1PPPD(8) System Manager's Manual PPPD(8)
2
6 pppd - Point-to-Point Protocol Daemon
7
9 pppd [ options ]
10
12 PPP is the protocol used for establishing internet links over dial-up
13 modems, DSL connections, and many other types of point-to-point links.
14 The pppd daemon works together with the kernel PPP driver to establish
15 and maintain a PPP link with another system (called the peer) and to
16 negotiate Internet Protocol (IP) addresses for each end of the link.
17 Pppd can also authenticate the peer and/or supply authentication infor‐
18 mation to the peer. PPP can be used with other network protocols be‐
19 sides IP, but such use is becoming increasingly rare.
20
22 ttyname
23 Use the serial port called ttyname to communicate with the peer.
24 If ttyname does not begin with a slash (/), the string "/dev/"
25 is prepended to ttyname to form the name of the device to open.
26 If no device name is given, or if the name of the terminal con‐
27 nected to the standard input is given, pppd will use that termi‐
28 nal, and will not fork to put itself in the background. A value
29 for this option from a privileged source cannot be overridden by
30 a non-privileged user.
31 speed An option that is a decimal number is taken as the desired baud
33 rate for the serial device. On systems such as Linux, 4.4BSD
34 and NetBSD, any speed can be specified. Other systems (e.g.
35 SunOS) only support the commonly-used baud rates.
36 asyncmap map
38 This option sets the Async-Control-Character-Map (ACCM) for this
39 end of the link. The ACCM is a set of 32 bits, one for each of
40 the ASCII control characters with values from 0 to 31, where a 1
41 bit indicates that the corresponding control character should
42 not be used in PPP packets sent to this system. The map is en‐
43 coded as a hexadecimal number (without a leading 0x) where the
44 least significant bit (00000001) represents character 0 and the
45 most significant bit (80000000) represents character 31. Pppd
46 will ask the peer to send these characters as a 2-byte escape
47 sequence. If multiple asyncmap options are given, the values
48 are ORed together. If no asyncmap option is given, the default
49 is zero, so pppd will ask the peer not to escape any control
50 characters. To escape transmitted characters, use the escape
51 option.
52 auth Require the peer to authenticate itself before allowing network
54 packets to be sent or received. This option is the default if
55 the system has a default route. If neither this option nor the
56 noauth option is specified, pppd will only allow the peer to use
57 IP addresses to which the system does not already have a route.
58 call name
60 Read additional options from the file /etc/ppp/peers/name. This
61 file may contain privileged options, such as noauth, even if
62 pppd is not being run by root. The name string may not begin
63 with / or include .. as a pathname component. The format of the
64 options file is described below.
65 connect script
67 Usually there is something which needs to be done to prepare the
68 link before the PPP protocol can be started; for instance, with
69 a dial-up modem, commands need to be sent to the modem to dial
70 the appropriate phone number. This option specifies an command
71 for pppd to execute (by passing it to a shell) before attempting
72 to start PPP negotiation. The chat (8) program is often useful
73 here, as it provides a way to send arbitrary strings to a modem
74 and respond to received characters. A value for this option
75 from a privileged source cannot be overridden by a non-privi‐
76 leged user.
77 crtscts
79 Specifies that pppd should set the serial port to use hardware
80 flow control using the RTS and CTS signals in the RS-232 inter‐
81 face. If neither the crtscts, the nocrtscts, the cdtrcts nor
82 the nocdtrcts option is given, the hardware flow control setting
83 for the serial port is left unchanged. Some serial ports (such
84 as Macintosh serial ports) lack a true RTS output. Such serial
85 ports use this mode to implement unidirectional flow control.
86 The serial port will suspend transmission when requested by the
87 modem (via CTS) but will be unable to request the modem to stop
88 sending to the computer. This mode retains the ability to use
89 DTR as a modem control line.
90 defaultroute
92 Add a default route to the system routing tables, using the peer
93 as the gateway, when IPCP negotiation is successfully completed.
94 This entry is removed when the PPP connection is broken. This
95 option is privileged if the nodefaultroute option has been spec‐
96 ified.
97 defaultroute-metric
99 Define the metric of the defaultroute and only add it if there
100 is no other default route with the same metric. With the de‐
101 fault value of -1, the route is only added if there is no de‐
102 fault route at all.
103 replacedefaultroute
105 This option is a flag to the defaultroute option. If default‐
106 route is set and this flag is also set, pppd replaces an exist‐
107 ing default route with the new default route. This option is
108 privileged.
109 disconnect script
111 Execute the command specified by script, by passing it to a
112 shell, after pppd has terminated the link. This command could,
113 for example, issue commands to the modem to cause it to hang up
114 if hardware modem control signals were not available. The dis‐
115 connect script is not run if the modem has already hung up. A
116 value for this option from a privileged source cannot be over‐
117 ridden by a non-privileged user.
118 escape xx,yy,...
120 Specifies that certain characters should be escaped on transmis‐
121 sion (regardless of whether the peer requests them to be escaped
122 with its async control character map). The characters to be es‐
123 caped are specified as a list of hex numbers separated by com‐
124 mas. Note that almost any character can be specified for the
125 escape option, unlike the asyncmap option which only allows con‐
126 trol characters to be specified. The characters which may not
127 be escaped are those with hex values 0x20 - 0x3f or 0x5e.
128 file name
130 Read options from file name (the format is described below).
131 The file must be readable by the user who has invoked pppd.
132 init script
134 Execute the command specified by script, by passing it to a
135 shell, to initialize the serial line. This script would typi‐
136 cally use the chat(8) program to configure the modem to enable
137 auto answer. A value for this option from a privileged source
138 cannot be overridden by a non-privileged user.
139 lock Specifies that pppd should create a UUCP-style lock file for the
141 serial device to ensure exclusive access to the device. By de‐
142 fault, pppd will not create a lock file.
143 mru n Set the MRU [Maximum Receive Unit] value to n. Pppd will ask the
145 peer to send packets of no more than n bytes. The value of n
146 must be between 128 and 16384; the default is 1500. A value of
147 296 works well on very slow links (40 bytes for TCP/IP header +
148 256 bytes of data). Note that for the IPv6 protocol, the MRU
149 must be at least 1280.
150 mtu n Set the MTU [Maximum Transmit Unit] value to n. Unless the peer
152 requests a smaller value via MRU negotiation, pppd will request
153 that the kernel networking code send data packets of no more
154 than n bytes through the PPP network interface. Note that for
155 the IPv6 protocol, the MTU must be at least 1280.
156 passive
158 Enables the "passive" option in the LCP. With this option, pppd
159 will attempt to initiate a connection; if no reply is received
160 from the peer, pppd will then just wait passively for a valid
161 LCP packet from the peer, instead of exiting, as it would with‐
162 out this option.
163
165 <local_IP_address>:<remote_IP_address>
166 Set the local and/or remote interface IP addresses. Either one
167 may be omitted. The IP addresses can be specified with a host
168 name or in decimal dot notation (e.g. 150.234.56.78). The de‐
169 fault local address is the (first) IP address of the system (un‐
170 less the noipdefault option is given). The remote address will
171 be obtained from the peer if not specified in any option. Thus,
172 in simple cases, this option is not required. If a local and/or
173 remote IP address is specified with this option, pppd will not
174 accept a different value from the peer in the IPCP negotiation,
175 unless the ipcp-accept-local and/or ipcp-accept-remote options
176 are given, respectively.
177 +ipv6 Enable the IPv6CP and IPv6 protocols.
179 ipv6 <local_interface_identifier>,<remote_interface_identifier>
181 Set the local and/or remote 64-bit interface identifier. Either
182 one may be omitted. The identifier must be specified in standard
183 ASCII notation of IPv6 addresses (e.g. ::dead:beef). If the
184 ipv6cp-use-ipaddr option is given, the local identifier is the
185 local IPv4 address and the remote identifier is the remote IPv4
186 address (see above). If the ipv6cp-use-remotenumber option is
187 given, the remote identifier is set to the value from remotenum‐
188 ber option. On systems which supports a unique persistent id,
189 such as EUI-48 derived from the Ethernet MAC address,
190 ipv6cp-use-persistent option can be used to set local identi‐
191 fier. Otherwise both local and remote identifiers are random‐
192 ized.
193 active-filter filter-expression
195 Specifies a packet filter to be applied to data packets to de‐
196 termine which packets are to be regarded as link activity, and
197 therefore reset the idle timer, or cause the link to be brought
198 up in demand-dialling mode. This option is useful in conjunc‐
199 tion with the idle option if there are packets being sent or re‐
200 ceived regularly over the link (for example, routing information
201 packets) which would otherwise prevent the link from ever ap‐
202 pearing to be idle. The filter-expression syntax is as de‐
203 scribed for tcpdump(1), except that qualifiers which are inap‐
204 propriate for a PPP link, such as ether and arp, are not permit‐
205 ted. Generally the filter expression should be enclosed in sin‐
206 gle-quotes to prevent whitespace in the expression from being
207 interpreted by the shell. This option is currently only avail‐
208 able under Linux, and requires that the kernel was configured to
209 include PPP filtering support (CONFIG_PPP_FILTER). Note that it
210 is possible to apply different constraints to incoming and out‐
211 going packets using the inbound and outbound qualifiers.
212 allow-ip address(es)
214 Allow peers to use the given IP address or subnet without au‐
215 thenticating themselves. The parameter is parsed as for each
216 element of the list of allowed IP addresses in the secrets files
217 (see the AUTHENTICATION section below).
218 allow-number number
220 Allow peers to connect from the given telephone number. A
221 trailing `*' character will match all numbers beginning with the
222 leading part.
223 bsdcomp nr,nt
225 Request that the peer compress packets that it sends, using the
226 BSD-Compress scheme, with a maximum code size of nr bits, and
227 agree to compress packets sent to the peer with a maximum code
228 size of nt bits. If nt is not specified, it defaults to the
229 value given for nr. Values in the range 9 to 15 may be used for
230 nr and nt; larger values give better compression but consume
231 more kernel memory for compression dictionaries. Alternatively,
232 a value of 0 for nr or nt disables compression in the corre‐
233 sponding direction. Use nobsdcomp or bsdcomp 0 to disable BSD-
234 Compress compression entirely.
235 ca ca-file
237 (EAP-TLS, or PEAP) Use the file ca-file as the X.509 Certificate
238 Authority (CA) file (in PEM format), needed for setting up an
239 EAP-TLS connection. This option is used on the client-side in
240 conjunction with the cert and key options. Either ca, or capath
241 options are required for PEAP. EAP-TLS may also use the entry in
242 eaptls-client or eaptls-server for a CA certificate associated
243 with a particular peer.
