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
19 besides 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 4.4BSD and Net‐
34 BSD, any speed can be specified. Other systems (e.g. Linux,
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
43 encoded 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
101 default value of -1, the route is only added if there is no
102 default route at all.
103 defaultroute6
105 Add a default IPv6 route to the system routing tables, using the
106 peer as the gateway, when IPv6CP negotiation is successfully
107 completed. This entry is removed when the PPP connection is
108 broken. This option is privileged if the nodefaultroute6 option
109 has been specified.
110 disconnect script
112 Execute the command specified by script, by passing it to a
113 shell, after pppd has terminated the link. This command could,
114 for example, issue commands to the modem to cause it to hang up
115 if hardware modem control signals were not available. The dis‐
116 connect script is not run if the modem has already hung up. A
117 value for this option from a privileged source cannot be over‐
118 ridden by a non-privileged user.
119 escape xx,yy,...
121 Specifies that certain characters should be escaped on transmis‐
122 sion (regardless of whether the peer requests them to be escaped
123 with its async control character map). The characters to be
124 escaped are specified as a list of hex numbers separated by com‐
125 mas. Note that almost any character can be specified for the
126 escape option, unlike the asyncmap option which only allows con‐
127 trol characters to be specified. The characters which may not
128 be escaped are those with hex values 0x20 - 0x3f or 0x5e.
129 file name
131 Read options from file name (the format is described below).
132 The file must be readable by the user who has invoked pppd.
133 init script
135 Execute the command specified by script, by passing it to a
136 shell, to initialize the serial line. This script would typi‐
137 cally use the chat(8) program to configure the modem to enable
138 auto answer. A value for this option from a privileged source
139 cannot be overridden by a non-privileged user.
140 lock Specifies that pppd should create a UUCP-style lock file for the
142 serial device to ensure exclusive access to the device. By
143 default, pppd will not create a lock file.
144 mru n Set the MRU [Maximum Receive Unit] value to n. Pppd will ask the
146 peer to send packets of no more than n bytes. The value of n
147 must be between 128 and 16384; the default is 1500. A value of
148 296 works well on very slow links (40 bytes for TCP/IP header +
149 256 bytes of data). Note that for the IPv6 protocol, the MRU
150 must be at least 1280.
151 mtu n Set the MTU [Maximum Transmit Unit] value to n. Unless the peer
153 requests a smaller value via MRU negotiation, pppd will request
154 that the kernel networking code send data packets of no more
155 than n bytes through the PPP network interface. Note that for
156 the IPv6 protocol, the MTU must be at least 1280.
157 passive
159 Enables the "passive" option in the LCP. With this option, pppd
160 will attempt to initiate a connection; if no reply is received
161 from the peer, pppd will then just wait passively for a valid
162 LCP packet from the peer, instead of exiting, as it would with‐
163 out this option.
164
166 <local_IP_address>:<remote_IP_address>
167 Set the local and/or remote interface IP addresses. Either one
168 may be omitted. The IP addresses can be specified with a host
169 name or in decimal dot notation (e.g. 150.234.56.78). The
170 default local address is the (first) IP address of the system
171 (unless the noipdefault option is given). The remote address
172 will be obtained from the peer if not specified in any option.
173 Thus, in simple cases, this option is not required. If a local
174 and/or remote IP address is specified with this option, pppd
175 will not accept a different value from the peer in the IPCP
176 negotiation, unless the ipcp-accept-local and/or
177 ipcp-accept-remote options are given, respectively.
178 +ipv6 Enable the IPv6CP and IPv6 protocols.
180 ipv6 <local_interface_identifier>,<remote_interface_identifier>
182 Set the local and/or remote 64-bit interface identifier. Either
183 one may be omitted. The identifier must be specified in standard
184 ASCII notation of IPv6 addresses (e.g. ::dead:beef). If the
185 ipv6cp-use-ipaddr option is given, the local identifier is the
186 local IPv4 address (see above). On systems which supports a
187 unique persistent id, such as EUI-48 derived from the Ethernet
188 MAC address, ipv6cp-use-persistent option can be used to replace
189 the ipv6 <local>,<remote> option. Otherwise the identifier is
190 randomized.
191 active-filter filter-expression
193 Specifies a packet filter to be applied to data packets to
194 determine which packets are to be regarded as link activity, and
195 therefore reset the idle timer, or cause the link to be brought
196 up in demand-dialling mode. This option is useful in conjunc‐
197 tion with the idle option if there are packets being sent or
198 received regularly over the link (for example, routing informa‐
199 tion packets) which would otherwise prevent the link from ever
200 appearing to be idle. The filter-expression syntax is as
201 described for tcpdump(1), except that qualifiers which are inap‐
202 propriate for a PPP link, such as ether and arp, are not permit‐
203 ted. Generally the filter expression should be enclosed in sin‐
204 gle-quotes to prevent whitespace in the expression from being
205 interpreted by the shell. This option is currently only avail‐
206 able under Linux, and requires that the kernel was configured to
207 include PPP filtering support (CONFIG_PPP_FILTER). Note that it
208 is possible to apply different constraints to incoming and out‐
209 going packets using the inbound and outbound qualifiers.
210 allow-ip address(es)
212 Allow peers to use the given IP address or subnet without
213 authenticating themselves. The parameter is parsed as for each
214 element of the list of allowed IP addresses in the secrets files
215 (see the AUTHENTICATION section below).
216 allow-number number
218 Allow peers to connect from the given telephone number. A
219 trailing `*' character will match all numbers beginning with the
220 leading part.
221 bsdcomp nr,nt
223 Request that the peer compress packets that it sends, using the
224 BSD-Compress scheme, with a maximum code size of nr bits, and
225 agree to compress packets sent to the peer with a maximum code
226 size of nt bits. If nt is not specified, it defaults to the
227 value given for nr. Values in the range 9 to 15 may be used for
228 nr and nt; larger values give better compression but consume
229 more kernel memory for compression dictionaries. Alternatively,
230 a value of 0 for nr or nt disables compression in the corre‐
231 sponding direction. Use nobsdcomp or bsdcomp 0 to disable BSD-
232 Compress compression entirely.
233 ca ca-file
235 (EAP-TLS) Use the file ca-file as the X.509 Certificate Author‐
236 ity (CA) file (in PEM format), needed for setting up an EAP-TLS
237 connection. This option is used on the client-side in conjunc‐
238 tion with the cert and key options.
239 cdtrcts
241 Use a non-standard hardware flow control (i.e. DTR/CTS) to con‐
242 trol the flow of data on the serial port. If neither the
243 crtscts, the nocrtscts, the cdtrcts nor the nocdtrcts option is
244 given, the hardware flow control setting for the serial port is
245 left unchanged. Some serial ports (such as Macintosh serial
246 ports) lack a true RTS output. Such serial ports use this mode
247 to implement true bi-directional flow control. The sacrifice is
248 that this flow control mode does not permit using DTR as a modem
249 control line.
250 cert certfile
252 (EAP-TLS) Use the file certfile as the X.509 certificate (in PEM
253 format), needed for setting up an EAP-TLS connection. This
254 option is used on the client-side in conjunction with the ca and
255 key options.
256 chap-interval n
258 If this option is given, pppd will rechallenge the peer every n
259 seconds.
260 chap-max-challenge n
262 Set the maximum number of CHAP challenge transmissions to n
263 (default 10).
264 chap-restart n
266 Set the CHAP restart interval (retransmission timeout for chal‐
267 lenges) to n seconds (default 3).
268 child-timeout n
270 When exiting, wait for up to n seconds for any child processes
271 (such as the command specified with the pty command) to exit
272 before exiting. At the end of the timeout, pppd will send a
273 SIGTERM signal to any remaining child processes and exit. A
274 value of 0 means no timeout, that is, pppd will wait until all
275 child processes have exited.
276 connect-delay n
278 Wait for up to n milliseconds after the connect script finishes
279 for a valid PPP packet from the peer. At the end of this time,
280 or when a valid PPP packet is received from the peer, pppd will
281 commence negotiation by sending its first LCP packet. The
282 default value is 1000 (1 second). This wait period only applies
283 if the connect or pty option is used.
284 crl filename
286 (EAP-TLS) Use the file filename as the Certificate Revocation
287 List to check for the validity of the peer's certificate. This
288 option is not mandatory for setting up an EAP-TLS connection.
289 Also see the crl-dir option.
290 crl-dir directory
292 (EAP-TLS) Use the directory directory to scan for CRL files in
293 has format ($hash.r0) to check for the validity of the peer's
294 certificate. This option is not mandatory for setting up an
295 EAP-TLS connection. Also see the crl option.
296 debug Enables connection debugging facilities. If this option is
298 given, pppd will log the contents of all control packets sent or
299 received in a readable form. The packets are logged through
300 syslog with facility daemon and level debug. This information
301 can be directed to a file by setting up /etc/syslog.conf appro‐
302 priately (see syslog.conf(5)).
303 default-asyncmap
305 Disable asyncmap negotiation, forcing all control characters to
306 be escaped for both the transmit and the receive direction.
307 default-mru
309 Disable MRU [Maximum Receive Unit] negotiation. With this
310 option, pppd will use the default MRU value of 1500 bytes for
311 both the transmit and receive direction.
