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 disconnect script
99 Execute the command specified by script, by passing it to a
100 shell, after pppd has terminated the link. This command could,
101 for example, issue commands to the modem to cause it to hang up
102 if hardware modem control signals were not available. The dis‐
103 connect script is not run if the modem has already hung up. A
104 value for this option from a privileged source cannot be over‐
105 ridden by a non-privileged user.
106 escape xx,yy,...
108 Specifies that certain characters should be escaped on transmis‐
109 sion (regardless of whether the peer requests them to be escaped
110 with its async control character map). The characters to be
111 escaped are specified as a list of hex numbers separated by com‐
112 mas. Note that almost any character can be specified for the
113 escape option, unlike the asyncmap option which only allows con‐
114 trol characters to be specified. The characters which may not
115 be escaped are those with hex values 0x20 - 0x3f or 0x5e.
116 file name
118 Read options from file name (the format is described below).
119 The file must be readable by the user who has invoked pppd.
120 init script
122 Execute the command specified by script, by passing it to a
123 shell, to initialize the serial line. This script would typi‐
124 cally use the chat(8) program to configure the modem to enable
125 auto answer. A value for this option from a privileged source
126 cannot be overridden by a non-privileged user.
127 lock Specifies that pppd should create a UUCP-style lock file for the
129 serial device to ensure exclusive access to the device. By
130 default, pppd will not create a lock file.
131 mru n Set the MRU [Maximum Receive Unit] value to n. Pppd will ask the
133 peer to send packets of no more than n bytes. The value of n
134 must be between 128 and 16384; the default is 1500. A value of
135 296 works well on very slow links (40 bytes for TCP/IP header +
136 256 bytes of data). Note that for the IPv6 protocol, the MRU
137 must be at least 1280.
138 mtu n Set the MTU [Maximum Transmit Unit] value to n. Unless the peer
140 requests a smaller value via MRU negotiation, pppd will request
141 that the kernel networking code send data packets of no more
142 than n bytes through the PPP network interface. Note that for
143 the IPv6 protocol, the MTU must be at least 1280.
144 passive
146 Enables the "passive" option in the LCP. With this option, pppd
147 will attempt to initiate a connection; if no reply is received
148 from the peer, pppd will then just wait passively for a valid
149 LCP packet from the peer, instead of exiting, as it would with‐
150 out this option.
151
153 <local_IP_address>:<remote_IP_address>
154 Set the local and/or remote interface IP addresses. Either one
155 may be omitted. The IP addresses can be specified with a host
156 name or in decimal dot notation (e.g. 150.234.56.78). The
157 default local address is the (first) IP address of the system
158 (unless the noipdefault option is given). The remote address
159 will be obtained from the peer if not specified in any option.
160 Thus, in simple cases, this option is not required. If a local
161 and/or remote IP address is specified with this option, pppd
162 will not accept a different value from the peer in the IPCP
163 negotiation, unless the ipcp-accept-local and/or
164 ipcp-accept-remote options are given, respectively.
165 +ipv6 Enable the IPv6CP and IPv6 protocols.
167 ipv6 <local_interface_identifier>,<remote_interface_identifier>
169 Set the local and/or remote 64-bit interface identifier. Either
170 one may be omitted. The identifier must be specified in standard
171 ASCII notation of IPv6 addresses (e.g. ::dead:beef). If the
172 ipv6cp-use-ipaddr option is given, the local identifier is the
173 local IPv4 address (see above). On systems which supports a
174 unique persistent id, such as EUI-48 derived from the Ethernet
175 MAC address, ipv6cp-use-persistent option can be used to replace
176 the ipv6 <local>,<remote> option. Otherwise the identifier is
177 randomized.