244 capath path
246 (EAP-TLS, or PEAP) Specify a location that contains public CA
247 certificates. Either ca, or capath options are required for
248 PEAP.
249 cdtrcts
251 Use a non-standard hardware flow control (i.e. DTR/CTS) to con‐
252 trol the flow of data on the serial port. If neither the
253 crtscts, the nocrtscts, the cdtrcts nor the nocdtrcts option is
254 given, the hardware flow control setting for the serial port is
255 left unchanged. Some serial ports (such as Macintosh serial
256 ports) lack a true RTS output. Such serial ports use this mode
257 to implement true bi-directional flow control. The sacrifice is
258 that this flow control mode does not permit using DTR as a modem
259 control line.
260 cert certfile
262 (EAP-TLS) Use the file certfile as the X.509 certificate (in PEM
263 format), needed for setting up an EAP-TLS connection. This op‐
264 tion is used on the client-side in conjunction with the ca and
265 key options.
266 chap-interval n
268 If this option is given, pppd will rechallenge the peer every n
269 seconds.
270 chap-max-challenge n
272 Set the maximum number of CHAP challenge transmissions to n (de‐
273 fault 10).
274 chap-restart n
276 Set the CHAP restart interval (retransmission timeout for chal‐
277 lenges) to n seconds (default 3).
278 chap-timeout n
280 Set timeout for CHAP authentication by peer to n seconds (de‐
281 fault 60).
282 chapms-strip-domain
284 Some Windows 9x/ME clients might be transmitting the MS domain
285 before the username in the provided client name. This option en‐
286 ables stripping the domain from the client name on the server
287 side before matching it against the secret file.
288 child-timeout n
290 When exiting, wait for up to n seconds for any child processes
291 (such as the command specified with the pty command) to exit be‐
292 fore exiting. At the end of the timeout, pppd will send a
293 SIGTERM signal to any remaining child processes and exit. A
294 value of 0 means no timeout, that is, pppd will wait until all
295 child processes have exited.
296 connect-delay n
298 Wait for up to n milliseconds after the connect script finishes
299 for a valid PPP packet from the peer. At the end of this time,
300 or when a valid PPP packet is received from the peer, pppd will
301 commence negotiation by sending its first LCP packet. The de‐
302 fault value is 1000 (1 second). This wait period only applies
303 if the connect or pty option is used.
304 crl filename
306 (EAP-TLS, or PEAP) Use the file filename as the Certificate Re‐
307 vocation List to check for the validity of the peer's certifi‐
308 cate. This option is not mandatory for setting up a TLS connec‐
309 tion. Also see the crl-dir option.
310 crl-dir directory
312 (EAP-TLS, or PEAP) Use the directory directory to scan for CRL
313 files in has format ($hash.r0) to check for the validity of the
314 peer's certificate. This option is not mandatory for setting up
315 a TLS connection. Also see the crl option.
316 debug Enables connection debugging facilities. If this option is
318 given, pppd will log the contents of all control packets sent or
319 received in a readable form. The packets are logged through
320 syslog with facility daemon and level debug. This information
321 can be directed to a file by setting up /etc/syslog.conf appro‐
322 priately (see syslog.conf(5)).
323 default-asyncmap
325 Disable asyncmap negotiation, forcing all control characters to
326 be escaped for both the transmit and the receive direction.
327 default-mru
329 Disable MRU [Maximum Receive Unit] negotiation. With this op‐
330 tion, pppd will use the default MRU value of 1500 bytes for both
331 the transmit and receive direction.
332 defaultroute6
334 Add a default IPv6 route to the system routing tables, using the
335 peer as the gateway, when IPv6CP negotiation is successfully
336 completed. This entry is removed when the PPP connection is
337 broken. This option is privileged if the nodefaultroute6 option
338 has been specified. WARNING: Do not enable this option by de‐
339 fault. IPv6 routing tables are managed by kernel (as apposite
340 to IPv4) and IPv6 default route is configured by kernel automat‐
341 ically too based on ICMPv6 Router Advertisement packets. This
342 option may conflict with kernel IPv6 route setup and should be
343 used only for broken IPv6 networks.
344 deflate nr,nt
346 Request that the peer compress packets that it sends, using the
347 Deflate scheme, with a maximum window size of 2**nr bytes, and
348 agree to compress packets sent to the peer with a maximum window
349 size of 2**nt bytes. If nt is not specified, it defaults to the
350 value given for nr. Values in the range 9 to 15 may be used for
351 nr and nt; larger values give better compression but consume
352 more kernel memory for compression dictionaries. Alternatively,
353 a value of 0 for nr or nt disables compression in the corre‐
354 sponding direction. Use nodeflate or deflate 0 to disable De‐
355 flate compression entirely. (Note: pppd requests Deflate com‐
356 pression in preference to BSD-Compress if the peer can do ei‐
357 ther.)
358 demand Initiate the link only on demand, i.e. when data traffic is
360 present. With this option, the remote IP address may be speci‐
361 fied by the user on the command line or in an options file, or
362 if not, pppd will use an arbitrary address in the 10.x.x.x
363 range. Pppd will initially configure the interface and enable
364 it for IP traffic without connecting to the peer. When traffic
365 is available, pppd will connect to the peer and perform negotia‐
366 tion, authentication, etc. When this is completed, pppd will
367 commence passing data packets (i.e., IP packets) across the
368 link.
369 The demand option implies the persist option. If this behaviour
371 is not desired, use the nopersist option after the demand op‐
372 tion. The idle and holdoff options are also useful in conjunc‐
373 tion with the demand option.
374 domain d
376 Append the domain name d to the local host name for authentica‐
377 tion purposes. For example, if gethostname() returns the name
378 porsche, but the fully qualified domain name is
379 porsche.Quotron.COM, you could specify domain Quotron.COM. Pppd
380 would then use the name porsche.Quotron.COM for looking up se‐
381 crets in the secrets file, and as the default name to send to
382 the peer when authenticating itself to the peer. This option is
383 privileged.
384 dryrun With the dryrun option, pppd will print out all the option val‐
386 ues which have been set and then exit, after parsing the command
387 line and options files and checking the option values, but be‐
388 fore initiating the link. The option values are logged at level
389 info, and also printed to standard output unless the device on
390 standard output is the device that pppd would be using to commu‐
391 nicate with the peer.
392 dump With the dump option, pppd will print out all the option values
394 which have been set. This option is like the dryrun option ex‐
395 cept that pppd proceeds as normal rather than exiting.
396 enable-session
398 Enables session accounting via PAM or wtwp/wtmpx, as appropri‐
399 ate. When PAM is enabled, the PAM "account" and "session" mod‐
400 ule stacks determine behavior, and are enabled for all PPP au‐
401 thentication protocols. When PAM is disabled, wtmp/wtmpx en‐
402 tries are recorded regardless of whether the peer name identi‐
403 fies a valid user on the local system, making peers visible in
404 the last(1) log. This feature is automatically enabled when the
405 pppd login option is used. Session accounting is disabled by
406 default.
407 endpoint <epdisc>
409 Sets the endpoint discriminator sent by the local machine to the
410 peer during multilink negotiation to <epdisc>. The default is
411 to use the MAC address of the first ethernet interface on the
412 system, if any, otherwise the IPv4 address corresponding to the
413 hostname, if any, provided it is not in the multicast or lo‐
414 cally-assigned IP address ranges, or the localhost address. The
415 endpoint discriminator can be the string null or of the form
416 type:value, where type is a decimal number or one of the strings
417 local, IP, MAC, magic, or phone. The value is an IP address in
418 dotted-decimal notation for the IP type, or a string of bytes in
419 hexadecimal, separated by periods or colons for the other types.
420 For the MAC type, the value may also be the name of an ethernet
421 or similar network interface. This option is currently only
422 available under Linux.
423 eap-interval n
425 If this option is given and pppd authenticates the peer with EAP
426 (i.e., is the server), pppd will restart EAP authentication ev‐
427 ery n seconds. For EAP SRP-SHA1, see also the srp-interval op‐
428 tion, which enables lightweight rechallenge.
429 eap-max-rreq n
431 Set the maximum number of EAP Requests to which pppd will re‐
432 spond (as a client) without hearing EAP Success or Failure.
433 (Default is 20.)
434 eap-max-sreq n
436 Set the maximum number of EAP Requests that pppd will issue (as
437 a server) while attempting authentication. (Default is 10.)
438 eap-restart n
440 Set the retransmit timeout for EAP Requests when acting as a
441 server (authenticator). (Default is 3 seconds.)
442 eap-timeout n
444 Set the maximum time to wait for the peer to send an EAP Request
445 when acting as a client (authenticatee). (Default is 20 sec‐
446 onds.)
447 hide-password
449 When logging the contents of PAP packets, this option causes
450 pppd to exclude the password string from the log. This is the
451 default.
452 holdoff n
454 Specifies how many seconds to wait before re-initiating the link
455 after it terminates. This option only has any effect if the
456 persist or demand option is used. The holdoff period is not ap‐
457 plied if the link was terminated because it was idle.
458 idle n Specifies that pppd should disconnect if the link is idle for n
460 seconds. The link is idle when no data packets (i.e. IP pack‐
461 ets) are being sent or received. Note: it is not advisable to
462 use this option with the persist option without the demand op‐
463 tion. If the active-filter option is given, data packets which
464 are rejected by the specified activity filter also count as the
465 link being idle.
466 ipcp-accept-local
468 With this option, pppd will accept the peer's idea of our local
469 IP address, even if the local IP address was specified in an op‐
470 tion.
471 ipcp-accept-remote
473 With this option, pppd will accept the peer's idea of its (re‐
474 mote) IP address, even if the remote IP address was specified in
475 an option.
476 ipcp-max-configure n
478 Set the maximum number of IPCP configure-request transmissions
479 to n (default 10).
480 ipcp-max-failure n
482 Set the maximum number of IPCP configure-NAKs returned before
483 starting to send configure-Rejects instead to n (default 10).
484 ipcp-max-terminate n
486 Set the maximum number of IPCP terminate-request transmissions
487 to n (default 3).