312 deflate nr,nt
314 Request that the peer compress packets that it sends, using the
315 Deflate scheme, with a maximum window size of 2**nr bytes, and
316 agree to compress packets sent to the peer with a maximum window
317 size of 2**nt bytes. If nt is not specified, it defaults to the
318 value given for nr. Values in the range 9 to 15 may be used for
319 nr and nt; larger values give better compression but consume
320 more kernel memory for compression dictionaries. Alternatively,
321 a value of 0 for nr or nt disables compression in the corre‐
322 sponding direction. Use nodeflate or deflate 0 to disable
323 Deflate compression entirely. (Note: pppd requests Deflate com‐
324 pression in preference to BSD-Compress if the peer can do
325 either.)
326 demand Initiate the link only on demand, i.e. when data traffic is
328 present. With this option, the remote IP address may be speci‐
329 fied by the user on the command line or in an options file, or
330 if not, pppd will use an arbitrary address in the 10.x.x.x
331 range. Pppd will initially configure the interface and enable
332 it for IP traffic without connecting to the peer. When traffic
333 is available, pppd will connect to the peer and perform negotia‐
334 tion, authentication, etc. When this is completed, pppd will
335 commence passing data packets (i.e., IP packets) across the
336 link.
337 The demand option implies the persist option. If this behaviour
339 is not desired, use the nopersist option after the demand
340 option. The idle and holdoff options are also useful in con‐
341 junction with the demand option.
342 domain d
344 Append the domain name d to the local host name for authentica‐
345 tion purposes. For example, if gethostname() returns the name
346 porsche, but the fully qualified domain name is
347 porsche.Quotron.COM, you could specify domain Quotron.COM. Pppd
348 would then use the name porsche.Quotron.COM for looking up
349 secrets in the secrets file, and as the default name to send to
350 the peer when authenticating itself to the peer. This option is
351 privileged.
352 dryrun With the dryrun option, pppd will print out all the option val‐
354 ues which have been set and then exit, after parsing the command
355 line and options files and checking the option values, but
356 before initiating the link. The option values are logged at
357 level info, and also printed to standard output unless the
358 device on standard output is the device that pppd would be using
359 to communicate with the peer.
360 dump With the dump option, pppd will print out all the option values
362 which have been set. This option is like the dryrun option
363 except that pppd proceeds as normal rather than exiting.
364 enable-session
366 Enables session accounting via PAM or wtwp/wtmpx, as appropri‐
367 ate. When PAM is enabled, the PAM "account" and "session" mod‐
368 ule stacks determine behavior, and are enabled for all PPP
369 authentication protocols. When PAM is disabled, wtmp/wtmpx
370 entries are recorded regardless of whether the peer name identi‐
371 fies a valid user on the local system, making peers visible in
372 the last(1) log. This feature is automatically enabled when the
373 pppd login option is used. Session accounting is disabled by
374 default.
375 endpoint <epdisc>
377 Sets the endpoint discriminator sent by the local machine to the
378 peer during multilink negotiation to <epdisc>. The default is
379 to use the MAC address of the first ethernet interface on the
380 system, if any, otherwise the IPv4 address corresponding to the
381 hostname, if any, provided it is not in the multicast or
382 locally-assigned IP address ranges, or the localhost address.
383 The endpoint discriminator can be the string null or of the form
384 type:value, where type is a decimal number or one of the strings
385 local, IP, MAC, magic, or phone. The value is an IP address in
386 dotted-decimal notation for the IP type, or a string of bytes in
387 hexadecimal, separated by periods or colons for the other types.
388 For the MAC type, the value may also be the name of an ethernet
389 or similar network interface. This option is currently only
390 available under Linux.
391 eap-interval n
393 If this option is given and pppd authenticates the peer with EAP
394 (i.e., is the server), pppd will restart EAP authentication
395 every n seconds. For EAP SRP-SHA1, see also the srp-interval
396 option, which enables lightweight rechallenge.
397 eap-max-rreq n
399 Set the maximum number of EAP Requests to which pppd will
400 respond (as a client) without hearing EAP Success or Failure.
401 (Default is 20.)
402 eap-max-sreq n
404 Set the maximum number of EAP Requests that pppd will issue (as
405 a server) while attempting authentication. (Default is 10.)
406 eap-restart n
408 Set the retransmit timeout for EAP Requests when acting as a
409 server (authenticator). (Default is 3 seconds.)
410 eap-timeout n
412 Set the maximum time to wait for the peer to send an EAP Request
413 when acting as a client (authenticatee). (Default is 20 sec‐
414 onds.)
415 hide-password
417 When logging the contents of PAP packets, this option causes
418 pppd to exclude the password string from the log. This is the
419 default.
420 holdoff n
422 Specifies how many seconds to wait before re-initiating the link
423 after it terminates. This option only has any effect if the
424 persist or demand option is used. The holdoff period is not
425 applied if the link was terminated because it was idle.
426 idle n Specifies that pppd should disconnect if the link is idle for n
428 seconds. The link is idle when no data packets (i.e. IP pack‐
429 ets) are being sent or received. Note: it is not advisable to
430 use this option with the persist option without the demand
431 option. If the active-filter option is given, data packets
432 which are rejected by the specified activity filter also count
433 as the link being idle.
434 ipcp-accept-local
436 With this option, pppd will accept the peer's idea of our local
437 IP address, even if the local IP address was specified in an
438 option.
439 ipcp-accept-remote
441 With this option, pppd will accept the peer's idea of its
442 (remote) IP address, even if the remote IP address was specified
443 in an option.
444 ipcp-max-configure n
446 Set the maximum number of IPCP configure-request transmissions
447 to n (default 10).
448 ipcp-max-failure n
450 Set the maximum number of IPCP configure-NAKs returned before
451 starting to send configure-Rejects instead to n (default 10).
452 ipcp-max-terminate n
454 Set the maximum number of IPCP terminate-request transmissions
455 to n (default 3).
456 ipcp-restart n
458 Set the IPCP restart interval (retransmission timeout) to n sec‐
459 onds (default 3).
460 ipparam string
462 Provides an extra parameter to the ip-up, ip-pre-up and ip-down
463 scripts. If this option is given, the string supplied is given
464 as the 6th parameter to those scripts.
465 ipv6cp-accept-local
467 With this option, pppd will accept the peer's idea of our local
468 IPv6 interface identifier, even if the local IPv6 interface
469 identifier was specified in an option.
470 ipv6cp-max-configure n
472 Set the maximum number of IPv6CP configure-request transmissions
473 to n (default 10).
474 ipv6cp-max-failure n
476 Set the maximum number of IPv6CP configure-NAKs returned before
477 starting to send configure-Rejects instead to n (default 10).
478 ipv6cp-max-terminate n
480 Set the maximum number of IPv6CP terminate-request transmissions
481 to n (default 3).
482 ipv6cp-restart n
484 Set the IPv6CP restart interval (retransmission timeout) to n
485 seconds (default 3).
486 ipx Enable the IPXCP and IPX protocols. This option is presently
488 only supported under Linux, and only if your kernel has been
489 configured to include IPX support.
490 ipx-network n
492 Set the IPX network number in the IPXCP configure request frame
493 to n, a hexadecimal number (without a leading 0x). There is no
494 valid default. If this option is not specified, the network
495 number is obtained from the peer. If the peer does not have the
496 network number, the IPX protocol will not be started.
497 ipx-node n:m
499 Set the IPX node numbers. The two node numbers are separated
500 from each other with a colon character. The first number n is
501 the local node number. The second number m is the peer's node
502 number. Each node number is a hexadecimal number, at most 10
503 digits long. The node numbers on the ipx-network must be unique.
504 There is no valid default. If this option is not specified then
505 the node numbers are obtained from the peer.
506 ipx-router-name <string>
508 Set the name of the router. This is a string and is sent to the
509 peer as information data.
510 ipx-routing n
512 Set the routing protocol to be received by this option. More
513 than one instance of ipx-routing may be specified. The 'none'
514 option (0) may be specified as the only instance of ipx-routing.
515 The values may be 0 for NONE, 2 for RIP/SAP, and 4 for NLSP.
516 ipxcp-accept-local
518 Accept the peer's NAK for the node number specified in the
519 ipx-node option. If a node number was specified, and non-zero,
520 the default is to insist that the value be used. If you include
521 this option then you will permit the peer to override the entry
522 of the node number.
523 ipxcp-accept-network
525 Accept the peer's NAK for the network number specified in the
526 ipx-network option. If a network number was specified, and non-
527 zero, the default is to insist that the value be used. If you
528 include this option then you will permit the peer to override
529 the entry of the node number.
530 ipxcp-accept-remote
532 Use the peer's network number specified in the configure request
533 frame. If a node number was specified for the peer and this
534 option was not specified, the peer will be forced to use the
535 value which you have specified.
536 ipxcp-max-configure n
538 Set the maximum number of IPXCP configure request frames which
539 the system will send to n. The default is 10.
540 ipxcp-max-failure n
542 Set the maximum number of IPXCP NAK frames which the local sys‐
543 tem will send before it rejects the options. The default value
544 is 3.
545 ipxcp-max-terminate n
547 Set the maximum number of IPXCP terminate request frames before
548 the local system considers that the peer is not listening to
549 them. The default value is 3.