178 active-filter filter-expression
180 Specifies a packet filter to be applied to data packets to
181 determine which packets are to be regarded as link activity, and
182 therefore reset the idle timer, or cause the link to be brought
183 up in demand-dialling mode. This option is useful in conjunc‐
184 tion with the idle option if there are packets being sent or
185 received regularly over the link (for example, routing informa‐
186 tion packets) which would otherwise prevent the link from ever
187 appearing to be idle. The filter-expression syntax is as
188 described for tcpdump(1), except that qualifiers which are inap‐
189 propriate for a PPP link, such as ether and arp, are not permit‐
190 ted. Generally the filter expression should be enclosed in sin‐
191 gle-quotes to prevent whitespace in the expression from being
192 interpreted by the shell. This option is currently only avail‐
193 able under Linux, and requires that the kernel was configured to
194 include PPP filtering support (CONFIG_PPP_FILTER). Note that it
195 is possible to apply different constraints to incoming and out‐
196 going packets using the inbound and outbound qualifiers.
197 allow-ip address(es)
199 Allow peers to use the given IP address or subnet without
200 authenticating themselves. The parameter is parsed as for each
201 element of the list of allowed IP addresses in the secrets files
202 (see the AUTHENTICATION section below).
203 allow-number number
205 Allow peers to connect from the given telephone number. A
206 trailing `*' character will match all numbers beginning with the
207 leading part.
208 bsdcomp nr,nt
210 Request that the peer compress packets that it sends, using the
211 BSD-Compress scheme, with a maximum code size of nr bits, and
212 agree to compress packets sent to the peer with a maximum code
213 size of nt bits. If nt is not specified, it defaults to the
214 value given for nr. Values in the range 9 to 15 may be used for
215 nr and nt; larger values give better compression but consume
216 more kernel memory for compression dictionaries. Alternatively,
217 a value of 0 for nr or nt disables compression in the corre‐
218 sponding direction. Use nobsdcomp or bsdcomp 0 to disable BSD-
219 Compress compression entirely.
220 ca ca-file
222 (EAP-TLS) Use the file ca-file as the X.509 Certificate Author‐
223 ity (CA) file (in PEM format), needed for setting up an EAP-TLS
224 connection. This option is used on the client-side in conjunc‐
225 tion with the cert and key options.
226 cdtrcts
228 Use a non-standard hardware flow control (i.e. DTR/CTS) to con‐
229 trol the flow of data on the serial port. If neither the
230 crtscts, the nocrtscts, the cdtrcts nor the nocdtrcts option is
231 given, the hardware flow control setting for the serial port is
232 left unchanged. Some serial ports (such as Macintosh serial
233 ports) lack a true RTS output. Such serial ports use this mode
234 to implement true bi-directional flow control. The sacrifice is
235 that this flow control mode does not permit using DTR as a modem
236 control line.
237 cert certfile
239 (EAP-TLS) Use the file certfile as the X.509 certificate (in PEM
240 format), needed for setting up an EAP-TLS connection. This
241 option is used on the client-side in conjunction with the ca and
242 key options.
243 chap-interval n
245 If this option is given, pppd will rechallenge the peer every n
246 seconds.
247 chap-max-challenge n
249 Set the maximum number of CHAP challenge transmissions to n
250 (default 10).
251 chap-restart n
253 Set the CHAP restart interval (retransmission timeout for chal‐
254 lenges) to n seconds (default 3).
255 child-timeout n
257 When exiting, wait for up to n seconds for any child processes
258 (such as the command specified with the pty command) to exit
259 before exiting. At the end of the timeout, pppd will send a
260 SIGTERM signal to any remaining child processes and exit. A
261 value of 0 means no timeout, that is, pppd will wait until all
262 child processes have exited.
263 connect-delay n
265 Wait for up to n milliseconds after the connect script finishes
266 for a valid PPP packet from the peer. At the end of this time,
267 or when a valid PPP packet is received from the peer, pppd will
268 commence negotiation by sending its first LCP packet. The
269 default value is 1000 (1 second). This wait period only applies
270 if the connect or pty option is used.
271 crl filename
273 (EAP-TLS) Use the file filename as the Certificate Revocation
274 List to check for the validity of the peer's certificate. This
275 option is not mandatory for setting up an EAP-TLS connection.