488 ipcp-no-address
490 Disable negotiation of addresses via IP-Address IPCP option.
491 ipcp-no-addresses
493 Disable negotiation of addresses via old-style deprecated IP-Ad‐
494 dresses IPCP option. pppd by default try to use new-style IP-Ad‐
495 dress IPCP option. If new-style is not supported by peer or is
496 disabled by ipcp-no-address option then pppd fallbacks to old-
497 style deprecated IP-Addresses IPCP option. When both new-style
498 and old-style are disabled by both ipcp-no-address and
499 ipcp-no-addresses options then negotiation of IP addresses is
500 completely disabled.
501 ipcp-restart n
503 Set the IPCP restart interval (retransmission timeout) to n sec‐
504 onds (default 3).
505 ipparam string
507 Provides an extra parameter most of the notification scripts,
508 most notably ip-up, ip-pre-up, ip-down, ipv6-up, ipv6-down,
509 auth-up and auth-down scripts. If this option is given, the
510 string supplied is given as the 6th parameter to those scripts.
511 ipv6cp-accept-local
513 With this option, pppd will accept the peer's idea of our local
514 IPv6 interface identifier, even if the local IPv6 interface
515 identifier was specified in an option.
516 ipv6cp-accept-remote
518 With this option, pppd will accept the peer's idea of its (re‐
519 mote) IPv6 interface identifier, even if the remote IPv6 inter‐
520 face identifier was specified in an option.
521 ipv6cp-noremote
523 Allow pppd to operate without having an IPv6 link local address
524 for the peer. This option is only available under Linux. Nor‐
525 mally, pppd will request the peer's IPv6 interface identifier
526 (used for composing IPv6 link local address), and if the peer
527 does not supply it, pppd will generate one for the peer. With
528 this option, if the peer does not supply its IPv6 interface
529 identifier, pppd will not ask the peer for it, and will not set
530 the destination IPv6 link local address of the ppp interface.
531 In this situation, the ppp interface can be used for routing by
532 creating device routes, but the peer itself cannot be addressed
533 directly for IPv6 traffic until the peer starts announcing
534 ICMPv6 Router Advertisement or ICMPv6 Neighbor Advertisement
535 packets. Note that IPv6 router must announce ICMPv6 Router Ad‐
536 vertisement packets.
537 ipv6cp-nosendip
539 Don't send our local IPv6 interface identifier to peer during
540 IPv6 interface identifier negotiation.
541 ipv6cp-max-configure n
543 Set the maximum number of IPv6CP configure-request transmissions
544 to n (default 10).
545 ipv6cp-max-failure n
547 Set the maximum number of IPv6CP configure-NAKs returned before
548 starting to send configure-Rejects instead to n (default 10).
549 ipv6cp-max-terminate n
551 Set the maximum number of IPv6CP terminate-request transmissions
552 to n (default 3).
553 ipv6cp-restart n
555 Set the IPv6CP restart interval (retransmission timeout) to n
556 seconds (default 3).
557 kdebug n
559 Enable debugging code in the kernel-level PPP driver. The argu‐
560 ment values depend on the specific kernel driver, but in general
561 a value of 1 will enable general kernel debug messages. (Note
562 that these messages are usually only useful for debugging the
563 kernel driver itself.) For the Linux 2.2.x kernel driver, the
564 value is a sum of bits: 1 to enable general debug messages, 2 to
565 request that the contents of received packets be printed, and 4
566 to request that the contents of transmitted packets be printed.
567 On most systems, messages printed by the kernel are logged by
568 syslog(1) to a file as directed in the /etc/syslog.conf configu‐
569 ration file.
570 key keyfile
572 (EAP-TLS) Use the file keyfile as the private key file (in PEM
573 format), needed for setting up an EAP-TLS connection. This op‐
574 tion is used on the client-side in conjunction with the ca and
575 cert options.
576 ktune Enables pppd to alter kernel settings as appropriate. Under
578 Linux, pppd will enable IP forwarding (i.e. set
579 /proc/sys/net/ipv4/ip_forward to 1) if the proxyarp option is
580 used, and will enable the dynamic IP address option (i.e. set
581 /proc/sys/net/ipv4/ip_dynaddr to 1) in demand mode if the local
582 address changes.
583 lcp-echo-adaptive
585 If this option is used with the lcp-echo-failure option then
586 pppd will send LCP echo-request frames only if no traffic was
587 received from the peer since the last echo-request was sent.
588 lcp-echo-failure n
590 If this option is given, pppd will presume the peer to be dead
591 if n LCP echo-requests are sent without receiving a valid LCP
592 echo-reply. If this happens, pppd will terminate the connec‐
593 tion. Use of this option requires a non-zero value for the
594 lcp-echo-interval parameter. This option can be used to enable
595 pppd to terminate after the physical connection has been broken
596 (e.g., the modem has hung up) in situations where no hardware
597 modem control lines are available.
598 lcp-echo-interval n
600 If this option is given, pppd will send an LCP echo-request
601 frame to the peer every n seconds. Normally the peer should re‐
602 spond to the echo-request by sending an echo-reply. This option
603 can be used with the lcp-echo-failure option to detect that the
604 peer is no longer connected.
605 lcp-max-configure n
607 Set the maximum number of LCP configure-request transmissions to
608 n (default 10).
609 lcp-max-failure n
611 Set the maximum number of LCP configure-NAKs returned before
612 starting to send configure-Rejects instead to n (default 10).
613 lcp-max-terminate n
615 Set the maximum number of LCP terminate-request transmissions to
616 n (default 3).
617 lcp-restart n
619 Set the LCP restart interval (retransmission timeout) to n sec‐
620 onds (default 3).
621 linkname name
623 Sets the logical name of the link to name. Pppd will create a
624 file named ppp-name.pid in /var/run (or /etc/ppp on some sys‐
625 tems) containing its process ID. This can be useful in deter‐
626 mining which instance of pppd is responsible for the link to a
627 given peer system. This is a privileged option.
628 local Don't use the modem control lines. With this option, pppd will
630 ignore the state of the CD (Carrier Detect) signal from the mo‐
631 dem and will not change the state of the DTR (Data Terminal
632 Ready) signal. This is the opposite of the modem option.
633 logfd n
635 Send log messages to file descriptor n. Pppd will send log mes‐
636 sages to at most one file or file descriptor (as well as sending
637 the log messages to syslog), so this option and the logfile op‐
638 tion are mutually exclusive. The default is for pppd to send
639 log messages to stdout (file descriptor 1), unless the serial
640 port is already open on stdout.
641 logfile filename
643 Append log messages to the file filename (as well as sending the
644 log messages to syslog). The file is opened with the privileges
645 of the user who invoked pppd, in append mode.
646 login Use the system password database for authenticating the peer us‐
648 ing PAP, and record the user in the system wtmp file. Note that
649 the peer must have an entry in the /etc/ppp/pap-secrets file as
650 well as the system password database to be allowed access. See
651 also the enable-session option.
652 master_detach
654 If multilink is enabled and this pppd process is the multilink
655 bundle master, and the link controlled by this pppd process ter‐
656 minates, this pppd process continues to run in order to maintain
657 the bundle. If the master_detach option has been given, pppd
658 will detach from its controlling terminal in this situation,
659 even if the nodetach option has been given.
660 maxconnect n
662 Terminate the connection when it has been available for network
663 traffic for n seconds (i.e. n seconds after the first network
664 control protocol comes up).
665 maxfail n
667 Terminate after n consecutive failed connection attempts. A
668 value of 0 means no limit. The default value is 10.
669 max-tls-version string
671 (EAP-TLS, or PEAP) Configures the max allowed TLS version used
672 during negotiation with a peer. The default value for this is
673 1.2. Values allowed for this option is 1.0., 1.1, 1.2, 1.3.
674 modem Use the modem control lines. This option is the default. With
676 this option, pppd will wait for the CD (Carrier Detect) signal
677 from the modem to be asserted when opening the serial device
678 (unless a connect script is specified), and it will drop the DTR
679 (Data Terminal Ready) signal briefly when the connection is ter‐
680 minated and before executing the connect script. On Ultrix,
681 this option implies hardware flow control, as for the crtscts
682 option. This is the opposite of the local option.
683 mp Enables the use of PPP multilink; this is an alias for the `mul‐
685 tilink' option. This option is currently only available under
686 Linux.
687 mppe-stateful
689 Allow MPPE to use stateful mode. Stateless mode is still at‐
690 tempted first. The default is to disallow stateful mode.
691 mpshortseq
693 Enables the use of short (12-bit) sequence numbers in multilink
694 headers, as opposed to 24-bit sequence numbers. This option is
695 only available under Linux, and only has any effect if multilink
696 is enabled (see the multilink option).
697 mrru n Sets the Maximum Reconstructed Receive Unit to n. The MRRU is
699 the maximum size for a received packet on a multilink bundle,
700 and is analogous to the MRU for the individual links. This op‐
701 tion is currently only available under Linux, and only has any
702 effect if multilink is enabled (see the multilink option).
703 ms-dns <addr>
705 If pppd is acting as a server for Microsoft Windows clients,
706 this option allows pppd to supply one or two DNS (Domain Name
707 Server) addresses to the clients. The first instance of this
708 option specifies the primary DNS address; the second instance
709 (if given) specifies the secondary DNS address. (This option
710 was present in some older versions of pppd under the name
711 dns-addr.)
712 ms-wins <addr>
714 If pppd is acting as a server for Microsoft Windows or "Samba"
715 clients, this option allows pppd to supply one or two WINS (Win‐
716 dows Internet Name Services) server addresses to the clients.
717 The first instance of this option specifies the primary WINS ad‐
718 dress; the second instance (if given) specifies the secondary
719 WINS address.
720 multilink
722 Enables the use of the PPP multilink protocol. If the peer also
723 supports multilink, then this link can become part of a bundle
724 between the local system and the peer. If there is an existing
725 bundle to the peer, pppd will join this link to that bundle,
726 otherwise pppd will create a new bundle. See the MULTILINK sec‐
727 tion below. This option is currently only available under
728 Linux.
729 name name
731 Set the name of the local system for authentication purposes to
732 name. This is a privileged option. With this option, pppd will
733 use lines in the secrets files which have name as the second
734 field when looking for a secret to use in authenticating the
735 peer. In addition, unless overridden with the user option, name
736 will be used as the name to send to the peer when authenticating
737 the local system to the peer. (Note that pppd does not append
738 the domain name to name.)