550 kdebug n
552 Enable debugging code in the kernel-level PPP driver. The argu‐
553 ment values depend on the specific kernel driver, but in general
554 a value of 1 will enable general kernel debug messages. (Note
555 that these messages are usually only useful for debugging the
556 kernel driver itself.) For the Linux 2.2.x kernel driver, the
557 value is a sum of bits: 1 to enable general debug messages, 2 to
558 request that the contents of received packets be printed, and 4
559 to request that the contents of transmitted packets be printed.
560 On most systems, messages printed by the kernel are logged by
561 syslog(1) to a file as directed in the /etc/syslog.conf configu‐
562 ration file.
563 key keyfile
565 (EAP-TLS) Use the file keyfile as the private key file (in PEM
566 format), needed for setting up an EAP-TLS connection. This
567 option is used on the client-side in conjunction with the ca and
568 cert options.
569 ktune Enables pppd to alter kernel settings as appropriate. Under
571 Linux, pppd will enable IP forwarding (i.e. set
572 /proc/sys/net/ipv4/ip_forward to 1) if the proxyarp option is
573 used, and will enable the dynamic IP address option (i.e. set
574 /proc/sys/net/ipv4/ip_dynaddr to 1) in demand mode if the local
575 address changes.
576 lcp-echo-failure n
578 If this option is given, pppd will presume the peer to be dead
579 if n LCP echo-requests are sent without receiving a valid LCP
580 echo-reply. If this happens, pppd will terminate the connec‐
581 tion. Use of this option requires a non-zero value for the
582 lcp-echo-interval parameter. This option can be used to enable
583 pppd to terminate after the physical connection has been broken
584 (e.g., the modem has hung up) in situations where no hardware
585 modem control lines are available.
586 lcp-echo-interval n
588 If this option is given, pppd will send an LCP echo-request
589 frame to the peer every n seconds. Normally the peer should
590 respond to the echo-request by sending an echo-reply. This
591 option can be used with the lcp-echo-failure option to detect
592 that the peer is no longer connected.
593 lcp-max-configure n
595 Set the maximum number of LCP configure-request transmissions to
596 n (default 10).
597 lcp-max-failure n
599 Set the maximum number of LCP configure-NAKs returned before
600 starting to send configure-Rejects instead to n (default 10).
601 lcp-max-terminate n
603 Set the maximum number of LCP terminate-request transmissions to
604 n (default 3).
605 lcp-restart n
607 Set the LCP restart interval (retransmission timeout) to n sec‐
608 onds (default 3).
609 linkname name
611 Sets the logical name of the link to name. Pppd will create a
612 file named ppp-name.pid in /var/run (or /etc/ppp on some sys‐
613 tems) containing its process ID. This can be useful in deter‐
614 mining which instance of pppd is responsible for the link to a
615 given peer system. This is a privileged option.
616 local Don't use the modem control lines. With this option, pppd will
618 ignore the state of the CD (Carrier Detect) signal from the
619 modem and will not change the state of the DTR (Data Terminal
620 Ready) signal. This is the opposite of the modem option.
621 logfd n
623 Send log messages to file descriptor n. Pppd will send log mes‐
624 sages to at most one file or file descriptor (as well as sending
625 the log messages to syslog), so this option and the logfile
626 option are mutually exclusive. The default is for pppd to send
627 log messages to stdout (file descriptor 1), unless the serial
628 port is already open on stdout.
629 logfile filename
631 Append log messages to the file filename (as well as sending the
632 log messages to syslog). The file is opened with the privileges
633 of the user who invoked pppd, in append mode.
634 login Use the system password database for authenticating the peer
636 using PAP, and record the user in the system wtmp file. Note
637 that the peer must have an entry in the /etc/ppp/pap-secrets
638 file as well as the system password database to be allowed
639 access. See also the enable-session option.
640 master_detach
642 If multilink is enabled and this pppd process is the multilink
643 bundle master, and the link controlled by this pppd process ter‐
644 minates, this pppd process continues to run in order to maintain
645 the bundle. If the master_detach option has been given, pppd
646 will detach from its controlling terminal in this situation,
647 even if the nodetach option has been given.
648 maxconnect n
650 Terminate the connection when it has been available for network
651 traffic for n seconds (i.e. n seconds after the first network
652 control protocol comes up).
653 maxfail n
655 Terminate after n consecutive failed connection attempts. A
656 value of 0 means no limit. The default value is 10.
657 modem Use the modem control lines. This option is the default. With
659 this option, pppd will wait for the CD (Carrier Detect) signal
660 from the modem to be asserted when opening the serial device
661 (unless a connect script is specified), and it will drop the DTR
662 (Data Terminal Ready) signal briefly when the connection is ter‐
663 minated and before executing the connect script. On Ultrix,
664 this option implies hardware flow control, as for the crtscts
665 option. This is the opposite of the local option.
666 mp Enables the use of PPP multilink; this is an alias for the `mul‐
668 tilink' option. This option is currently only available under
669 Linux.
670 mppe-stateful
672 Allow MPPE to use stateful mode. Stateless mode is still
673 attempted first. The default is to disallow stateful mode.
674 mpshortseq
676 Enables the use of short (12-bit) sequence numbers in multilink
677 headers, as opposed to 24-bit sequence numbers. This option is
678 only available under Linux, and only has any effect if multilink
679 is enabled (see the multilink option).
680 mrru n Sets the Maximum Reconstructed Receive Unit to n. The MRRU is
682 the maximum size for a received packet on a multilink bundle,
683 and is analogous to the MRU for the individual links. This
684 option is currently only available under Linux, and only has any
685 effect if multilink is enabled (see the multilink option).
686 ms-dns <addr>
688 If pppd is acting as a server for Microsoft Windows clients,
689 this option allows pppd to supply one or two DNS (Domain Name
690 Server) addresses to the clients. The first instance of this
691 option specifies the primary DNS address; the second instance
692 (if given) specifies the secondary DNS address. (This option
693 was present in some older versions of pppd under the name
694 dns-addr.)
695 ms-wins <addr>
697 If pppd is acting as a server for Microsoft Windows or "Samba"
698 clients, this option allows pppd to supply one or two WINS (Win‐
699 dows Internet Name Services) server addresses to the clients.
700 The first instance of this option specifies the primary WINS
701 address; the second instance (if given) specifies the secondary
702 WINS address.
703 multilink
705 Enables the use of the PPP multilink protocol. If the peer also
706 supports multilink, then this link can become part of a bundle
707 between the local system and the peer. If there is an existing
708 bundle to the peer, pppd will join this link to that bundle,
709 otherwise pppd will create a new bundle. See the MULTILINK sec‐
710 tion below. This option is currently only available under
711 Linux.
712 name name
714 Set the name of the local system for authentication purposes to
715 name. This is a privileged option. With this option, pppd will
716 use lines in the secrets files which have name as the second
717 field when looking for a secret to use in authenticating the
718 peer. In addition, unless overridden with the user option, name
719 will be used as the name to send to the peer when authenticating
720 the local system to the peer. (Note that pppd does not append
721 the domain name to name.)
722 noaccomp
724 Disable Address/Control compression in both directions (send and
725 receive).
726 need-peer-eap
728 (EAP-TLS) Require the peer to verify our authentication creden‐
729 tials.
730 noauth Do not require the peer to authenticate itself. This option is
732 privileged.
733 nobsdcomp
735 Disables BSD-Compress compression; pppd will not request or
736 agree to compress packets using the BSD-Compress scheme.
737 noccp Disable CCP (Compression Control Protocol) negotiation. This
739 option should only be required if the peer is buggy and gets
740 confused by requests from pppd for CCP negotiation.
741 nocrtscts
743 Disable hardware flow control (i.e. RTS/CTS) on the serial port.
744 If neither the crtscts nor the nocrtscts nor the cdtrcts nor the
745 nocdtrcts option is given, the hardware flow control setting for
746 the serial port is left unchanged.
747 nocdtrcts
749 This option is a synonym for nocrtscts. Either of these options
750 will disable both forms of hardware flow control.
751 nodefaultroute
753 Disable the defaultroute option. The system administrator who
754 wishes to prevent users from creating default routes with pppd
755 can do so by placing this option in the /etc/ppp/options file.
756 nodefaultroute6
758 Disable the defaultroute6 option. The system administrator who
759 wishes to prevent users from adding a default route with pppd
760 can do so by placing this option in the /etc/ppp/options file.
761 nodeflate
763 Disables Deflate compression; pppd will not request or agree to
764 compress packets using the Deflate scheme.
765 nodetach
767 Don't detach from the controlling terminal. Without this
768 option, if a serial device other than the terminal on the stan‐
769 dard input is specified, pppd will fork to become a background
770 process.
771 noendpoint
773 Disables pppd from sending an endpoint discriminator to the peer
774 or accepting one from the peer (see the MULTILINK section
775 below). This option should only be required if the peer is
776 buggy.
777 noip Disable IPCP negotiation and IP communication. This option
779 should only be required if the peer is buggy and gets confused
780 by requests from pppd for IPCP negotiation.
781 noipv6 Disable IPv6CP negotiation and IPv6 communication. This option
783 should only be required if the peer is buggy and gets confused
784 by requests from pppd for IPv6CP negotiation.
785 noipdefault
787 Disables the default behaviour when no local IP address is spec‐
788 ified, which is to determine (if possible) the local IP address
789 from the hostname. With this option, the peer will have to sup‐
790 ply the local IP address during IPCP negotiation (unless it
791 specified explicitly on the command line or in an options file).