276 Also see the crl-dir option.
277 crl-dir directory
279 (EAP-TLS) Use the directory directory to scan for CRL files in
280 has format ($hash.r0) to check for the validity of the peer's
281 certificate. This option is not mandatory for setting up an
282 EAP-TLS connection. Also see the crl option.
283 debug Enables connection debugging facilities. If this option is
285 given, pppd will log the contents of all control packets sent or
286 received in a readable form. The packets are logged through
287 syslog with facility daemon and level debug. This information
288 can be directed to a file by setting up /etc/syslog.conf appro‐
289 priately (see syslog.conf(5)).
290 default-asyncmap
292 Disable asyncmap negotiation, forcing all control characters to
293 be escaped for both the transmit and the receive direction.
294 default-mru
296 Disable MRU [Maximum Receive Unit] negotiation. With this
297 option, pppd will use the default MRU value of 1500 bytes for
298 both the transmit and receive direction.
299 deflate nr,nt
301 Request that the peer compress packets that it sends, using the
302 Deflate scheme, with a maximum window size of 2**nr bytes, and
303 agree to compress packets sent to the peer with a maximum window
304 size of 2**nt bytes. If nt is not specified, it defaults to the
305 value given for nr. Values in the range 9 to 15 may be used for
306 nr and nt; larger values give better compression but consume
307 more kernel memory for compression dictionaries. Alternatively,
308 a value of 0 for nr or nt disables compression in the corre‐
309 sponding direction. Use nodeflate or deflate 0 to disable
310 Deflate compression entirely. (Note: pppd requests Deflate com‐
311 pression in preference to BSD-Compress if the peer can do
312 either.)
313 demand Initiate the link only on demand, i.e. when data traffic is
315 present. With this option, the remote IP address may be speci‐
316 fied by the user on the command line or in an options file, or
317 if not, pppd will use an arbitrary address in the 10.x.x.x
318 range. Pppd will initially configure the interface and enable
319 it for IP traffic without connecting to the peer. When traffic
320 is available, pppd will connect to the peer and perform negotia‐
321 tion, authentication, etc. When this is completed, pppd will
322 commence passing data packets (i.e., IP packets) across the
323 link.
324 The demand option implies the persist option. If this behaviour
326 is not desired, use the nopersist option after the demand
327 option. The idle and holdoff options are also useful in con‐
328 junction with the demand option.
329 domain d
331 Append the domain name d to the local host name for authentica‐
332 tion purposes. For example, if gethostname() returns the name
333 porsche, but the fully qualified domain name is
334 porsche.Quotron.COM, you could specify domain Quotron.COM. Pppd
335 would then use the name porsche.Quotron.COM for looking up
336 secrets in the secrets file, and as the default name to send to
337 the peer when authenticating itself to the peer. This option is
338 privileged.
339 dryrun With the dryrun option, pppd will print out all the option val‐
341 ues which have been set and then exit, after parsing the command
342 line and options files and checking the option values, but
343 before initiating the link. The option values are logged at
344 level info, and also printed to standard output unless the
345 device on standard output is the device that pppd would be using
346 to communicate with the peer.
347 dump With the dump option, pppd will print out all the option values
349 which have been set. This option is like the dryrun option
350 except that pppd proceeds as normal rather than exiting.
351 enable-session
353 Enables session accounting via PAM or wtwp/wtmpx, as appropri‐
354 ate. When PAM is enabled, the PAM "account" and "session" mod‐
355 ule stacks determine behavior, and are enabled for all PPP
356 authentication protocols. When PAM is disabled, wtmp/wtmpx
357 entries are recorded regardless of whether the peer name identi‐
358 fies a valid user on the local system, making peers visible in
359 the last(1) log. This feature is automatically enabled when the
360 pppd login option is used. Session accounting is disabled by
361 default.
362 endpoint <epdisc>
364 Sets the endpoint discriminator sent by the local machine to the
365 peer during multilink negotiation to <epdisc>. The default is
366 to use the MAC address of the first ethernet interface on the
367 system, if any, otherwise the IPv4 address corresponding to the
368 hostname, if any, provided it is not in the multicast or
369 locally-assigned IP address ranges, or the localhost address.