739 noaccomp
741 Disable Address/Control compression in both directions (send and
742 receive).
743 need-peer-eap
745 (EAP-TLS) Require the peer to verify our authentication creden‐
746 tials.
747 noauth Do not require the peer to authenticate itself. This option is
749 privileged.
750 nobsdcomp
752 Disables BSD-Compress compression; pppd will not request or
753 agree to compress packets using the BSD-Compress scheme.
754 noccp Disable CCP (Compression Control Protocol) negotiation. This
756 option should only be required if the peer is buggy and gets
757 confused by requests from pppd for CCP negotiation.
758 nocrtscts
760 Disable hardware flow control (i.e. RTS/CTS) on the serial port.
761 If neither the crtscts nor the nocrtscts nor the cdtrcts nor the
762 nocdtrcts option is given, the hardware flow control setting for
763 the serial port is left unchanged.
764 nocdtrcts
766 This option is a synonym for nocrtscts. Either of these options
767 will disable both forms of hardware flow control.
768 nodefaultroute
770 Disable the defaultroute option. The system administrator who
771 wishes to prevent users from adding a default route with pppd
772 can do so by placing this option in the /etc/ppp/options file.
773 noreplacedefaultroute
775 Disable the replacedefaultroute option. This allows to disable a
776 replacedefaultroute option set previously in the configuration.
777 nodefaultroute6
779 Disable the defaultroute6 option. The system administrator who
780 wishes to prevent users from adding a default route with pppd
781 can do so by placing this option in the /etc/ppp/options file.
782 nodeflate
784 Disables Deflate compression; pppd will not request or agree to
785 compress packets using the Deflate scheme.
786 nodetach
788 Don't detach from the controlling terminal. Without this op‐
789 tion, if a serial device other than the terminal on the standard
790 input is specified, pppd will fork to become a background
791 process.
792 noendpoint
794 Disables pppd from sending an endpoint discriminator to the peer
795 or accepting one from the peer (see the MULTILINK section be‐
796 low). This option should only be required if the peer is buggy.
797 noip Disable IPCP negotiation and IP communication. This option
799 should only be required if the peer is buggy and gets confused
800 by requests from pppd for IPCP negotiation.
801 noipv6 Disable IPv6CP negotiation and IPv6 communication. This option
803 should only be required if the peer is buggy and gets confused
804 by requests from pppd for IPv6CP negotiation.
805 noipdefault
807 Disables the default behaviour when no local IP address is spec‐
808 ified, which is to determine (if possible) the local IP address
809 from the hostname. With this option, the peer will have to sup‐
810 ply the local IP address during IPCP negotiation (unless it
811 specified explicitly on the command line or in an options file).
812 noktune
814 Opposite of the ktune option; disables pppd from changing system
815 settings.
816 nolock Opposite of the lock option; specifies that pppd should not cre‐
818 ate a UUCP-style lock file for the serial device. This option
819 is privileged.
820 nolog Do not send log messages to a file or file descriptor. This op‐
822 tion cancels the logfd and logfile options.
823 nomagic
825 Disable magic number negotiation. With this option, pppd cannot
826 detect a looped-back line. This option should only be needed if
827 the peer is buggy.
828 nomp Disables the use of PPP multilink. This option is currently
830 only available under Linux.
831 nomppe Disables MPPE (Microsoft Point to Point Encryption). This is
833 the default.
834 nomppe-40
836 Disable 40-bit encryption with MPPE.
837 nomppe-128
839 Disable 128-bit encryption with MPPE.
840 nomppe-stateful
842 Disable MPPE stateful mode. This is the default.
843 nompshortseq
845 Disables the use of short (12-bit) sequence numbers in the PPP
846 multilink protocol, forcing the use of 24-bit sequence numbers.
847 This option is currently only available under Linux, and only
848 has any effect if multilink is enabled.
849 nomultilink
851 Disables the use of PPP multilink. This option is currently
852 only available under Linux.
853 nopcomp
855 Disable protocol field compression negotiation in both the re‐
856 ceive and the transmit direction.
857 nopersist
859 Exit once a connection has been made and terminated. This is
860 the default unless the persist or demand option has been speci‐
861 fied.
862 nopredictor1
864 Do not accept or agree to Predictor-1 compression.
865 noproxyarp
867 Disable the proxyarp option. The system administrator who
868 wishes to prevent users from creating proxy ARP entries with
869 pppd can do so by placing this option in the /etc/ppp/options
870 file.
871 noremoteip
873 Allow pppd to operate without having an IP address for the peer.
874 This option is only available under Linux. Normally, pppd will
875 request the peer's IP address, and if the peer does not supply
876 it, pppd will use an arbitrary address in the 10.x.x.x subnet.
877 With this option, if the peer does not supply its IP address,
878 pppd will not ask the peer for it, and will not set the destina‐
879 tion address of the ppp interface. In this situation, the ppp
880 interface can be used for routing by creating device routes, but
881 the peer itself cannot be addressed directly for IP traffic.
882 nosendip
884 Don't send our local IP address to peer during IP address nego‐
885 tiation.
886 notty Normally, pppd requires a terminal device. With this option,
888 pppd will allocate itself a pseudo-tty master/slave pair and use
889 the slave as its terminal device. Pppd will create a child
890 process to act as a `character shunt' to transfer characters be‐
891 tween the pseudo-tty master and its standard input and output.
892 Thus pppd will transmit characters on its standard output and
893 receive characters on its standard input even if they are not
894 terminal devices. This option increases the latency and CPU
895 overhead of transferring data over the ppp interface as all of
896 the characters sent and received must flow through the character
897 shunt process. An explicit device name may not be given if this
898 option is used.
899 novj Disable Van Jacobson style TCP/IP header compression in both the
901 transmit and the receive direction.
902 novjccomp
904 Disable the connection-ID compression option in Van Jacobson
905 style TCP/IP header compression. With this option, pppd will
906 not omit the connection-ID byte from Van Jacobson compressed
907 TCP/IP headers, nor ask the peer to do so.
908 papcrypt
910 Indicates that all secrets in the /etc/ppp/pap-secrets file
911 which are used for checking the identity of the peer are en‐
912 crypted, and thus pppd should not accept a password which, be‐
913 fore encryption, is identical to the secret from the
914 /etc/ppp/pap-secrets file.
915 pap-max-authreq n
917 Set the maximum number of PAP authenticate-request transmissions
918 to n (default 10).
919 pap-restart n
921 Set the PAP restart interval (retransmission timeout) to n sec‐
922 onds (default 3).
923 pap-timeout n
925 Set the maximum time that pppd will wait for the peer to authen‐
926 ticate itself with PAP to n seconds (0 means no limit).
927 pass-filter filter-expression
929 Specifies a packet filter to applied to data packets being sent
930 or received to determine which packets should be allowed to
931 pass. Packets which are rejected by the filter are silently
932 discarded. This option can be used to prevent specific network
933 daemons (such as routed) using up link bandwidth, or to provide
934 a very basic firewall capability. The filter-expression syntax
935 is as described for tcpdump(1), except that qualifiers which are
936 inappropriate for a PPP link, such as ether and arp, are not
937 permitted. Generally the filter expression should be enclosed
938 in single-quotes to prevent whitespace in the expression from
939 being interpreted by the shell. Note that it is possible to ap‐
940 ply different constraints to incoming and outgoing packets using
941 the inbound and outbound qualifiers. This option is currently
942 only available under Linux, and requires that the kernel was
943 configured to include PPP filtering support (CONFIG_PPP_FILTER).
944 password password-string
946 Specifies the password to use for authenticating to the peer.
947 Use of this option is discouraged, as the password is likely to
948 be visible to other users on the system (for example, by using
949 ps(1)).
950 persist
952 Do not exit after a connection is terminated; instead try to re‐
953 open the connection. The maxfail option still has an effect on
954 persistent connections.
955 plugin filename
957 Load the shared library object file filename as a plugin. This
958 is a privileged option. If filename does not contain a slash
959 (/), pppd will look in the /usr/lib/pppd/version directory for
960 the plugin, where version is the version number of pppd (for ex‐
961 ample, 2.4.2).
962 predictor1
964 Request that the peer compress frames that it sends using Pre‐
965 dictor-1 compression, and agree to compress transmitted frames
966 with Predictor-1 if requested. This option has no effect unless
967 the kernel driver supports Predictor-1 compression.
968 privgroup group-name
970 Allows members of group group-name to use privileged options.
971 This is a privileged option. Use of this option requires care
972 as there is no guarantee that members of group-name cannot use
973 pppd to become root themselves. Consider it equivalent to
974 putting the members of group-name in the kmem or disk group.
975 proxyarp
977 Add an entry to this system's ARP [Address Resolution Protocol]
978 table with the IP address of the peer and the Ethernet address
979 of this system. This will have the effect of making the peer
980 appear to other systems to be on the local ethernet.
981 pty script
983 Specifies that the command script is to be used to communicate
984 rather than a specific terminal device. Pppd will allocate it‐
985 self a pseudo-tty master/slave pair and use the slave as its
986 terminal device. The script will be run in a child process with
987 the pseudo-tty master as its standard input and output. An ex‐
988 plicit device name may not be given if this option is used.
989 (Note: if the record option is used in conjunction with the pty
990 option, the child process will have pipes on its standard input
991 and output.)
992 receive-all
994 With this option, pppd will accept all control characters from
995 the peer, including those marked in the receive asyncmap. With‐
996 out this option, pppd will discard those characters as specified
997 in RFC1662. This option should only be needed if the peer is
998 buggy.
999 record filename
1001 Specifies that pppd should record all characters sent and re‐
1002 ceived to a file named filename. This file is opened in append
1003 mode, using the user's user-ID and permissions. This option is
1004 implemented using a pseudo-tty and a process to transfer charac‐
1005 ters between the pseudo-tty and the real serial device, so it
1006 will increase the latency and CPU overhead of transferring data
1007 over the ppp interface. The characters are stored in a tagged
1008 format with timestamps, which can be displayed in readable form
1009 using the pppdump(8) program.
1010 remotename name
1012 Set the assumed name of the remote system for authentication
1013 purposes to name.
1014 remotenumber number
1016 Set the assumed telephone number of the remote system for au‐
1017 thentication purposes to number.
1018 refuse-chap
1020 With this option, pppd will not agree to authenticate itself to
1021 the peer using CHAP.