792 noipx Disable the IPXCP and IPX protocols. This option should only be
794 required if the peer is buggy and gets confused by requests from
795 pppd for IPXCP negotiation.
796 noktune
798 Opposite of the ktune option; disables pppd from changing system
799 settings.
800 nolock Opposite of the lock option; specifies that pppd should not cre‐
802 ate a UUCP-style lock file for the serial device. This option
803 is privileged.
804 nolog Do not send log messages to a file or file descriptor. This
806 option cancels the logfd and logfile options.
807 nomagic
809 Disable magic number negotiation. With this option, pppd cannot
810 detect a looped-back line. This option should only be needed if
811 the peer is buggy.
812 nomp Disables the use of PPP multilink. This option is currently
814 only available under Linux.
815 nomppe Disables MPPE (Microsoft Point to Point Encryption). This is
817 the default.
818 nomppe-40
820 Disable 40-bit encryption with MPPE.
821 nomppe-128
823 Disable 128-bit encryption with MPPE.
824 nomppe-stateful
826 Disable MPPE stateful mode. This is the default.
827 nompshortseq
829 Disables the use of short (12-bit) sequence numbers in the PPP
830 multilink protocol, forcing the use of 24-bit sequence numbers.
831 This option is currently only available under Linux, and only
832 has any effect if multilink is enabled.
833 nomultilink
835 Disables the use of PPP multilink. This option is currently
836 only available under Linux.
837 nopcomp
839 Disable protocol field compression negotiation in both the
840 receive and the transmit direction.
841 nopersist
843 Exit once a connection has been made and terminated. This is
844 the default unless the persist or demand option has been speci‐
845 fied.
846 nopredictor1
848 Do not accept or agree to Predictor-1 compression.
849 noproxyarp
851 Disable the proxyarp option. The system administrator who
852 wishes to prevent users from creating proxy ARP entries with
853 pppd can do so by placing this option in the /etc/ppp/options
854 file.
855 noremoteip
857 Allow pppd to operate without having an IP address for the peer.
858 This option is only available under Linux. Normally, pppd will
859 request the peer's IP address, and if the peer does not supply
860 it, pppd will use an arbitrary address in the 10.x.x.x subnet.
861 With this option, if the peer does not supply its IP address,
862 pppd will not ask the peer for it, and will not set the destina‐
863 tion address of the ppp interface. In this situation, the ppp
864 interface can be used for routing by creating device routes, but
865 the peer itself cannot be addressed directly for IP traffic.
866 notty Normally, pppd requires a terminal device. With this option,
868 pppd will allocate itself a pseudo-tty master/slave pair and use
869 the slave as its terminal device. Pppd will create a child
870 process to act as a `character shunt' to transfer characters
871 between the pseudo-tty master and its standard input and output.
872 Thus pppd will transmit characters on its standard output and
873 receive characters on its standard input even if they are not
874 terminal devices. This option increases the latency and CPU
875 overhead of transferring data over the ppp interface as all of
876 the characters sent and received must flow through the character
877 shunt process. An explicit device name may not be given if this
878 option is used.
879 novj Disable Van Jacobson style TCP/IP header compression in both the
881 transmit and the receive direction.
882 novjccomp
884 Disable the connection-ID compression option in Van Jacobson
885 style TCP/IP header compression. With this option, pppd will
886 not omit the connection-ID byte from Van Jacobson compressed
887 TCP/IP headers, nor ask the peer to do so.
888 papcrypt
890 Indicates that all secrets in the /etc/ppp/pap-secrets file
891 which are used for checking the identity of the peer are
892 encrypted, and thus pppd should not accept a password which,
893 before encryption, is identical to the secret from the
894 /etc/ppp/pap-secrets file.
895 pap-max-authreq n
897 Set the maximum number of PAP authenticate-request transmissions
898 to n (default 10).
899 pap-restart n
901 Set the PAP restart interval (retransmission timeout) to n sec‐
902 onds (default 3).
903 pap-timeout n
905 Set the maximum time that pppd will wait for the peer to authen‐
906 ticate itself with PAP to n seconds (0 means no limit).
907 pass-filter filter-expression
909 Specifies a packet filter to applied to data packets being sent
910 or received to determine which packets should be allowed to
911 pass. Packets which are rejected by the filter are silently
912 discarded. This option can be used to prevent specific network
913 daemons (such as routed) using up link bandwidth, or to provide
914 a very basic firewall capability. The filter-expression syntax
915 is as described for tcpdump(1), except that qualifiers which are
916 inappropriate for a PPP link, such as ether and arp, are not
917 permitted. Generally the filter expression should be enclosed
918 in single-quotes to prevent whitespace in the expression from
919 being interpreted by the shell. Note that it is possible to
920 apply different constraints to incoming and outgoing packets
921 using the inbound and outbound qualifiers. This option is cur‐
922 rently only available under Linux, and requires that the kernel
923 was configured to include PPP filtering support (CONFIG_PPP_FIL‐
924 TER).
925 password password-string
927 Specifies the password to use for authenticating to the peer.
928 Use of this option is discouraged, as the password is likely to
929 be visible to other users on the system (for example, by using
930 ps(1)).
931 persist
933 Do not exit after a connection is terminated; instead try to
934 reopen the connection. The maxfail option still has an effect on
935 persistent connections.
936 plugin filename
938 Load the shared library object file filename as a plugin. This
939 is a privileged option. If filename does not contain a slash
940 (/), pppd will look in the /usr/lib/pppd/version directory for
941 the plugin, where version is the version number of pppd (for
942 example, 2.4.2).
943 predictor1
945 Request that the peer compress frames that it sends using Pre‐
946 dictor-1 compression, and agree to compress transmitted frames
947 with Predictor-1 if requested. This option has no effect unless
948 the kernel driver supports Predictor-1 compression.
949 privgroup group-name
951 Allows members of group group-name to use privileged options.
952 This is a privileged option. Use of this option requires care
953 as there is no guarantee that members of group-name cannot use
954 pppd to become root themselves. Consider it equivalent to
955 putting the members of group-name in the kmem or disk group.
956 proxyarp
958 Add an entry to this system's ARP [Address Resolution Protocol]
959 table with the IP address of the peer and the Ethernet address
960 of this system. This will have the effect of making the peer
961 appear to other systems to be on the local ethernet.
962 pty script
964 Specifies that the command script is to be used to communicate
965 rather than a specific terminal device. Pppd will allocate
966 itself a pseudo-tty master/slave pair and use the slave as its
967 terminal device. The script will be run in a child process with
968 the pseudo-tty master as its standard input and output. An
969 explicit device name may not be given if this option is used.
970 (Note: if the record option is used in conjunction with the pty
971 option, the child process will have pipes on its standard input
972 and output.)
973 receive-all
975 With this option, pppd will accept all control characters from
976 the peer, including those marked in the receive asyncmap. With‐
977 out this option, pppd will discard those characters as specified
978 in RFC1662. This option should only be needed if the peer is
979 buggy.
980 record filename
982 Specifies that pppd should record all characters sent and
983 received to a file named filename. This file is opened in
984 append mode, using the user's user-ID and permissions. This
985 option is implemented using a pseudo-tty and a process to trans‐
986 fer characters between the pseudo-tty and the real serial
987 device, so it will increase the latency and CPU overhead of
988 transferring data over the ppp interface. The characters are
989 stored in a tagged format with timestamps, which can be dis‐
990 played in readable form using the pppdump(8) program.
991 remotename name
993 Set the assumed name of the remote system for authentication
994 purposes to name.
995 remotenumber number
997 Set the assumed telephone number of the remote system for
998 authentication purposes to number.
999 refuse-chap
1001 With this option, pppd will not agree to authenticate itself to
1002 the peer using CHAP.
1003 refuse-mschap
1005 With this option, pppd will not agree to authenticate itself to
1006 the peer using MS-CHAP.
1007 refuse-mschap-v2
1009 With this option, pppd will not agree to authenticate itself to
1010 the peer using MS-CHAPv2.
1011 refuse-eap
1013 With this option, pppd will not agree to authenticate itself to
1014 the peer using EAP.
1015 refuse-pap
1017 With this option, pppd will not agree to authenticate itself to
1018 the peer using PAP.
1019 require-chap
1021 Require the peer to authenticate itself using CHAP [Challenge
1022 Handshake Authentication Protocol] authentication.
1023 require-mppe
1025 Require the use of MPPE (Microsoft Point to Point Encryption).
1026 This option disables all other compression types. This option
1027 enables both 40-bit and 128-bit encryption. In order for MPPE
1028 to successfully come up, you must have authenticated with either
1029 MS-CHAP or MS-CHAPv2. This option is presently only supported
1030 under Linux, and only if your kernel has been configured to
1031 include MPPE support.
1032 require-mppe-40
1034 Require the use of MPPE, with 40-bit encryption.
1035 require-mppe-128
1037 Require the use of MPPE, with 128-bit encryption.
1038 require-mschap
1040 Require the peer to authenticate itself using MS-CHAP [Microsoft
1041 Challenge Handshake Authentication Protocol] authentication.
1042 require-mschap-v2
1044 Require the peer to authenticate itself using MS-CHAPv2 [Micro‐
1045 soft Challenge Handshake Authentication Protocol, Version 2]
1046 authentication.