370 The endpoint discriminator can be the string null or of the form
371 type:value, where type is a decimal number or one of the strings
372 local, IP, MAC, magic, or phone. The value is an IP address in
373 dotted-decimal notation for the IP type, or a string of bytes in
374 hexadecimal, separated by periods or colons for the other types.
375 For the MAC type, the value may also be the name of an ethernet
376 or similar network interface. This option is currently only
377 available under Linux.
378 eap-interval n
380 If this option is given and pppd authenticates the peer with EAP
381 (i.e., is the server), pppd will restart EAP authentication
382 every n seconds. For EAP SRP-SHA1, see also the srp-interval
383 option, which enables lightweight rechallenge.
384 eap-max-rreq n
386 Set the maximum number of EAP Requests to which pppd will
387 respond (as a client) without hearing EAP Success or Failure.
388 (Default is 20.)
389 eap-max-sreq n
391 Set the maximum number of EAP Requests that pppd will issue (as
392 a server) while attempting authentication. (Default is 10.)
393 eap-restart n
395 Set the retransmit timeout for EAP Requests when acting as a
396 server (authenticator). (Default is 3 seconds.)
397 eap-timeout n
399 Set the maximum time to wait for the peer to send an EAP Request
400 when acting as a client (authenticatee). (Default is 20 sec‐
401 onds.)
402 hide-password
404 When logging the contents of PAP packets, this option causes
405 pppd to exclude the password string from the log. This is the
406 default.
407 holdoff n
409 Specifies how many seconds to wait before re-initiating the link
410 after it terminates. This option only has any effect if the
411 persist or demand option is used. The holdoff period is not
412 applied if the link was terminated because it was idle.
413 idle n Specifies that pppd should disconnect if the link is idle for n
415 seconds. The link is idle when no data packets (i.e. IP pack‐
416 ets) are being sent or received. Note: it is not advisable to
417 use this option with the persist option without the demand
418 option. If the active-filter option is given, data packets
419 which are rejected by the specified activity filter also count
420 as the link being idle.
421 ipcp-accept-local
423 With this option, pppd will accept the peer's idea of our local
424 IP address, even if the local IP address was specified in an
425 option.
426 ipcp-accept-remote
428 With this option, pppd will accept the peer's idea of its
429 (remote) IP address, even if the remote IP address was specified
430 in an option.
431 ipcp-max-configure n
433 Set the maximum number of IPCP configure-request transmissions
434 to n (default 10).
435 ipcp-max-failure n
437 Set the maximum number of IPCP configure-NAKs returned before
438 starting to send configure-Rejects instead to n (default 10).
439 ipcp-max-terminate n
441 Set the maximum number of IPCP terminate-request transmissions
442 to n (default 3).
443 ipcp-restart n
445 Set the IPCP restart interval (retransmission timeout) to n sec‐
446 onds (default 3).
447 ipparam string
449 Provides an extra parameter to the ip-up, ip-pre-up and ip-down
450 scripts. If this option is given, the string supplied is given
451 as the 6th parameter to those scripts.
452 ipv6cp-accept-local
454 With this option, pppd will accept the peer's idea of our local
455 IPv6 interface identifier, even if the local IPv6 interface
456 identifier was specified in an option.
457 ipv6cp-max-configure n
459 Set the maximum number of IPv6CP configure-request transmissions
460 to n (default 10).
461 ipv6cp-max-failure n
463 Set the maximum number of IPv6CP configure-NAKs returned before
464 starting to send configure-Rejects instead to n (default 10).
465 ipv6cp-max-terminate n
467 Set the maximum number of IPv6CP terminate-request transmissions
468 to n (default 3).
469 ipv6cp-restart n
471 Set the IPv6CP restart interval (retransmission timeout) to n
472 seconds (default 3).
473 ipx Enable the IPXCP and IPX protocols. This option is presently
475 only supported under Linux, and only if your kernel has been
476 configured to include IPX support.
477 ipx-network n
479 Set the IPX network number in the IPXCP configure request frame
480 to n, a hexadecimal number (without a leading 0x). There is no
481 valid default. If this option is not specified, the network
482 number is obtained from the peer. If the peer does not have the
483 network number, the IPX protocol will not be started.