1022 refuse-mschap
1024 With this option, pppd will not agree to authenticate itself to
1025 the peer using MS-CHAP.
1026 refuse-mschap-v2
1028 With this option, pppd will not agree to authenticate itself to
1029 the peer using MS-CHAPv2.
1030 refuse-eap
1032 With this option, pppd will not agree to authenticate itself to
1033 the peer using EAP.
1034 refuse-pap
1036 With this option, pppd will not agree to authenticate itself to
1037 the peer using PAP.
1038 require-chap
1040 Require the peer to authenticate itself using CHAP [Challenge
1041 Handshake Authentication Protocol] authentication.
1042 require-mppe
1044 Require the use of MPPE (Microsoft Point to Point Encryption).
1045 This option disables all other compression types. This option
1046 enables both 40-bit and 128-bit encryption. In order for MPPE
1047 to successfully come up, you must have authenticated with either
1048 MS-CHAP or MS-CHAPv2. This option is presently only supported
1049 under Linux, and only if your kernel has been configured to in‐
1050 clude MPPE support.
1051 require-mppe-40
1053 Require the use of MPPE, with 40-bit encryption.
1054 require-mppe-128
1056 Require the use of MPPE, with 128-bit encryption.
1057 require-mschap
1059 Require the peer to authenticate itself using MS-CHAP [Microsoft
1060 Challenge Handshake Authentication Protocol] authentication.
1061 require-mschap-v2
1063 Require the peer to authenticate itself using MS-CHAPv2 [Micro‐
1064 soft Challenge Handshake Authentication Protocol, Version 2] au‐
1065 thentication.
1066 require-eap
1068 Require the peer to authenticate itself using EAP [Extensible
1069 Authentication Protocol] authentication.
1070 require-pap
1072 Require the peer to authenticate itself using PAP [Password Au‐
1073 thentication Protocol] authentication.
1074 set name=value
1076 Set an environment variable for scripts that are invoked by
1077 pppd. When set by a privileged source, the variable specified
1078 by name cannot be changed by options contained in an unprivi‐
1079 leged source. See also the unset option and the environment de‐
1080 scribed in SCRIPTS.
1081 show-password
1083 When logging the contents of PAP packets, this option causes
1084 pppd to show the password string in the log message.
1085 silent With this option, pppd will not transmit LCP packets to initiate
1087 a connection until a valid LCP packet is received from the peer
1088 (as for the `passive' option with ancient versions of pppd).
1089 srp-interval n
1091 If this parameter is given and pppd uses EAP SRP-SHA1 to authen‐
1092 ticate the peer (i.e., is the server), then pppd will use the
1093 optional lightweight SRP rechallenge mechanism at intervals of n
1094 seconds. This option is faster than eap-interval reauthentica‐
1095 tion because it uses a hash-based mechanism and does not derive
1096 a new session key.
1097 srp-pn-secret string
1099 Set the long-term pseudonym-generating secret for the server.
1100 This value is optional and if set, needs to be known at the
1101 server (authenticator) side only, and should be different for
1102 each server (or poll of identical servers). It is used along
1103 with the current date to generate a key to encrypt and decrypt
1104 the client's identity contained in the pseudonym.
1105 srp-use-pseudonym
1107 When operating as an EAP SRP-SHA1 client, attempt to use the
1108 pseudonym stored in ~/.ppp_pseudonym first as the identity, and
1109 save in this file any pseudonym offered by the peer during au‐
1110 thentication.
1111 stop-bits n
1113 Set the number of stop bits for the serial port. Valid values
1114 are 1 or 2. The default value is 1.
1115 sync Use synchronous HDLC serial encoding instead of asynchronous.
1117 The device used by pppd with this option must have sync support.
1118 Currently supports Microgate SyncLink adapters under Linux and
1119 FreeBSD 2.2.8 and later.
1120 tls-verify-method string
1122 (EAP-TLS, or PEAP) Match the value specified for remotename to
1123 that that of the X509 certificates subject name, common name, or
1124 suffix of the common name. Respective values allowed for this
1125 option is: none, subject, name, or suffix. The default value
1126 for this option is name.
1127 tls-verify-key-usage
1129 (EAP-TLS, or PEAP) Enables examination of peer certificate's
1130 purpose, and extended key usage attributes.
1131 unit num
1133 Sets the ppp unit number (for a ppp0 or ppp1 etc interface name)
1134 for outbound connections. If the unit is already in use a dy‐
1135 namically allocated number will be used.
1136 ifname string
1138 Set the ppp interface name for outbound connections. If the in‐
1139 terface name is already in use, or if the name cannot be used
1140 for any other reason, pppd will terminate.
1141 unset name
1143 Remove a variable from the environment variable for scripts that
1144 are invoked by pppd. When specified by a privileged source, the
1145 variable name cannot be set by options contained in an unprivi‐
1146 leged source. See also the set option and the environment de‐
1147 scribed in SCRIPTS.
1148 updetach
1150 With this option, pppd will detach from its controlling terminal
1151 once it has successfully established the ppp connection (to the
1152 point where the first network control protocol, usually the IP
1153 control protocol, has come up).
1154 up_sdnotify
1156 Use this option to run pppd in systemd service units of Type=no‐
1157 tify (up_sdnotify implies nodetach). When up_sdnotify is en‐
1158 abled, pppd will notify systemd once it has successfully estab‐
1159 lished the ppp connection (to the point where the first network
1160 control protocl, usually the IP control protocol, has come up).
1161 This option is only availble when pppd is compiled with systemd
1162 support.
1163 usehostname
1165 Enforce the use of the hostname (with domain name appended, if
1166 given) as the name of the local system for authentication pur‐
1167 poses (overrides the name option). This option is not normally
1168 needed since the name option is privileged.
1169 usepeerdns
1171 Ask the peer for up to 2 DNS server addresses. The addresses
1172 supplied by the peer (if any) are passed to the /etc/ppp/ip-up
1173 script in the environment variables DNS1 and DNS2, and the envi‐
1174 ronment variable USEPEERDNS will be set to 1. In addition, pppd
1175 will create an /etc/ppp/resolv.conf file containing one or two
1176 nameserver lines with the address(es) supplied by the peer.
1177 usepeerwins
1179 Ask the peer for up to 2 WINS server addresses. The addresses
1180 supplied by the peer (if any) are passed to the /etc/ppp/ip-up
1181 script in the environment variables WINS1 and WINS2, and the en‐
1182 vironment variable USEPEERWINS will be set to 1.
1183 Please note that some modems (like the Huawei E220) requires this op‐
1185 tion in order to avoid a race condition that results in the incorrect
1186 DNS servers being assigned.
1187 user name
1189 Sets the name used for authenticating the local system to the
1190 peer to name.
1191 vj-max-slots n
1193 Sets the number of connection slots to be used by the Van Jacob‐
1194 son TCP/IP header compression and decompression code to n, which
1195 must be between 2 and 16 (inclusive).
1196 welcome script
1198 Run the executable or shell command specified by script before
1199 initiating PPP negotiation, after the connect script (if any)
1200 has completed. A value for this option from a privileged source
1201 cannot be overridden by a non-privileged user.
1202 xonxoff
1204 Use software flow control (i.e. XON/XOFF) to control the flow of
1205 data on the serial port.
1206
1208 To establish PPP link over Ethernet (PPPoE) it is needed to load pppd's
1209 plugin pppoe.so and then specify option nic-interface instead of modem
1210 options ttyname and speed. Recognized pppd's PPPoE options are:
1211 nic-interface
1213 Use the ethernet device interface to communicate with the peer.
1214 For example, establishing PPPoE link on eth0 interface is done
1215 by specifying ppp'd option nic-eth0. Prefix nic- for this option
1216 may be avoided if interface name is unambiguous and does not
1217 look like any other pppd's option.
1218 pppoe-service name
1220 Connect to specified PPPoE service name. For backward compati‐
1221 bility also rp_pppoe_service option name is supported.
1222 pppoe-ac name
1224 Connect to specified PPPoE access concentrator name. For back‐
1225 ward compatibility also rp_pppoe_ac option name is supported.
1226 pppoe-sess sessid:macaddr
1228 Attach to existing PPPoE session. For backward compatibility
1229 also rp_pppoe_sess option name is supported.
1230 pppoe-verbose n
1232 Be verbose about discovered access concentrators. When set to 2
1233 or bigger value then dump also discovery packets. For backward
1234 compatibility also rp_pppoe_verbose option name is supported.
1235 pppoe-mac macaddr
1237 Connect to specified MAC address.
1238 pppoe-host-uniq string
1240 Set the PPPoE Host-Uniq tag to the supplied hex string. By de‐
1241 fault PPPoE Host-Uniq tag is set to the pppd's process PID. For
1242 backward compatibility this option may be specified without pp‐
1243 poe- prefix.
1244 pppoe-padi-timeout n
1246 Initial timeout for discovery packets in seconds (default 5).
1247 pppoe-padi-attempts n
1249 Number of discovery attempts (default 3).
1250
1252 Options can be taken from files as well as the command line. Pppd
1253 reads options from the files /etc/ppp/options, ~/.ppprc and
1254 /etc/ppp/options.ttyname (in that order) before processing the options
1255 on the command line. (In fact, the command-line options are scanned to
1256 find the terminal name before the options.ttyname file is read.) In
1257 forming the name of the options.ttyname file, the initial /dev/ is re‐
1258 moved from the terminal name, and any remaining / characters are re‐
1259 placed with dots.
1260 An options file is parsed into a series of words, delimited by white‐
1262 space. Whitespace can be included in a word by enclosing the word in
1263 double-quotes ("). A backslash (\) quotes the following character. A
1264 hash (#) starts a comment, which continues until the end of the line.
1265 There is no restriction on using the file or call options within an op‐
1266 tions file.
1267
1269 pppd provides system administrators with sufficient access control that
1270 PPP access to a server machine can be provided to legitimate users
1271 without fear of compromising the security of the server or the network
1272 it's on. This control is provided through restrictions on which IP ad‐
1273 dresses the peer may use, based on its authenticated identity (if any),
1274 and through restrictions on which options a non-privileged user may
1275 use. Several of pppd's options are privileged, in particular those
1276 which permit potentially insecure configurations; these options are
1277 only accepted in files which are under the control of the system admin‐
1278 istrator, or if pppd is being run by root.