1047 require-eap
1049 Require the peer to authenticate itself using EAP [Extensible
1050 Authentication Protocol] authentication.
1051 require-pap
1053 Require the peer to authenticate itself using PAP [Password
1054 Authentication Protocol] authentication.
1055 set name=value
1057 Set an environment variable for scripts that are invoked by
1058 pppd. When set by a privileged source, the variable specified
1059 by name cannot be changed by options contained in an unprivi‐
1060 leged source. See also the unset option and the environment
1061 described in SCRIPTS.
1062 show-password
1064 When logging the contents of PAP packets, this option causes
1065 pppd to show the password string in the log message.
1066 silent With this option, pppd will not transmit LCP packets to initiate
1068 a connection until a valid LCP packet is received from the peer
1069 (as for the `passive' option with ancient versions of pppd).
1070 srp-interval n
1072 If this parameter is given and pppd uses EAP SRP-SHA1 to authen‐
1073 ticate the peer (i.e., is the server), then pppd will use the
1074 optional lightweight SRP rechallenge mechanism at intervals of n
1075 seconds. This option is faster than eap-interval reauthentica‐
1076 tion because it uses a hash-based mechanism and does not derive
1077 a new session key.
1078 srp-pn-secret string
1080 Set the long-term pseudonym-generating secret for the server.
1081 This value is optional and if set, needs to be known at the
1082 server (authenticator) side only, and should be different for
1083 each server (or poll of identical servers). It is used along
1084 with the current date to generate a key to encrypt and decrypt
1085 the client's identity contained in the pseudonym.
1086 srp-use-pseudonym
1088 When operating as an EAP SRP-SHA1 client, attempt to use the
1089 pseudonym stored in ~/.ppp_pseudonym first as the identity, and
1090 save in this file any pseudonym offered by the peer during
1091 authentication.
1092 sync Use synchronous HDLC serial encoding instead of asynchronous.
1094 The device used by pppd with this option must have sync support.
1095 Currently supports Microgate SyncLink adapters under Linux and
1096 FreeBSD 2.2.8 and later.
1097 unit num
1099 Sets the ppp unit number (for a ppp0 or ppp1 etc interface name)
1100 for outbound connections. If the unit is already in use a
1101 dynamically allocated number will be used.
1102 ifname string
1104 Set the ppp interface name for outbound connections. If the
1105 interface name is already in use, or if the name cannot be used
1106 for any other reason, pppd will terminate.
1107 unset name
1109 Remove a variable from the environment variable for scripts that
1110 are invoked by pppd. When specified by a privileged source, the
1111 variable name cannot be set by options contained in an unprivi‐
1112 leged source. See also the set option and the environment
1113 described in SCRIPTS.
1114 updetach
1116 With this option, pppd will detach from its controlling terminal
1117 once it has successfully established the ppp connection (to the
1118 point where the first network control protocol, usually the IP
1119 control protocol, has come up).
1120 up_sdnotify
1122 Use this option to run pppd in systemd service units of
1123 Type=notify (up_sdnotify implies nodetach). When up_sdnotify is
1124 enabled, pppd will notify systemd once it has successfully
1125 established the ppp connection (to the point where the first
1126 network control protocl, usually the IP control protocol, has
1127 come up). This option is only availble when pppd is compiled
1128 with systemd support.
1129 usehostname
1131 Enforce the use of the hostname (with domain name appended, if
1132 given) as the name of the local system for authentication pur‐
1133 poses (overrides the name option). This option is not normally
1134 needed since the name option is privileged.
1135 usepeerdns
1137 Ask the peer for up to 2 DNS server addresses. The addresses
1138 supplied by the peer (if any) are passed to the /etc/ppp/ip-up
1139 script in the environment variables DNS1 and DNS2, and the envi‐
1140 ronment variable USEPEERDNS will be set to 1. In addition, pppd
1141 will create an /var/run/ppp/resolv.conf file containing one or
1142 two nameserver lines with the address(es) supplied by the peer.
1143 user name
1145 Sets the name used for authenticating the local system to the
1146 peer to name.
1147 vj-max-slots n
1149 Sets the number of connection slots to be used by the Van Jacob‐
1150 son TCP/IP header compression and decompression code to n, which
1151 must be between 2 and 16 (inclusive).
1152 welcome script
1154 Run the executable or shell command specified by script before
1155 initiating PPP negotiation, after the connect script (if any)
1156 has completed. A value for this option from a privileged source
1157 cannot be overridden by a non-privileged user.
1158 xonxoff
1160 Use software flow control (i.e. XON/XOFF) to control the flow of
1161 data on the serial port.
1162
1164 Options can be taken from files as well as the command line. Pppd
1165 reads options from the files /etc/ppp/options, ~/.ppprc and
1166 /etc/ppp/options.ttyname (in that order) before processing the options
1167 on the command line. (In fact, the command-line options are scanned to
1168 find the terminal name before the options.ttyname file is read.) In
1169 forming the name of the options.ttyname file, the initial /dev/ is
1170 removed from the terminal name, and any remaining / characters are
1171 replaced with dots.
1172 An options file is parsed into a series of words, delimited by white‐
1174 space. Whitespace can be included in a word by enclosing the word in
1175 double-quotes ("). A backslash (\) quotes the following character. A
1176 hash (#) starts a comment, which continues until the end of the line.
1177 There is no restriction on using the file or call options within an
1178 options file.
1179
1181 pppd provides system administrators with sufficient access control that
1182 PPP access to a server machine can be provided to legitimate users
1183 without fear of compromising the security of the server or the network
1184 it's on. This control is provided through restrictions on which IP
1185 addresses the peer may use, based on its authenticated identity (if
1186 any), and through restrictions on which options a non-privileged user
1187 may use. Several of pppd's options are privileged, in particular those
1188 which permit potentially insecure configurations; these options are
1189 only accepted in files which are under the control of the system admin‐
1190 istrator, or if pppd is being run by root.
1191 The default behaviour of pppd is to allow an unauthenticated peer to
1193 use a given IP address only if the system does not already have a route
1194 to that IP address. For example, a system with a permanent connection
1195 to the wider internet will normally have a default route, and thus all
1196 peers will have to authenticate themselves in order to set up a connec‐
1197 tion. On such a system, the auth option is the default. On the other
1198 hand, a system where the PPP link is the only connection to the inter‐
1199 net will not normally have a default route, so the peer will be able to
1200 use almost any IP address without authenticating itself.
1201 As indicated above, some security-sensitive options are privileged,
1203 which means that they may not be used by an ordinary non-privileged
1204 user running a setuid-root pppd, either on the command line, in the
1205 user's ~/.ppprc file, or in an options file read using the file option.
1206 Privileged options may be used in /etc/ppp/options file or in an
1207 options file read using the call option. If pppd is being run by the
1208 root user, privileged options can be used without restriction.
1209 When opening the device, pppd uses either the invoking user's user ID
1211 or the root UID (that is, 0), depending on whether the device name was
1212 specified by the user or the system administrator. If the device name
1213 comes from a privileged source, that is, /etc/ppp/options or an options
1214 file read using the call option, pppd uses full root privileges when
1215 opening the device. Thus, by creating an appropriate file under
1216 /etc/ppp/peers, the system administrator can allow users to establish a
1217 ppp connection via a device which they would not normally have permis‐
1218 sion to access. Otherwise pppd uses the invoking user's real UID when
1219 opening the device.
1220
1222 Authentication is the process whereby one peer convinces the other of
1223 its identity. This involves the first peer sending its name to the
1224 other, together with some kind of secret information which could only
1225 come from the genuine authorized user of that name. In such an
1226 exchange, we will call the first peer the "client" and the other the
1227 "server". The client has a name by which it identifies itself to the
1228 server, and the server also has a name by which it identifies itself to
1229 the client. Generally the genuine client shares some secret (or pass‐
1230 word) with the server, and authenticates itself by proving that it
1231 knows that secret. Very often, the names used for authentication cor‐
1232 respond to the internet hostnames of the peers, but this is not essen‐
1233 tial.
1234 At present, pppd supports three authentication protocols: the Password
1236 Authentication Protocol (PAP), Challenge Handshake Authentication Pro‐
1237 tocol (CHAP), and Extensible Authentication Protocol (EAP). PAP
1238 involves the client sending its name and a cleartext password to the
1239 server to authenticate itself. In contrast, the server initiates the
1240 CHAP authentication exchange by sending a challenge to the client (the
1241 challenge packet includes the server's name). The client must respond
1242 with a response which includes its name plus a hash value derived from
1243 the shared secret and the challenge, in order to prove that it knows
1244 the secret. EAP supports CHAP-style authentication, and also includes
1245 the SRP-SHA1 mechanism, which is resistant to dictionary-based attacks
1246 and does not require a cleartext password on the server side.
1247 The PPP protocol, being symmetrical, allows both peers to require the
1249 other to authenticate itself. In that case, two separate and indepen‐
1250 dent authentication exchanges will occur. The two exchanges could use
1251 different authentication protocols, and in principle, different names
1252 could be used in the two exchanges.
1253 The default behaviour of pppd is to agree to authenticate if requested,
1255 and to not require authentication from the peer. However, pppd will
1256 not agree to authenticate itself with a particular protocol if it has
1257 no secrets which could be used to do so.