484 ipx-node n:m
486 Set the IPX node numbers. The two node numbers are separated
487 from each other with a colon character. The first number n is
488 the local node number. The second number m is the peer's node
489 number. Each node number is a hexadecimal number, at most 10
490 digits long. The node numbers on the ipx-network must be unique.
491 There is no valid default. If this option is not specified then
492 the node numbers are obtained from the peer.
493 ipx-router-name <string>
495 Set the name of the router. This is a string and is sent to the
496 peer as information data.
497 ipx-routing n
499 Set the routing protocol to be received by this option. More
500 than one instance of ipx-routing may be specified. The 'none'
501 option (0) may be specified as the only instance of ipx-routing.
502 The values may be 0 for NONE, 2 for RIP/SAP, and 4 for NLSP.
503 ipxcp-accept-local
505 Accept the peer's NAK for the node number specified in the
506 ipx-node option. If a node number was specified, and non-zero,
507 the default is to insist that the value be used. If you include
508 this option then you will permit the peer to override the entry
509 of the node number.
510 ipxcp-accept-network
512 Accept the peer's NAK for the network number specified in the
513 ipx-network option. If a network number was specified, and non-
514 zero, the default is to insist that the value be used. If you
515 include this option then you will permit the peer to override
516 the entry of the node number.
517 ipxcp-accept-remote
519 Use the peer's network number specified in the configure request
520 frame. If a node number was specified for the peer and this
521 option was not specified, the peer will be forced to use the
522 value which you have specified.
523 ipxcp-max-configure n
525 Set the maximum number of IPXCP configure request frames which
526 the system will send to n. The default is 10.
527 ipxcp-max-failure n
529 Set the maximum number of IPXCP NAK frames which the local sys‐
530 tem will send before it rejects the options. The default value
531 is 3.
532 ipxcp-max-terminate n
534 Set the maximum number of IPXCP terminate request frames before
535 the local system considers that the peer is not listening to
536 them. The default value is 3.
537 kdebug n
539 Enable debugging code in the kernel-level PPP driver. The argu‐
540 ment values depend on the specific kernel driver, but in general
541 a value of 1 will enable general kernel debug messages. (Note
542 that these messages are usually only useful for debugging the
543 kernel driver itself.) For the Linux 2.2.x kernel driver, the
544 value is a sum of bits: 1 to enable general debug messages, 2 to
545 request that the contents of received packets be printed, and 4
546 to request that the contents of transmitted packets be printed.
547 On most systems, messages printed by the kernel are logged by
548 syslog(1) to a file as directed in the /etc/syslog.conf configu‐
549 ration file.
550 key keyfile
552 (EAP-TLS) Use the file keyfile as the private key file (in PEM
553 format), needed for setting up an EAP-TLS connection. This
554 option is used on the client-side in conjunction with the ca and
555 cert options.
556 ktune Enables pppd to alter kernel settings as appropriate. Under
558 Linux, pppd will enable IP forwarding (i.e. set
559 /proc/sys/net/ipv4/ip_forward to 1) if the proxyarp option is
560 used, and will enable the dynamic IP address option (i.e. set
561 /proc/sys/net/ipv4/ip_dynaddr to 1) in demand mode if the local
562 address changes.
563 lcp-echo-failure n
565 If this option is given, pppd will presume the peer to be dead
566 if n LCP echo-requests are sent without receiving a valid LCP
567 echo-reply. If this happens, pppd will terminate the connec‐
568 tion. Use of this option requires a non-zero value for the
569 lcp-echo-interval parameter. This option can be used to enable
570 pppd to terminate after the physical connection has been broken
571 (e.g., the modem has hung up) in situations where no hardware
572 modem control lines are available.
573 lcp-echo-interval n
575 If this option is given, pppd will send an LCP echo-request
576 frame to the peer every n seconds. Normally the peer should
577 respond to the echo-request by sending an echo-reply. This
578 option can be used with the lcp-echo-failure option to detect
579 that the peer is no longer connected.
580 lcp-max-configure n
582 Set the maximum number of LCP configure-request transmissions to
583 n (default 10).