1279 The default behaviour of pppd is to allow an unauthenticated peer to
1281 use a given IP address only if the system does not already have a route
1282 to that IP address. For example, a system with a permanent connection
1283 to the wider internet will normally have a default route, and thus all
1284 peers will have to authenticate themselves in order to set up a connec‐
1285 tion. On such a system, the auth option is the default. On the other
1286 hand, a system where the PPP link is the only connection to the inter‐
1287 net will not normally have a default route, so the peer will be able to
1288 use almost any IP address without authenticating itself.
1289 As indicated above, some security-sensitive options are privileged,
1291 which means that they may not be used by an ordinary non-privileged
1292 user running a setuid-root pppd, either on the command line, in the
1293 user's ~/.ppprc file, or in an options file read using the file option.
1294 Privileged options may be used in /etc/ppp/options file or in an op‐
1295 tions file read using the call option. If pppd is being run by the
1296 root user, privileged options can be used without restriction.
1297 When opening the device, pppd uses either the invoking user's user ID
1299 or the root UID (that is, 0), depending on whether the device name was
1300 specified by the user or the system administrator. If the device name
1301 comes from a privileged source, that is, /etc/ppp/options or an options
1302 file read using the call option, pppd uses full root privileges when
1303 opening the device. Thus, by creating an appropriate file under
1304 /etc/ppp/peers, the system administrator can allow users to establish a
1305 ppp connection via a device which they would not normally have permis‐
1306 sion to access. Otherwise pppd uses the invoking user's real UID when
1307 opening the device.
1308
1310 Authentication is the process whereby one peer convinces the other of
1311 its identity. This involves the first peer sending its name to the
1312 other, together with some kind of secret information which could only
1313 come from the genuine authorized user of that name. In such an ex‐
1314 change, we will call the first peer the "client" and the other the
1315 "server". The client has a name by which it identifies itself to the
1316 server, and the server also has a name by which it identifies itself to
1317 the client. Generally the genuine client shares some secret (or pass‐
1318 word) with the server, and authenticates itself by proving that it
1319 knows that secret. Very often, the names used for authentication cor‐
1320 respond to the internet hostnames of the peers, but this is not essen‐
1321 tial.
1322 At present, pppd supports three authentication protocols: the Password
1324 Authentication Protocol (PAP), Challenge Handshake Authentication Pro‐
1325 tocol (CHAP), and Extensible Authentication Protocol (EAP). PAP in‐
1326 volves the client sending its name and a cleartext password to the
1327 server to authenticate itself. In contrast, the server initiates the
1328 CHAP authentication exchange by sending a challenge to the client (the
1329 challenge packet includes the server's name). The client must respond
1330 with a response which includes its name plus a hash value derived from
1331 the shared secret and the challenge, in order to prove that it knows
1332 the secret. EAP supports CHAP-style authentication, and also includes
1333 the SRP-SHA1 mechanism, which is resistant to dictionary-based attacks
1334 and does not require a cleartext password on the server side.
1335 The PPP protocol, being symmetrical, allows both peers to require the
1337 other to authenticate itself. In that case, two separate and indepen‐
1338 dent authentication exchanges will occur. The two exchanges could use
1339 different authentication protocols, and in principle, different names
1340 could be used in the two exchanges.
1341 The default behaviour of pppd is to agree to authenticate if requested,
1343 and to not require authentication from the peer. However, pppd will
1344 not agree to authenticate itself with a particular protocol if it has
1345 no secrets which could be used to do so.
1346 Pppd stores secrets for use in authentication in secrets files
1348 (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP, MS-CHAP,
1349 MS-CHAPv2, and EAP MD5-Challenge, and /etc/ppp/srp-secrets for EAP
1350 SRP-SHA1). All secrets files have the same format. The secrets files
1351 can contain secrets for pppd to use in authenticating itself to other
1352 systems, as well as secrets for pppd to use when authenticating other
1353 systems to itself.
1354 Each line in a secrets file contains one secret. A given secret is
1356 specific to a particular combination of client and server - it can only
1357 be used by that client to authenticate itself to that server. Thus
1358 each line in a secrets file has at least 3 fields: the name of the
1359 client, the name of the server, and the secret. These fields may be
1360 followed by a list of the IP addresses that the specified client may
1361 use when connecting to the specified server.
1362 A secrets file is parsed into words as for a options file, so the
1364 client name, server name and secrets fields must each be one word, with
1365 any embedded spaces or other special characters quoted or escaped.
1366 Note that case is significant in the client and server names and in the
1367 secret.
1368 If the secret starts with an `@', what follows is assumed to be the
1370 name of a file from which to read the secret. A "*" as the client or
1371 server name matches any name. When selecting a secret, pppd takes the
1372 best match, i.e. the match with the fewest wildcards.
1373 Any following words on the same line are taken to be a list of accept‐
1375 able IP addresses for that client. If there are only 3 words on the
1376 line, or if the first word is "-", then all IP addresses are disal‐
1377 lowed. To allow any address, use "*". A word starting with "!" indi‐
1378 cates that the specified address is not acceptable. An address may be
1379 followed by "/" and a number n, to indicate a whole subnet, i.e. all
1380 addresses which have the same value in the most significant n bits. In
1381 this form, the address may be followed by a plus sign ("+") to indicate
1382 that one address from the subnet is authorized, based on the ppp net‐
1383 work interface unit number in use. In this case, the host part of the
1384 address will be set to the unit number plus one.
1385 Thus a secrets file contains both secrets for use in authenticating
1387 other hosts, plus secrets which we use for authenticating ourselves to
1388 others. When pppd is authenticating the peer (checking the peer's
1389 identity), it chooses a secret with the peer's name in the first field
1390 and the name of the local system in the second field. The name of the
1391 local system defaults to the hostname, with the domain name appended if
1392 the domain option is used. This default can be overridden with the
1393 name option, except when the usehostname option is used. (For EAP
1394 SRP-SHA1, see the srp-entry(8) utility for generating proper validator
1395 entries to be used in the "secret" field.)
1396 When pppd is choosing a secret to use in authenticating itself to the
1398 peer, it first determines what name it is going to use to identify it‐
1399 self to the peer. This name can be specified by the user with the user
1400 option. If this option is not used, the name defaults to the name of
1401 the local system, determined as described in the previous paragraph.
1402 Then pppd looks for a secret with this name in the first field and the
1403 peer's name in the second field. Pppd will know the name of the peer
1404 if CHAP or EAP authentication is being used, because the peer will have
1405 sent it in the challenge packet. However, if PAP is being used, pppd
1406 will have to determine the peer's name from the options specified by
1407 the user. The user can specify the peer's name directly with the re‐
1408 motename option. Otherwise, if the remote IP address was specified by
1409 a name (rather than in numeric form), that name will be used as the
1410 peer's name. Failing that, pppd will use the null string as the peer's
1411 name.
1412 When authenticating the peer with PAP, the supplied password is first
1414 compared with the secret from the secrets file. If the password
1415 doesn't match the secret, the password is encrypted using crypt() and
1416 checked against the secret again. Thus secrets for authenticating the
1417 peer can be stored in encrypted form if desired. If the papcrypt op‐
1418 tion is given, the first (unencrypted) comparison is omitted, for bet‐
1419 ter security.
1420 Furthermore, if the login option was specified, the username and pass‐
1422 word are also checked against the system password database. Thus, the
1423 system administrator can set up the pap-secrets file to allow PPP ac‐
1424 cess only to certain users, and to restrict the set of IP addresses
1425 that each user can use. Typically, when using the login option, the
1426 secret in /etc/ppp/pap-secrets would be "", which will match any pass‐
1427 word supplied by the peer. This avoids the need to have the same se‐
1428 cret in two places.
1429 Authentication must be satisfactorily completed before IPCP (or any
1431 other Network Control Protocol) can be started. If the peer is re‐
1432 quired to authenticate itself, and fails to do so, pppd will terminated
1433 the link (by closing LCP). If IPCP negotiates an unacceptable IP ad‐
1434 dress for the remote host, IPCP will be closed. IP packets can only be
1435 sent or received when IPCP is open.
1436 In some cases it is desirable to allow some hosts which can't authenti‐
1438 cate themselves to connect and use one of a restricted set of IP ad‐
1439 dresses, even when the local host generally requires authentication.
1440 If the peer refuses to authenticate itself when requested, pppd takes
1441 that as equivalent to authenticating with PAP using the empty string
1442 for the username and password. Thus, by adding a line to the pap-se‐
1443 crets file which specifies the empty string for the client and pass‐
1444 word, it is possible to allow restricted access to hosts which refuse
1445 to authenticate themselves.
1446
1448 When IPCP negotiation is completed successfully, pppd will inform the
1449 kernel of the local and remote IP addresses for the ppp interface.
1450 This is sufficient to create a host route to the remote end of the
1451 link, which will enable the peers to exchange IP packets. Communica‐
1452 tion with other machines generally requires further modification to
1453 routing tables and/or ARP (Address Resolution Protocol) tables. In
1454 most cases the defaultroute and/or proxyarp options are sufficient for
1455 this, but in some cases further intervention is required. The
1456 /etc/ppp/ip-up script can be used for this.
1457 Sometimes it is desirable to add a default route through the remote
1459 host, as in the case of a machine whose only connection to the Internet
1460 is through the ppp interface. The defaultroute option causes pppd to
1461 create such a default route when IPCP comes up, and delete it when the
1462 link is terminated.
1463 In some cases it is desirable to use proxy ARP, for example on a server
1465 machine connected to a LAN, in order to allow other hosts to communi‐
1466 cate with the remote host. The proxyarp option causes pppd to look for
1467 a network interface on the same subnet as the remote host (an interface
1468 supporting broadcast and ARP, which is up and not a point-to-point or
1469 loopback interface). If found, pppd creates a permanent, published ARP
1470 entry with the IP address of the remote host and the hardware address
1471 of the network interface found.
1472 When the demand option is used, the interface IP addresses have already
1474 been set at the point when IPCP comes up. If pppd has not been able to
1475 negotiate the same addresses that it used to configure the interface
1476 (for example when the peer is an ISP that uses dynamic IP address as‐
1477 signment), pppd has to change the interface IP addresses to the negoti‐
1478 ated addresses. This may disrupt existing connections, and the use of
1479 demand dialling with peers that do dynamic IP address assignment is not
1480 recommended.