1258 Pppd stores secrets for use in authentication in secrets files
1260 (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP, MS-CHAP,
1261 MS-CHAPv2, and EAP MD5-Challenge, and /etc/ppp/srp-secrets for EAP
1262 SRP-SHA1). All secrets files have the same format. The secrets files
1263 can contain secrets for pppd to use in authenticating itself to other
1264 systems, as well as secrets for pppd to use when authenticating other
1265 systems to itself.
1266 Each line in a secrets file contains one secret. A given secret is
1268 specific to a particular combination of client and server - it can only
1269 be used by that client to authenticate itself to that server. Thus
1270 each line in a secrets file has at least 3 fields: the name of the
1271 client, the name of the server, and the secret. These fields may be
1272 followed by a list of the IP addresses that the specified client may
1273 use when connecting to the specified server.
1274 A secrets file is parsed into words as for a options file, so the
1276 client name, server name and secrets fields must each be one word, with
1277 any embedded spaces or other special characters quoted or escaped.
1278 Note that case is significant in the client and server names and in the
1279 secret.
1280 If the secret starts with an `@', what follows is assumed to be the
1282 name of a file from which to read the secret. A "*" as the client or
1283 server name matches any name. When selecting a secret, pppd takes the
1284 best match, i.e. the match with the fewest wildcards.
1285 Any following words on the same line are taken to be a list of accept‐
1287 able IP addresses for that client. If there are only 3 words on the
1288 line, or if the first word is "-", then all IP addresses are disal‐
1289 lowed. To allow any address, use "*". A word starting with "!" indi‐
1290 cates that the specified address is not acceptable. An address may be
1291 followed by "/" and a number n, to indicate a whole subnet, i.e. all
1292 addresses which have the same value in the most significant n bits. In
1293 this form, the address may be followed by a plus sign ("+") to indicate
1294 that one address from the subnet is authorized, based on the ppp net‐
1295 work interface unit number in use. In this case, the host part of the
1296 address will be set to the unit number plus one.
1297 Thus a secrets file contains both secrets for use in authenticating
1299 other hosts, plus secrets which we use for authenticating ourselves to
1300 others. When pppd is authenticating the peer (checking the peer's
1301 identity), it chooses a secret with the peer's name in the first field
1302 and the name of the local system in the second field. The name of the
1303 local system defaults to the hostname, with the domain name appended if
1304 the domain option is used. This default can be overridden with the
1305 name option, except when the usehostname option is used. (For EAP
1306 SRP-SHA1, see the srp-entry(8) utility for generating proper validator
1307 entries to be used in the "secret" field.)
1308 When pppd is choosing a secret to use in authenticating itself to the
1310 peer, it first determines what name it is going to use to identify
1311 itself to the peer. This name can be specified by the user with the
1312 user option. If this option is not used, the name defaults to the name
1313 of the local system, determined as described in the previous paragraph.
1314 Then pppd looks for a secret with this name in the first field and the
1315 peer's name in the second field. Pppd will know the name of the peer
1316 if CHAP or EAP authentication is being used, because the peer will have
1317 sent it in the challenge packet. However, if PAP is being used, pppd
1318 will have to determine the peer's name from the options specified by
1319 the user. The user can specify the peer's name directly with the
1320 remotename option. Otherwise, if the remote IP address was specified
1321 by a name (rather than in numeric form), that name will be used as the
1322 peer's name. Failing that, pppd will use the null string as the peer's
1323 name.
1324 When authenticating the peer with PAP, the supplied password is first
1326 compared with the secret from the secrets file. If the password
1327 doesn't match the secret, the password is encrypted using crypt() and
1328 checked against the secret again. Thus secrets for authenticating the
1329 peer can be stored in encrypted form if desired. If the papcrypt
1330 option is given, the first (unencrypted) comparison is omitted, for
1331 better security.
1332 Furthermore, if the login option was specified, the username and pass‐
1334 word are also checked against the system password database. Thus, the
1335 system administrator can set up the pap-secrets file to allow PPP
1336 access only to certain users, and to restrict the set of IP addresses
1337 that each user can use. Typically, when using the login option, the
1338 secret in /etc/ppp/pap-secrets would be "", which will match any pass‐
1339 word supplied by the peer. This avoids the need to have the same
1340 secret in two places.
1341 Authentication must be satisfactorily completed before IPCP (or any
1343 other Network Control Protocol) can be started. If the peer is
1344 required to authenticate itself, and fails to do so, pppd will termi‐
1345 nated the link (by closing LCP). If IPCP negotiates an unacceptable IP
1346 address for the remote host, IPCP will be closed. IP packets can only
1347 be sent or received when IPCP is open.
1348 In some cases it is desirable to allow some hosts which can't authenti‐
1350 cate themselves to connect and use one of a restricted set of IP
1351 addresses, even when the local host generally requires authentication.
1352 If the peer refuses to authenticate itself when requested, pppd takes
1353 that as equivalent to authenticating with PAP using the empty string
1354 for the username and password. Thus, by adding a line to the
1355 pap-secrets file which specifies the empty string for the client and
1356 password, it is possible to allow restricted access to hosts which
1357 refuse to authenticate themselves.
1358
1360 When IPCP negotiation is completed successfully, pppd will inform the
1361 kernel of the local and remote IP addresses for the ppp interface.
1362 This is sufficient to create a host route to the remote end of the
1363 link, which will enable the peers to exchange IP packets. Communica‐
1364 tion with other machines generally requires further modification to
1365 routing tables and/or ARP (Address Resolution Protocol) tables. In
1366 most cases the defaultroute and/or proxyarp options are sufficient for
1367 this, but in some cases further intervention is required. The
1368 /etc/ppp/ip-up script can be used for this.
1369 Sometimes it is desirable to add a default route through the remote
1371 host, as in the case of a machine whose only connection to the Internet
1372 is through the ppp interface. The defaultroute option causes pppd to
1373 create such a default route when IPCP comes up, and delete it when the
1374 link is terminated.
1375 In some cases it is desirable to use proxy ARP, for example on a server
1377 machine connected to a LAN, in order to allow other hosts to communi‐
1378 cate with the remote host. The proxyarp option causes pppd to look for
1379 a network interface on the same subnet as the remote host (an interface
1380 supporting broadcast and ARP, which is up and not a point-to-point or
1381 loopback interface). If found, pppd creates a permanent, published ARP
1382 entry with the IP address of the remote host and the hardware address
1383 of the network interface found.
1384 When the demand option is used, the interface IP addresses have already
1386 been set at the point when IPCP comes up. If pppd has not been able to
1387 negotiate the same addresses that it used to configure the interface
1388 (for example when the peer is an ISP that uses dynamic IP address
1389 assignment), pppd has to change the interface IP addresses to the nego‐
1390 tiated addresses. This may disrupt existing connections, and the use
1391 of demand dialling with peers that do dynamic IP address assignment is
1392 not recommended.
1393
1395 Multilink PPP provides the capability to combine two or more PPP links
1396 between a pair of machines into a single `bundle', which appears as a
1397 single virtual PPP link which has the combined bandwidth of the indi‐
1398 vidual links. Currently, multilink PPP is only supported under Linux.
1399 Pppd detects that the link it is controlling is connected to the same
1401 peer as another link using the peer's endpoint discriminator and the
1402 authenticated identity of the peer (if it authenticates itself). The
1403 endpoint discriminator is a block of data which is hopefully unique for
1404 each peer. Several types of data can be used, including locally-
1405 assigned strings of bytes, IP addresses, MAC addresses, randomly
1406 strings of bytes, or E-164 phone numbers. The endpoint discriminator
1407 sent to the peer by pppd can be set using the endpoint option.
1408 In some circumstances the peer may send no endpoint discriminator or a
1410 non-unique value. The bundle option adds an extra string which is
1411 added to the peer's endpoint discriminator and authenticated identity
1412 when matching up links to be joined together in a bundle. The bundle
1413 option can also be used to allow the establishment of multiple bundles
1414 between the local system and the peer. Pppd uses a TDB database in
1415 /var/run/pppd2.tdb to match up links.
1416 Assuming that multilink is enabled and the peer is willing to negotiate
1418 multilink, then when pppd is invoked to bring up the first link to the
1419 peer, it will detect that no other link is connected to the peer and
1420 create a new bundle, that is, another ppp network interface unit. When
1421 another pppd is invoked to bring up another link to the peer, it will
1422 detect the existing bundle and join its link to it.
1423 If the first link terminates (for example, because of a hangup or a
1425 received LCP terminate-request) the bundle is not destroyed unless
1426 there are no other links remaining in the bundle. Rather than exiting,
1427 the first pppd keeps running after its link terminates, until all the
1428 links in the bundle have terminated. If the first pppd receives a
1429 SIGTERM or SIGINT signal, it will destroy the bundle and send a SIGHUP
1430 to the pppd processes for each of the links in the bundle. If the
1431 first pppd receives a SIGHUP signal, it will terminate its link but not
1432 the bundle.
1433 Note: demand mode is not currently supported with multilink.
1435
1437 The following examples assume that the /etc/ppp/options file contains
1438 the auth option (as in the default /etc/ppp/options file in the ppp
1439 distribution).