584 lcp-max-failure n
586 Set the maximum number of LCP configure-NAKs returned before
587 starting to send configure-Rejects instead to n (default 10).
588 lcp-max-terminate n
590 Set the maximum number of LCP terminate-request transmissions to
591 n (default 3).
592 lcp-restart n
594 Set the LCP restart interval (retransmission timeout) to n sec‐
595 onds (default 3).
596 linkname name
598 Sets the logical name of the link to name. Pppd will create a
599 file named ppp-name.pid in /var/run (or /etc/ppp on some sys‐
600 tems) containing its process ID. This can be useful in deter‐
601 mining which instance of pppd is responsible for the link to a
602 given peer system. This is a privileged option.
603 local Don't use the modem control lines. With this option, pppd will
605 ignore the state of the CD (Carrier Detect) signal from the
606 modem and will not change the state of the DTR (Data Terminal
607 Ready) signal. This is the opposite of the modem option.
608 logfd n
610 Send log messages to file descriptor n. Pppd will send log mes‐
611 sages to at most one file or file descriptor (as well as sending
612 the log messages to syslog), so this option and the logfile
613 option are mutually exclusive. The default is for pppd to send
614 log messages to stdout (file descriptor 1), unless the serial
615 port is already open on stdout.
616 logfile filename
618 Append log messages to the file filename (as well as sending the
619 log messages to syslog). The file is opened with the privileges
620 of the user who invoked pppd, in append mode.
621 login Use the system password database for authenticating the peer
623 using PAP, and record the user in the system wtmp file. Note
624 that the peer must have an entry in the /etc/ppp/pap-secrets
625 file as well as the system password database to be allowed
626 access. See also the enable-session option.
627 master_detach
629 If multilink is enabled and this pppd process is the multilink
630 bundle master, and the link controlled by this pppd process ter‐
631 minates, this pppd process continues to run in order to maintain
632 the bundle. If the master_detach option has been given, pppd
633 will detach from its controlling terminal in this situation,
634 even if the nodetach option has been given.
635 maxconnect n
637 Terminate the connection when it has been available for network
638 traffic for n seconds (i.e. n seconds after the first network
639 control protocol comes up).
640 maxfail n
642 Terminate after n consecutive failed connection attempts. A
643 value of 0 means no limit. The default value is 10.
644 modem Use the modem control lines. This option is the default. With
646 this option, pppd will wait for the CD (Carrier Detect) signal
647 from the modem to be asserted when opening the serial device
648 (unless a connect script is specified), and it will drop the DTR
649 (Data Terminal Ready) signal briefly when the connection is ter‐
650 minated and before executing the connect script. On Ultrix,
651 this option implies hardware flow control, as for the crtscts
652 option. This is the opposite of the local option.
653 mp Enables the use of PPP multilink; this is an alias for the `mul‐
655 tilink' option. This option is currently only available under
656 Linux.
657 mppe-stateful
659 Allow MPPE to use stateful mode. Stateless mode is still
660 attempted first. The default is to disallow stateful mode.
661 mpshortseq
663 Enables the use of short (12-bit) sequence numbers in multilink
664 headers, as opposed to 24-bit sequence numbers. This option is
665 only available under Linux, and only has any effect if multilink
666 is enabled (see the multilink option).
667 mrru n Sets the Maximum Reconstructed Receive Unit to n. The MRRU is
669 the maximum size for a received packet on a multilink bundle,
670 and is analogous to the MRU for the individual links. This
671 option is currently only available under Linux, and only has any
672 effect if multilink is enabled (see the multilink option).
673 ms-dns <addr>
675 If pppd is acting as a server for Microsoft Windows clients,
676 this option allows pppd to supply one or two DNS (Domain Name
677 Server) addresses to the clients. The first instance of this
678 option specifies the primary DNS address; the second instance
679 (if given) specifies the secondary DNS address. (This option
680 was present in some older versions of pppd under the name
681 dns-addr.)
682 ms-wins <addr>
684 If pppd is acting as a server for Microsoft Windows or "Samba"
685 clients, this option allows pppd to supply one or two WINS (Win‐
686 dows Internet Name Services) server addresses to the clients.