1481
1483 Multilink PPP provides the capability to combine two or more PPP links
1484 between a pair of machines into a single `bundle', which appears as a
1485 single virtual PPP link which has the combined bandwidth of the indi‐
1486 vidual links. Currently, multilink PPP is only supported under Linux.
1487 Pppd detects that the link it is controlling is connected to the same
1489 peer as another link using the peer's endpoint discriminator and the
1490 authenticated identity of the peer (if it authenticates itself). The
1491 endpoint discriminator is a block of data which is hopefully unique for
1492 each peer. Several types of data can be used, including locally-as‐
1493 signed strings of bytes, IP addresses, MAC addresses, randomly strings
1494 of bytes, or E-164 phone numbers. The endpoint discriminator sent to
1495 the peer by pppd can be set using the endpoint option.
1496 In some circumstances the peer may send no endpoint discriminator or a
1498 non-unique value. The bundle option adds an extra string which is
1499 added to the peer's endpoint discriminator and authenticated identity
1500 when matching up links to be joined together in a bundle. The bundle
1501 option can also be used to allow the establishment of multiple bundles
1502 between the local system and the peer. Pppd uses a TDB database in
1503 /var/run/pppd2.tdb to match up links.
1504 Assuming that multilink is enabled and the peer is willing to negotiate
1506 multilink, then when pppd is invoked to bring up the first link to the
1507 peer, it will detect that no other link is connected to the peer and
1508 create a new bundle, that is, another ppp network interface unit. When
1509 another pppd is invoked to bring up another link to the peer, it will
1510 detect the existing bundle and join its link to it.
1511 If the first link terminates (for example, because of a hangup or a re‐
1513 ceived LCP terminate-request) the bundle is not destroyed unless there
1514 are no other links remaining in the bundle. Rather than exiting, the
1515 first pppd keeps running after its link terminates, until all the links
1516 in the bundle have terminated. If the first pppd receives a SIGTERM or
1517 SIGINT signal, it will destroy the bundle and send a SIGHUP to the pppd
1518 processes for each of the links in the bundle. If the first pppd re‐
1519 ceives a SIGHUP signal, it will terminate its link but not the bundle.
1520 Note: demand mode is not currently supported with multilink.
1522
1524 The following examples assume that the /etc/ppp/options file contains
1525 the auth option (as in the default /etc/ppp/options file in the ppp
1526 distribution).
1527 Probably the most common use of pppd is to dial out to an ISP. This
1529 can be done with a command such as
1530 pppd call isp
1532 where the /etc/ppp/peers/isp file is set up by the system administrator
1534 to contain something like this:
1535 ttyS0 19200 crtscts
1537 connect '/usr/sbin/chat -v -f /etc/ppp/chat-isp'
1538 noauth
1539 In this example, we are using chat to dial the ISP's modem and go
1541 through any logon sequence required. The /etc/ppp/chat-isp file con‐
1542 tains the script used by chat; it could for example contain something
1543 like this:
1544 ABORT "NO CARRIER"
1546 ABORT "NO DIALTONE"
1547 ABORT "ERROR"
1548 ABORT "NO ANSWER"
1549 ABORT "BUSY"
1550 ABORT "Username/Password Incorrect"
1551 "" "at"
1552 OK "at&d0&c1"
1553 OK "atdt2468135"
1554 "name:" "^Umyuserid"
1555 "word:" "\qmypassword"
1556 "ispts" "\q^Uppp"
1557 "~-^Uppp-~"
1558 See the chat(8) man page for details of chat scripts.
1560 Pppd can also be used to provide a dial-in ppp service for users. If
1562 the users already have login accounts, the simplest way to set up the
1563 ppp service is to let the users log in to their accounts and run pppd
1564 (installed setuid-root) with a command such as
1565 pppd proxyarp
1567 To allow a user to use the PPP facilities, you need to allocate an IP
1569 address for that user's machine and create an entry in /etc/ppp/pap-se‐
1570 crets, /etc/ppp/chap-secrets, or /etc/ppp/srp-secrets (depending on
1571 which authentication method the PPP implementation on the user's ma‐
1572 chine supports), so that the user's machine can authenticate itself.
1573 For example, if Joe has a machine called "joespc" that is to be allowed
1574 to dial in to the machine called "server" and use the IP address joe‐
1575 spc.my.net, you would add an entry like this to /etc/ppp/pap-secrets or
1576 /etc/ppp/chap-secrets:
1577 joespc server "joe's secret" joespc.my.net
1579 (See srp-entry(8) for a means to generate the server's entry when
1581 SRP-SHA1 is in use.) Alternatively, you can create a username called
1582 (for example) "ppp", whose login shell is pppd and whose home directory
1583 is /etc/ppp. Options to be used when pppd is run this way can be put
1584 in /etc/ppp/.ppprc.
1585 If your serial connection is any more complicated than a piece of wire,
1587 you may need to arrange for some control characters to be escaped. In
1588 particular, it is often useful to escape XON (^Q) and XOFF (^S), using
1589 asyncmap a0000. If the path includes a telnet, you probably should es‐
1590 cape ^] as well (asyncmap 200a0000). If the path includes an rlogin,
1591 you will need to use the escape ff option on the end which is running
1592 the rlogin client, since many rlogin implementations are not transpar‐
1593 ent; they will remove the sequence [0xff, 0xff, 0x73, 0x73, followed by
1594 any 8 bytes] from the stream.
1595
1597 Messages are sent to the syslog daemon using facility LOG_DAEMON.
1598 (This can be overridden by recompiling pppd with the macro LOG_PPP de‐
1599 fined as the desired facility.) See the syslog(8) documentation for
1600 details of where the syslog daemon will write the messages. On most
1601 systems, the syslog daemon uses the /etc/syslog.conf file to specify
1602 the destination(s) for syslog messages. You may need to edit that file
1603 to suit.
1604 The debug option causes the contents of all control packets sent or re‐
1606 ceived to be logged, that is, all LCP, PAP, CHAP, EAP, or IPCP packets.
1607 This can be useful if the PPP negotiation does not succeed or if au‐
1608 thentication fails. If debugging is enabled at compile time, the debug
1609 option also causes other debugging messages to be logged.
1610 Debugging can also be enabled or disabled by sending a SIGUSR1 signal
1612 to the pppd process. This signal acts as a toggle.
1613
1615 The exit status of pppd is set to indicate whether any error was de‐
1616 tected, or the reason for the link being terminated. The values used
1617 are:
1618 0 Pppd has detached, or otherwise the connection was successfully
1620 established and terminated at the peer's request.
1621 1 An immediately fatal error of some kind occurred, such as an es‐
1623 sential system call failing, or running out of virtual memory.
1624 2 An error was detected in processing the options given, such as
1626 two mutually exclusive options being used.
1627 3 Pppd is not setuid-root and the invoking user is not root.
1629 4 The kernel does not support PPP, for example, the PPP kernel
1631 driver is not included or cannot be loaded.
1632 5 Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP
1634 signal.
1635 6 The serial port could not be locked.
1637 7 The serial port could not be opened.
1639 8 The connect script failed (returned a non-zero exit status).
1641 9 The command specified as the argument to the pty option could
1643 not be run.
1644 10 The PPP negotiation failed, that is, it didn't reach the point
1646 where at least one network protocol (e.g. IP) was running.
1647 11 The peer system failed (or refused) to authenticate itself.
1649 12 The link was established successfully and terminated because it
1651 was idle.
1652 13 The link was established successfully and terminated because the
1654 connect time limit was reached.
1655 14 Callback was negotiated and an incoming call should arrive
1657 shortly.
1658 15 The link was terminated because the peer is not responding to
1660 echo requests.
1661 16 The link was terminated by the modem hanging up.
1663 17 The PPP negotiation failed because serial loopback was detected.
1665 18 The init script failed (returned a non-zero exit status).
1667 19 We failed to authenticate ourselves to the peer.
1669
1671 Pppd invokes scripts at various stages in its processing which can be
1672 used to perform site-specific ancillary processing. These scripts are
1673 usually shell scripts, but could be executable code files instead.
1674 Pppd does not wait for the scripts to finish (except for the ip-pre-up
1675 script). The scripts are executed as root (with the real and effective
1676 user-id set to 0), so that they can do things such as update routing
1677 tables or run privileged daemons. Be careful that the contents of
1678 these scripts do not compromise your system's security. Pppd runs the
1679 scripts with standard input, output and error redirected to /dev/null,
1680 and with an environment that is empty except for some environment vari‐
1681 ables that give information about the link. The environment variables
1682 that pppd sets are:
1683 DEVICE The name of the serial tty device being used.
1685 IFNAME The name of the network interface being used.
1687 IPLOCAL
1689 The IP address for the local end of the link. This is only set
1690 when IPCP has come up.
1691 IPREMOTE
1693 The IP address for the remote end of the link. This is only set
1694 when IPCP has come up.
1695 LLLOCAL
1697 The Link-Local IPv6 address for the local end of the link. This
1698 is only set when IPV6CP has come up.
1699 LLREMOTE
1701 The Link-Local IPv6 address for the remote end of the link.
1702 This is only set when IPV6CP has come up.
1703 PEERNAME
1705 The authenticated name of the peer. This is only set if the
1706 peer authenticates itself.
1707 SPEED The baud rate of the tty device.
1709 ORIG_UID
1711 The real user-id of the user who invoked pppd.
1712 PPPLOGNAME
1714 The username of the real user-id that invoked pppd. This is al‐
1715 ways set.
1716 For the ip-down and auth-down scripts, pppd also sets the following
1718 variables giving statistics for the connection:
1719 CONNECT_TIME
1721 The number of seconds from when the PPP negotiation started un‐
1722 til the connection was terminated.
1723 BYTES_SENT
1725 The number of bytes sent (at the level of the serial port) dur‐
1726 ing the connection.
1727 BYTES_RCVD
1729 The number of bytes received (at the level of the serial port)
1730 during the connection.
1731 LINKNAME
1733 The logical name of the link, set with the linkname option.
1734 CALL_FILE
1736 The value of the call option.
1737 DNS1 If the peer supplies DNS server addresses, this variable is set
1739 to the first DNS server address supplied (whether or not the
1740 usepeerdns option was given).
1741 DNS2 If the peer supplies DNS server addresses, this variable is set
1743 to the second DNS server address supplied (whether or not the
1744 usepeerdns option was given).
1745 WINS1 If the peer supplies WINS server addresses, this variable is set
1747 to the first WINS server address supplied.