1440 Probably the most common use of pppd is to dial out to an ISP. This
1442 can be done with a command such as
1443 pppd call isp
1445 where the /etc/ppp/peers/isp file is set up by the system administrator
1447 to contain something like this:
1448 ttyS0 19200 crtscts
1450 connect '/usr/sbin/chat -v -f /etc/ppp/chat-isp'
1451 noauth
1452 In this example, we are using chat to dial the ISP's modem and go
1454 through any logon sequence required. The /etc/ppp/chat-isp file con‐
1455 tains the script used by chat; it could for example contain something
1456 like this:
1457 ABORT "NO CARRIER"
1459 ABORT "NO DIALTONE"
1460 ABORT "ERROR"
1461 ABORT "NO ANSWER"
1462 ABORT "BUSY"
1463 ABORT "Username/Password Incorrect"
1464 "" "at"
1465 OK "at&d0&c1"
1466 OK "atdt2468135"
1467 "name:" "^Umyuserid"
1468 "word:" "\qmypassword"
1469 "ispts" "\q^Uppp"
1470 "~-^Uppp-~"
1471 See the chat(8) man page for details of chat scripts.
1473 Pppd can also be used to provide a dial-in ppp service for users. If
1475 the users already have login accounts, the simplest way to set up the
1476 ppp service is to let the users log in to their accounts and run pppd
1477 (installed setuid-root) with a command such as
1478 pppd proxyarp
1480 To allow a user to use the PPP facilities, you need to allocate an IP
1482 address for that user's machine and create an entry in
1483 /etc/ppp/pap-secrets, /etc/ppp/chap-secrets, or /etc/ppp/srp-secrets
1484 (depending on which authentication method the PPP implementation on the
1485 user's machine supports), so that the user's machine can authenticate
1486 itself. For example, if Joe has a machine called "joespc" that is to
1487 be allowed to dial in to the machine called "server" and use the IP
1488 address joespc.my.net, you would add an entry like this to
1489 /etc/ppp/pap-secrets or /etc/ppp/chap-secrets:
1490 joespc server "joe's secret" joespc.my.net
1492 (See srp-entry(8) for a means to generate the server's entry when
1494 SRP-SHA1 is in use.) Alternatively, you can create a username called
1495 (for example) "ppp", whose login shell is pppd and whose home directory
1496 is /etc/ppp. Options to be used when pppd is run this way can be put
1497 in /etc/ppp/.ppprc.
1498 If your serial connection is any more complicated than a piece of wire,
1500 you may need to arrange for some control characters to be escaped. In
1501 particular, it is often useful to escape XON (^Q) and XOFF (^S), using
1502 asyncmap a0000. If the path includes a telnet, you probably should
1503 escape ^] as well (asyncmap 200a0000). If the path includes an rlogin,
1504 you will need to use the escape ff option on the end which is running
1505 the rlogin client, since many rlogin implementations are not transpar‐
1506 ent; they will remove the sequence [0xff, 0xff, 0x73, 0x73, followed by
1507 any 8 bytes] from the stream.
1508
1510 Messages are sent to the syslog daemon using facility LOG_DAEMON.
1511 (This can be overridden by recompiling pppd with the macro LOG_PPP
1512 defined as the desired facility.) See the syslog(8) documentation for
1513 details of where the syslog daemon will write the messages. On most
1514 systems, the syslog daemon uses the /etc/syslog.conf file to specify
1515 the destination(s) for syslog messages. You may need to edit that file
1516 to suit.
1517 The debug option causes the contents of all control packets sent or
1519 received to be logged, that is, all LCP, PAP, CHAP, EAP, or IPCP pack‐
1520 ets. This can be useful if the PPP negotiation does not succeed or if
1521 authentication fails. If debugging is enabled at compile time, the
1522 debug option also causes other debugging messages to be logged.
1523 Debugging can also be enabled or disabled by sending a SIGUSR1 signal
1525 to the pppd process. This signal acts as a toggle.
1526
1528 The exit status of pppd is set to indicate whether any error was
1529 detected, or the reason for the link being terminated. The values used
1530 are:
1531 0 Pppd has detached, or otherwise the connection was successfully
1533 established and terminated at the peer's request.
1534 1 An immediately fatal error of some kind occurred, such as an
1536 essential system call failing, or running out of virtual memory.
1537 2 An error was detected in processing the options given, such as
1539 two mutually exclusive options being used.
1540 3 Pppd is not setuid-root and the invoking user is not root.
1542 4 The kernel does not support PPP, for example, the PPP kernel
1544 driver is not included or cannot be loaded.
1545 5 Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP
1547 signal.
1548 6 The serial port could not be locked.
1550 7 The serial port could not be opened.
1552 8 The connect script failed (returned a non-zero exit status).
1554 9 The command specified as the argument to the pty option could
1556 not be run.
1557 10 The PPP negotiation failed, that is, it didn't reach the point
1559 where at least one network protocol (e.g. IP) was running.
1560 11 The peer system failed (or refused) to authenticate itself.
1562 12 The link was established successfully and terminated because it
1564 was idle.
1565 13 The link was established successfully and terminated because the
1567 connect time limit was reached.
1568 14 Callback was negotiated and an incoming call should arrive
1570 shortly.
1571 15 The link was terminated because the peer is not responding to
1573 echo requests.
1574 16 The link was terminated by the modem hanging up.
1576 17 The PPP negotiation failed because serial loopback was detected.
1578 18 The init script failed (returned a non-zero exit status).
1580 19 We failed to authenticate ourselves to the peer.
1582
1584 Pppd invokes scripts at various stages in its processing which can be
1585 used to perform site-specific ancillary processing. These scripts are
1586 usually shell scripts, but could be executable code files instead.
1587 Pppd does not wait for the scripts to finish (except for the ip-pre-up
1588 script). The scripts are executed as root (with the real and effective
1589 user-id set to 0), so that they can do things such as update routing
1590 tables or run privileged daemons. Be careful that the contents of
1591 these scripts do not compromise your system's security. Pppd runs the
1592 scripts with standard input, output and error redirected to /dev/null,
1593 and with an environment that is empty except for some environment vari‐
1594 ables that give information about the link. The environment variables
1595 that pppd sets are:
1596 DEVICE The name of the serial tty device being used.
1598 IFNAME The name of the network interface being used.
1600 IPLOCAL
1602 The IP address for the local end of the link. This is only set
1603 when IPCP has come up.
1604 IPREMOTE
1606 The IP address for the remote end of the link. This is only set
1607 when IPCP has come up.
1608 PEERNAME
1610 The authenticated name of the peer. This is only set if the
1611 peer authenticates itself.
1612 SPEED The baud rate of the tty device.
1614 ORIG_UID
1616 The real user-id of the user who invoked pppd.
1617 PPPLOGNAME
1619 The username of the real user-id that invoked pppd. This is
1620 always set.
1621 For the ip-down and auth-down scripts, pppd also sets the following
1623 variables giving statistics for the connection:
1624 CONNECT_TIME
1626 The number of seconds from when the PPP negotiation started
1627 until the connection was terminated.
1628 BYTES_SENT
1630 The number of bytes sent (at the level of the serial port) dur‐
1631 ing the connection.
1632 BYTES_RCVD
1634 The number of bytes received (at the level of the serial port)
1635 during the connection.
1636 LINKNAME
1638 The logical name of the link, set with the linkname option.
1639 DNS1 If the peer supplies DNS server addresses, this variable is set
1641 to the first DNS server address supplied (whether or not the
1642 usepeerdns option was given).
1643 DNS2 If the peer supplies DNS server addresses, this variable is set
1645 to the second DNS server address supplied (whether or not the
1646 usepeerdns option was given).
1647 Pppd invokes the following scripts, if they exist. It is not an error
1649 if they don't exist.
1650 /etc/ppp/auth-up
1652 A program or script which is executed after the remote system
1653 successfully authenticates itself. It is executed with the
1654 parameters
1655 interface-name peer-name user-name tty-device speed
1657 Note that this script is not executed if the peer doesn't
1659 authenticate itself, for example when the noauth option is used.
1660 /etc/ppp/auth-down
1662 A program or script which is executed when the link goes down,
1663 if /etc/ppp/auth-up was previously executed. It is executed in
1664 the same manner with the same parameters as /etc/ppp/auth-up.
1665 /etc/ppp/ip-pre-up
1667 A program or script which is executed just before the ppp net‐
1668 work interface is brought up. It is executed with the same
1669 parameters as the ip-up script (below). At this point the
1670 interface exists and has IP addresses assigned but is still
1671 down. This can be used to add firewall rules before any IP
1672 traffic can pass through the interface. Pppd will wait for this
1673 script to finish before bringing the interface up, so this
1674 script should run quickly.
1675 /etc/ppp/ip-up
1677 A program or script which is executed when the link is available
1678 for sending and receiving IP packets (that is, IPCP has come
1679 up). It is executed with the parameters
1680 interface-name tty-device speed local-IP-address
1682 remote-IP-address ipparam
1683 /etc/ppp/ip-down
1685 A program or script which is executed when the link is no longer
1686 available for sending and receiving IP packets. This script can
1687 be used for undoing the effects of the /etc/ppp/ip-up and
1688 /etc/ppp/ip-pre-up scripts. It is invoked in the same manner
1689 and with the same parameters as the ip-up script.