687 The first instance of this option specifies the primary WINS
688 address; the second instance (if given) specifies the secondary
689 WINS address.
690 multilink
692 Enables the use of the PPP multilink protocol. If the peer also
693 supports multilink, then this link can become part of a bundle
694 between the local system and the peer. If there is an existing
695 bundle to the peer, pppd will join this link to that bundle,
696 otherwise pppd will create a new bundle. See the MULTILINK sec‐
697 tion below. This option is currently only available under
698 Linux.
699 name name
701 Set the name of the local system for authentication purposes to
702 name. This is a privileged option. With this option, pppd will
703 use lines in the secrets files which have name as the second
704 field when looking for a secret to use in authenticating the
705 peer. In addition, unless overridden with the user option, name
706 will be used as the name to send to the peer when authenticating
707 the local system to the peer. (Note that pppd does not append
708 the domain name to name.)
709 noaccomp
711 Disable Address/Control compression in both directions (send and
712 receive).
713 need-peer-eap
715 (EAP-TLS) Require the peer to verify our authentication creden‐
716 tials.
717 noauth Do not require the peer to authenticate itself. This option is
719 privileged.
720 nobsdcomp
722 Disables BSD-Compress compression; pppd will not request or
723 agree to compress packets using the BSD-Compress scheme.
724 noccp Disable CCP (Compression Control Protocol) negotiation. This
726 option should only be required if the peer is buggy and gets
727 confused by requests from pppd for CCP negotiation.
728 nocrtscts
730 Disable hardware flow control (i.e. RTS/CTS) on the serial port.
731 If neither the crtscts nor the nocrtscts nor the cdtrcts nor the
732 nocdtrcts option is given, the hardware flow control setting for
733 the serial port is left unchanged.
734 nocdtrcts
736 This option is a synonym for nocrtscts. Either of these options
737 will disable both forms of hardware flow control.
738 nodefaultroute
740 Disable the defaultroute option. The system administrator who
741 wishes to prevent users from creating default routes with pppd
742 can do so by placing this option in the /etc/ppp/options file.
743 nodeflate
745 Disables Deflate compression; pppd will not request or agree to
746 compress packets using the Deflate scheme.
747 nodetach
749 Don't detach from the controlling terminal. Without this
750 option, if a serial device other than the terminal on the stan‐
751 dard input is specified, pppd will fork to become a background
752 process.
753 noendpoint
755 Disables pppd from sending an endpoint discriminator to the peer
756 or accepting one from the peer (see the MULTILINK section
757 below). This option should only be required if the peer is
758 buggy.
759 noip Disable IPCP negotiation and IP communication. This option
761 should only be required if the peer is buggy and gets confused
762 by requests from pppd for IPCP negotiation.
763 noipv6 Disable IPv6CP negotiation and IPv6 communication. This option
765 should only be required if the peer is buggy and gets confused
766 by requests from pppd for IPv6CP negotiation.
767 noipdefault
769 Disables the default behaviour when no local IP address is spec‐
770 ified, which is to determine (if possible) the local IP address
771 from the hostname. With this option, the peer will have to sup‐
772 ply the local IP address during IPCP negotiation (unless it
773 specified explicitly on the command line or in an options file).
774 noipx Disable the IPXCP and IPX protocols. This option should only be
776 required if the peer is buggy and gets confused by requests from
777 pppd for IPXCP negotiation.
778 noktune
780 Opposite of the ktune option; disables pppd from changing system
781 settings.
782 nolock Opposite of the lock option; specifies that pppd should not cre‐
784 ate a UUCP-style lock file for the serial device. This option
785 is privileged.
786 nolog Do not send log messages to a file or file descriptor. This
788 option cancels the logfd and logfile options.
789 nomagic
791 Disable magic number negotiation. With this option, pppd cannot
792 detect a looped-back line. This option should only be needed if
793 the peer is buggy.
794 nomp Disables the use of PPP multilink. This option is currently
796 only available under Linux.
797 nomppe Disables MPPE (Microsoft Point to Point Encryption). This is
799 the default.