1748 WINS2 If the peer supplies WINS server addresses, this variable is set
1750 to the second WINS server address supplied.
1751 Pppd invokes the following scripts, if they exist. It is not an error
1753 if they don't exist.
1754 /etc/ppp/auth-up
1756 A program or script which is executed after the remote system
1757 successfully authenticates itself. It is executed with the pa‐
1758 rameters
1759 interface-name peer-name user-name tty-device speed ipparam
1761 Note that this script is not executed if the peer doesn't au‐
1763 thenticate itself, for example when the noauth option is used.
1764 /etc/ppp/auth-down
1766 A program or script which is executed when the link goes down,
1767 if /etc/ppp/auth-up was previously executed. It is executed in
1768 the same manner with the same parameters as /etc/ppp/auth-up.
1769 /etc/ppp/ip-pre-up
1771 A program or script which is executed just before the ppp net‐
1772 work interface is brought up. It is executed with the same pa‐
1773 rameters as the ip-up script (below). At this point the inter‐
1774 face exists and has IP addresses assigned but is still down.
1775 This can be used to add firewall rules before any IP traffic can
1776 pass through the interface. Pppd will wait for this script to
1777 finish before bringing the interface up, so this script should
1778 run quickly.
1779 /etc/ppp/ip-up
1781 A program or script which is executed when the link is available
1782 for sending and receiving IP packets (that is, IPCP has come
1783 up). It is executed with the parameters
1784 interface-name tty-device speed local-IP-address remote-IP-ad‐
1786 dress ipparam
1787 /etc/ppp/ip-down
1789 A program or script which is executed when the link is no longer
1790 available for sending and receiving IP packets. This script can
1791 be used for undoing the effects of the /etc/ppp/ip-up and
1792 /etc/ppp/ip-pre-up scripts. It is invoked in the same manner
1793 and with the same parameters as the ip-up script.
1794 /etc/ppp/ipv6-up
1796 Like /etc/ppp/ip-up, except that it is executed when the link is
1797 available for sending and receiving IPv6 packets. It is executed
1798 with the parameters
1799 interface-name tty-device speed local-link-local-address re‐
1801 mote-link-local-address ipparam
1802 /etc/ppp/ipv6-down
1804 Similar to /etc/ppp/ip-down, but it is executed when IPv6 pack‐
1805 ets can no longer be transmitted on the link. It is executed
1806 with the same parameters as the ipv6-up script.
1807 /var/run/pppn.pid (BSD or Linux), /etc/ppp/pppn.pid (others)
1809 Process-ID for pppd process on ppp interface unit n.
1810 /var/run/ppp-name.pid (BSD or Linux),
1812 /etc/ppp/ppp-name.pid (others) Process-ID for pppd process for
1813 logical link name (see the linkname option).
1814 /var/run/pppd2.tdb
1816 Database containing information about pppd processes, interfaces
1817 and links, used for matching links to bundles in multilink oper‐
1818 ation. May be examined by external programs to obtain informa‐
1819 tion about running pppd instances, the interfaces and devices
1820 they are using, IP address assignments, etc. /etc/ppp/pap-se‐
1821 crets Usernames, passwords and IP addresses for PAP authentica‐
1822 tion. This file should be owned by root and not readable or
1823 writable by any other user. Pppd will log a warning if this is
1824 not the case.
1825 /etc/ppp/chap-secrets
1827 Names, secrets and IP addresses for CHAP/MS-CHAP/MS-CHAPv2 au‐
1828 thentication. As for /etc/ppp/pap-secrets, this file should be
1829 owned by root and not readable or writable by any other user.
1830 Pppd will log a warning if this is not the case.
1831 /etc/ppp/srp-secrets
1833 Names, secrets, and IP addresses for EAP authentication. As for
1834 /etc/ppp/pap-secrets, this file should be owned by root and not
1835 readable or writable by any other user. Pppd will log a warning
1836 if this is not the case.
1837 ~/.ppp_pseudonym
1839 Saved client-side SRP-SHA1 pseudonym. See the srp-use-pseudonym
1840 option for details.
1841 /etc/ppp/options
1843 System default options for pppd, read before user default op‐
1844 tions or command-line options.
1845 ~/.ppprc
1847 User default options, read before /etc/ppp/options.ttyname.
1848 /etc/ppp/options.ttyname
1850 System default options for the serial port being used, read af‐
1851 ter ~/.ppprc. In forming the ttyname part of this filename, an
1852 initial /dev/ is stripped from the port name (if present), and
1853 any slashes in the remaining part are converted to dots.
1854 /etc/ppp/peers
1856 A directory containing options files which may contain privi‐
1857 leged options, even if pppd was invoked by a user other than
1858 root. The system administrator can create options files in this
1859 directory to permit non-privileged users to dial out without re‐
1860 quiring the peer to authenticate, but only to certain trusted
1861 peers.
1862
1864 chat(8), pppstats(8)
1865 RFC1144
1867 Jacobson, V. Compressing TCP/IP headers for low-speed serial
1868 links. February 1990.
1869 RFC1321
1871 Rivest, R. The MD5 Message-Digest Algorithm. April 1992.
1872 RFC1332
1874 McGregor, G. PPP Internet Protocol Control Protocol (IPCP).
1875 May 1992.
1876 RFC1334
1878 Lloyd, B.; Simpson, W.A. PPP authentication protocols. October
1879 1992.
1880 RFC1661
1882 Simpson, W.A. The Point-to-Point Protocol (PPP). July 1994.
1883 RFC1662
1885 Simpson, W.A. PPP in HDLC-like Framing. July 1994.
1886 RFC1990
1888 Sklower, K.; et al., The PPP Multilink Protocol (MP). August
1889 1996.
1890 RFC2284
1892 Blunk, L.; Vollbrecht, J., PPP Extensible Authentication Proto‐
1893 col (EAP). March 1998.
1894 RFC2472
1896 Haskin, D. IP Version 6 over PPP December 1998.
1897 RFC2945
1899 Wu, T., The SRP Authentication and Key Exchange System September
1900 2000.
1901 draft-ietf-pppext-eap-srp-03.txt
1903 Carlson, J.; et al., EAP SRP-SHA1 Authentication Protocol. July
1904 2001.
1905
1907 Some limited degree of control can be exercised over a running pppd
1908 process by sending it a signal from the list below.
1909 SIGINT, SIGTERM
1911 These signals cause pppd to terminate the link (by closing LCP),
1912 restore the serial device settings, and exit. If a connector or
1913 disconnector process is currently running, pppd will send the
1914 same signal to its process group, so as to terminate the connec‐
1915 tor or disconnector process.
1916 SIGHUP This signal causes pppd to terminate the link, restore the se‐
1918 rial device settings, and close the serial device. If the per‐
1919 sist or demand option has been specified, pppd will try to re‐
1920 open the serial device and start another connection (after the
1921 holdoff period). Otherwise pppd will exit. If this signal is
1922 received during the holdoff period, it causes pppd to end the
1923 holdoff period immediately. If a connector or disconnector
1924 process is running, pppd will send the same signal to its
1925 process group.
1926 SIGUSR1
1928 This signal toggles the state of the debug option.
1929 SIGUSR2
1931 This signal causes pppd to renegotiate compression. This can be
1932 useful to re-enable compression after it has been disabled as a
1933 result of a fatal decompression error. (Fatal decompression er‐
1934 rors generally indicate a bug in one or other implementation.)
1935
1938 Paul Mackerras (paulus@samba.org), based on earlier work by Drew
1939 Perkins, Brad Clements, Karl Fox, Greg Christy, and Brad Parker.
1940
1943 Pppd is copyrighted and made available under conditions which provide
1944 that it may be copied and used in source or binary forms provided that
1945 the conditions listed below are met. Portions of pppd are covered by
1946 the following copyright notices:
1947 Copyright (c) 1984-2000 Carnegie Mellon University. All rights re‐
1949 served.
1950 Copyright (c) 1993-2004 Paul Mackerras. All rights reserved.
1951 Copyright (c) 1995 Pedro Roque Marques. All rights reserved.
1952 Copyright (c) 1995 Eric Rosenquist. All rights reserved.
1953 Copyright (c) 1999 Tommi Komulainen. All rights reserved.
1954 Copyright (C) Andrew Tridgell 1999
1955 Copyright (c) 2000 by Sun Microsystems, Inc. All rights reserved.
1956 Copyright (c) 2001 by Sun Microsystems, Inc. All rights reserved.
1957 Copyright (c) 2002 Google, Inc. All rights reserved.
1958 The copyright notices contain the following statements.
1960 Redistribution and use in source and binary forms, with or without mod‐
1962 ification, are permitted provided that the following conditions are
1963 met:
1964 1. Redistributions of source code must retain the above copyright
1966 notice, this list of conditions and the following disclaimer.
1967 2. Redistributions in binary form must reproduce the above copyright
1969 notice, this list of conditions and the following disclaimer in
1970 the documentation and/or other materials provided with the
1971 distribution.
1972 3. The name "Carnegie Mellon University" must not be used to
1974 endorse or promote products derived from this software without
1975 prior written permission. For permission or any legal
1976 details, please contact
1977 Office of Technology Transfer
1978 Carnegie Mellon University
1979 5000 Forbes Avenue
1980 Pittsburgh, PA 15213-3890
1981 (412) 268-4387, fax: (412) 268-7395
1982 tech-transfer@andrew.cmu.edu
1983 3b. The name(s) of the authors of this software must not be used to
1985 endorse or promote products derived from this software without
1986 prior written permission.
1987 4. Redistributions of any form whatsoever must retain the following
1989 acknowledgements:
1990 "This product includes software developed by Computing Services
1991 at Carnegie Mellon University (http://www.cmu.edu/computing/)."
1992 "This product includes software developed by Paul Mackerras
1993 <paulus@samba.org>".
1994 "This product includes software developed by Pedro Roque Marques
1995 <pedro_m@yahoo.com>".
1996 "This product includes software developed by Tommi Komulainen
1997 <Tommi.Komulainen@iki.fi>".
1998 CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
2000 SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FIT‐
2001 NESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE FOR ANY
2002 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
2003 RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
2004 CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
2005 CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
2006 THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
2008 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
2009 FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDI‐
2010 RECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
2011 LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLI‐
2012 GENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH
2013 THE USE OR PERFORMANCE OF THIS SOFTWARE.
2014 PPPD(8)