1690 /etc/ppp/ipv6-up
1692 Like /etc/ppp/ip-up, except that it is executed when the link is
1693 available for sending and receiving IPv6 packets. It is executed
1694 with the parameters
1695 interface-name tty-device speed local-link-local-address
1697 remote-link-local-address ipparam
1698 /etc/ppp/ipv6-down
1700 Similar to /etc/ppp/ip-down, but it is executed when IPv6 pack‐
1701 ets can no longer be transmitted on the link. It is executed
1702 with the same parameters as the ipv6-up script.
1703 /etc/ppp/ipx-up
1705 A program or script which is executed when the link is available
1706 for sending and receiving IPX packets (that is, IPXCP has come
1707 up). It is executed with the parameters
1708 interface-name tty-device speed network-number
1710 local-IPX-node-address remote-IPX-node-address local-IPX-rout‐
1711 ing-protocol remote-IPX-routing-protocol local-IPX-router-name
1712 remote-IPX-router-name ipparam pppd-pid
1713 The local-IPX-routing-protocol and remote-IPX-routing-protocol
1715 field may be one of the following:
1716 NONE to indicate that there is no routing protocol
1718 RIP to indicate that RIP/SAP should be used
1719 NLSP to indicate that Novell NLSP should be used
1720 RIP NLSP to indicate that both RIP/SAP and NLSP should be used
1721 /etc/ppp/ipx-down
1723 A program or script which is executed when the link is no longer
1724 available for sending and receiving IPX packets. This script
1725 can be used for undoing the effects of the /etc/ppp/ipx-up
1726 script. It is invoked in the same manner and with the same
1727 parameters as the ipx-up script.
1728
1730 /var/run/pppn.pid (BSD or Linux), /etc/ppp/pppn.pid (others)
1731 Process-ID for pppd process on ppp interface unit n.
1732 /var/run/ppp-name.pid (BSD or Linux),
1734 /etc/ppp/ppp-name.pid (others) Process-ID for pppd process for
1735 logical link name (see the linkname option).
1736 /var/run/pppd2.tdb
1738 Database containing information about pppd processes, interfaces
1739 and links, used for matching links to bundles in multilink oper‐
1740 ation. May be examined by external programs to obtain informa‐
1741 tion about running pppd instances, the interfaces and devices
1742 they are using, IP address assignments, etc.
1743 /etc/ppp/pap-secrets Usernames, passwords and IP addresses for
1744 PAP authentication. This file should be owned by root and not
1745 readable or writable by any other user. Pppd will log a warning
1746 if this is not the case.
1747 /etc/ppp/chap-secrets
1749 Names, secrets and IP addresses for CHAP/MS-CHAP/MS-CHAPv2
1750 authentication. As for /etc/ppp/pap-secrets, this file should
1751 be owned by root and not readable or writable by any other user.
1752 Pppd will log a warning if this is not the case.
1753 /etc/ppp/srp-secrets
1755 Names, secrets, and IP addresses for EAP authentication. As for
1756 /etc/ppp/pap-secrets, this file should be owned by root and not
1757 readable or writable by any other user. Pppd will log a warning
1758 if this is not the case.
1759 ~/.ppp_pseudonym
1761 Saved client-side SRP-SHA1 pseudonym. See the srp-use-pseudonym
1762 option for details.
1763 /etc/ppp/options
1765 System default options for pppd, read before user default
1766 options or command-line options.
1767 ~/.ppprc
1769 User default options, read before /etc/ppp/options.ttyname.
1770 /etc/ppp/options.ttyname
1772 System default options for the serial port being used, read
1773 after ~/.ppprc. In forming the ttyname part of this filename,
1774 an initial /dev/ is stripped from the port name (if present),
1775 and any slashes in the remaining part are converted to dots.
1776 /etc/ppp/peers
1778 A directory containing options files which may contain privi‐
1779 leged options, even if pppd was invoked by a user other than
1780 root. The system administrator can create options files in this
1781 directory to permit non-privileged users to dial out without
1782 requiring the peer to authenticate, but only to certain trusted
1783 peers.
1784
1786 chat(8), pppstats(8)
1787 RFC1144
1789 Jacobson, V. Compressing TCP/IP headers for low-speed serial
1790 links. February 1990.
1791 RFC1321
1793 Rivest, R. The MD5 Message-Digest Algorithm. April 1992.
1794 RFC1332
1796 McGregor, G. PPP Internet Protocol Control Protocol (IPCP).
1797 May 1992.
1798 RFC1334
1800 Lloyd, B.; Simpson, W.A. PPP authentication protocols. October
1801 1992.
1802 RFC1661
1804 Simpson, W.A. The Point-to-Point Protocol (PPP). July 1994.
1805 RFC1662
1807 Simpson, W.A. PPP in HDLC-like Framing. July 1994.
1808 RFC2284
1810 Blunk, L.; Vollbrecht, J., PPP Extensible Authentication Proto‐
1811 col (EAP). March 1998.
1812 RFC2472
1814 Haskin, D. IP Version 6 over PPP December 1998.
1815 RFC2945
1817 Wu, T., The SRP Authentication and Key Exchange System September
1818 2000.
1819 draft-ietf-pppext-eap-srp-03.txt
1821 Carlson, J.; et al., EAP SRP-SHA1 Authentication Protocol. July
1822 2001.
1823
1825 Some limited degree of control can be exercised over a running pppd
1826 process by sending it a signal from the list below.
1827 SIGINT, SIGTERM
1829 These signals cause pppd to terminate the link (by closing LCP),
1830 restore the serial device settings, and exit. If a connector or
1831 disconnector process is currently running, pppd will send the
1832 same signal to its process group, so as to terminate the connec‐
1833 tor or disconnector process.
1834 SIGHUP This signal causes pppd to terminate the link, restore the
1836 serial device settings, and close the serial device. If the
1837 persist or demand option has been specified, pppd will try to
1838 reopen the serial device and start another connection (after the
1839 holdoff period). Otherwise pppd will exit. If this signal is
1840 received during the holdoff period, it causes pppd to end the
1841 holdoff period immediately. If a connector or disconnector
1842 process is running, pppd will send the same signal to its
1843 process group.
1844 SIGUSR1
1846 This signal toggles the state of the debug option.
1847 SIGUSR2
1849 This signal causes pppd to renegotiate compression. This can be
1850 useful to re-enable compression after it has been disabled as a
1851 result of a fatal decompression error. (Fatal decompression
1852 errors generally indicate a bug in one or other implementation.)
1853
1856 Paul Mackerras (paulus@samba.org), based on earlier work by Drew
1857 Perkins, Brad Clements, Karl Fox, Greg Christy, and Brad Parker.
1858
1861 Pppd is copyrighted and made available under conditions which provide
1862 that it may be copied and used in source or binary forms provided that
1863 the conditions listed below are met. Portions of pppd are covered by
1864 the following copyright notices:
1865 Copyright (c) 1984-2000 Carnegie Mellon University. All rights
1867 reserved.
1868 Copyright (c) 1993-2004 Paul Mackerras. All rights reserved.
1869 Copyright (c) 1995 Pedro Roque Marques. All rights reserved.
1870 Copyright (c) 1995 Eric Rosenquist. All rights reserved.
1871 Copyright (c) 1999 Tommi Komulainen. All rights reserved.
1872 Copyright (C) Andrew Tridgell 1999
1873 Copyright (c) 2000 by Sun Microsystems, Inc. All rights reserved.
1874 Copyright (c) 2001 by Sun Microsystems, Inc. All rights reserved.
1875 Copyright (c) 2002 Google, Inc. All rights reserved.
1876 The copyright notices contain the following statements.
1878 Redistribution and use in source and binary forms, with or without mod‐
1880 ification, are permitted provided that the following conditions are
1881 met:
1882 1. Redistributions of source code must retain the above copyright
1884 notice, this list of conditions and the following disclaimer.
1885 2. Redistributions in binary form must reproduce the above copyright
1887 notice, this list of conditions and the following disclaimer in
1888 the documentation and/or other materials provided with the
1889 distribution.
1890 3. The name "Carnegie Mellon University" must not be used to
1892 endorse or promote products derived from this software without
1893 prior written permission. For permission or any legal
1894 details, please contact
1895 Office of Technology Transfer
1896 Carnegie Mellon University
1897 5000 Forbes Avenue
1898 Pittsburgh, PA 15213-3890
1899 (412) 268-4387, fax: (412) 268-7395
1900 tech-transfer@andrew.cmu.edu
1901 3b. The name(s) of the authors of this software must not be used to
1903 endorse or promote products derived from this software without
1904 prior written permission.
1905 4. Redistributions of any form whatsoever must retain the following
1907 acknowledgements:
1908 "This product includes software developed by Computing Services
1909 at Carnegie Mellon University (http://www.cmu.edu/computing/)."
1910 "This product includes software developed by Paul Mackerras
1911 <paulus@samba.org>".
1912 "This product includes software developed by Pedro Roque Marques
1913 <pedro_m@yahoo.com>".
1914 "This product includes software developed by Tommi Komulainen
1915 <Tommi.Komulainen@iki.fi>".
1916 CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
1918 SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FIT‐
1919 NESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE FOR ANY
1920 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
1921 RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
1922 CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
1923 CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
1924 THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
1926 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
1927 FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDI‐
1928 RECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
1929 LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLI‐
1930 GENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH
1931 THE USE OR PERFORMANCE OF THIS SOFTWARE.
1932 PPPD(8)