authentication.  This
1383file should be owned by root and not readable or writable by any other
1384user.  Pppd will log a warning if this is not the case.
1385.TP
1386.B /etc/ppp/chap-secrets
1387Names, secrets and IP addresses for CHAP authentication.  As for
1388/etc/ppp/pap-secrets, this file should be owned by root and not
1389readable or writable by any other user.  Pppd will log a warning if
1390this is not the case.
1391.TP
1392.B /etc/ppp/options
1393System default options for pppd, read before user default options or
1394command-line options.
1395.TP
1396.B ~/.ppprc
1397User default options, read before /etc/ppp/options.\fIttyname\fR.
1398.TP
1399.B /etc/ppp/options.\fIttyname
1400System default options for the serial port being used, read after
1401~/.ppprc.  In forming the \fIttyname\fR part of this
1402filename, an initial /dev/ is stripped from the port name (if
1403present), and any slashes in the remaining part are converted to
1404dots.
1405.TP
1406.B /etc/ppp/peers
1407A directory containing options files which may contain privileged
1408options, even if pppd was invoked by a user other than root.  The
1409system administrator can create options files in this directory to
1410permit non-privileged users to dial out without requiring the peer to
1411authenticate, but only to certain trusted peers.
1412.SH SEE ALSO
1413.TP
1414.B RFC1144
1415Jacobson, V.
1416\fICompressing TCP/IP headers for low-speed serial links.\fR
1417February 1990.
1418.TP
1419.B RFC1321
1420Rivest, R.
1421.I The MD5 Message-Digest Algorithm.
1422April 1992.
1423.TP
1424.B RFC1332
1425McGregor, G.
1426.I PPP Internet Protocol Control Protocol (IPCP).
1427May 1992.
1428.TP
1429.B RFC1334
1430Lloyd, B.; Simpson, W.A.
1431.I PPP authentication protocols.
1432October 1992.
1433.TP
1434.B RFC1661
1435Simpson, W.A.
1436.I The Point\-to\-Point Protocol (PPP).
1437July 1994.
1438.TP
1439.B RFC1662
1440Simpson, W.A.
1441.I PPP in HDLC-like Framing.
1442July 1994.
1443.TP
1444.B RFC2472
1445Haskin, D.
1446.I IP Version 6 over PPP
1447December 1998.
1448.SH NOTES
1449The following signals have the specified effect when sent to pppd.
1450.TP
1451.B SIGINT, SIGTERM
1452These signals cause pppd to terminate the link (by closing LCP),
1453restore the serial device settings, and exit.
1454.TP
1455.B SIGHUP
1456This signal causes pppd to terminate the link, restore the serial
1457device settings, and close the serial device.  If the \fIpersist\fR or
1458\fIdemand\fR option has been specified, pppd will try to reopen the
1459serial device and start another connection (after the holdoff period).
1460Otherwise pppd will exit.  If this signal is received during the
1461holdoff period, it causes pppd to end the holdoff period immediately.
1462.TP
1463.B SIGUSR1
1464This signal toggles the state of the \fIdebug\fR option.
1465.TP
1466.B SIGUSR2
1467This signal causes pppd to renegotiate compression.  This can be
1468useful to re-enable compression after it has been disabled as a result
1469of a fatal decompression error.  (Fatal decompression errors generally
1470indicate a bug in one or other implementation.)
1471
1472.SH AUTHORS
1473Paul Mackerras (Paul.Mackerras@cs.anu.edu.au), based on earlier work by
1474Drew Perkins,
1475Brad Clements,
1476Karl Fox,
1477Greg Christy,
1478and
1479Brad Parker.
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