800 nomppe-40
802 Disable 40-bit encryption with MPPE.
803 nomppe-128
805 Disable 128-bit encryption with MPPE.
806 nomppe-stateful
808 Disable MPPE stateful mode. This is the default.
809 nompshortseq
811 Disables the use of short (12-bit) sequence numbers in the PPP
812 multilink protocol, forcing the use of 24-bit sequence numbers.
813 This option is currently only available under Linux, and only
814 has any effect if multilink is enabled.
815 nomultilink
817 Disables the use of PPP multilink. This option is currently
818 only available under Linux.
819 nopcomp
821 Disable protocol field compression negotiation in both the
822 receive and the transmit direction.
823 nopersist
825 Exit once a connection has been made and terminated. This is
826 the default unless the persist or demand option has been speci‐
827 fied.
828 nopredictor1
830 Do not accept or agree to Predictor-1 compression.
831 noproxyarp
833 Disable the proxyarp option. The system administrator who
834 wishes to prevent users from creating proxy ARP entries with
835 pppd can do so by placing this option in the /etc/ppp/options
836 file.
837 noremoteip
839 Allow pppd to operate without having an IP address for the peer.
840 This option is only available under Linux. Normally, pppd will
841 request the peer's IP address, and if the peer does not supply
842 it, pppd will use an arbitrary address in the 10.x.x.x subnet.
843 With this option, if the peer does not supply its IP address,
844 pppd will not ask the peer for it, and will not set the destina‐
845 tion address of the ppp interface. In this situation, the ppp
846 interface can be used for routing by creating device routes, but
847 the peer itself cannot be addressed directly for IP traffic.
848 notty Normally, pppd requires a terminal device. With this option,
850 pppd will allocate itself a pseudo-tty master/slave pair and use
851 the slave as its terminal device. Pppd will create a child
852 process to act as a `character shunt' to transfer characters
853 between the pseudo-tty master and its standard input and output.
854 Thus pppd will transmit characters on its standard output and
855 receive characters on its standard input even if they are not
856 terminal devices. This option increases the latency and CPU
857 overhead of transferring data over the ppp interface as all of
858 the characters sent and received must flow through the character
859 shunt process. An explicit device name may not be given if this
860 option is used.
861 novj Disable Van Jacobson style TCP/IP header compression in both the
863 transmit and the receive direction.
864 novjccomp
866 Disable the connection-ID compression option in Van Jacobson
867 style TCP/IP header compression. With this option, pppd will
868 not omit the connection-ID byte from Van Jacobson compressed
869 TCP/IP headers, nor ask the peer to do so.
870 papcrypt
872 Indicates that all secrets in the /etc/ppp/pap-secrets file
873 which are used for checking the identity of the peer are
874 encrypted, and thus pppd should not accept a password which,
875 before encryption, is identical to the secret from the
876 /etc/ppp/pap-secrets file.
877 pap-max-authreq n
879 Set the maximum number of PAP authenticate-request transmissions
880 to n (default 10).
881 pap-restart n
883 Set the PAP restart interval (retransmission timeout) to n sec‐
884 onds (default 3).
885 pap-timeout n
887 Set the maximum time that pppd will wait for the peer to authen‐
888 ticate itself with PAP to n seconds (0 means no limit).
889 pass-filter filter-expression
891 Specifies a packet filter to applied to data packets being sent
892 or received to determine which packets should be allowed to
893 pass. Packets which are rejected by the filter are silently
894 discarded. This option can be used to prevent specific network
895 daemons (such as routed) using up link bandwidth, or to provide
896 a very basic firewall capability. The filter-expression syntax
897 is as described for tcpdump(1), except that qualifiers which are
898 inappropriate for a PPP link, such as ether and arp, are not
899 permitted. Generally the filter expression should be enclosed
900 in single-quotes to prevent whitespace in the expression from
901 being interpreted by the shell. Note that it is possible to
902 apply different constraints to incoming and outgoing packets
903 using the inbound and outbound qualifiers. This option is cur‐
904 rently only available under Linux, and requires that the kernel
905 was configured to include PPP filtering support (CONFIG_PPP_FIL‐
906 TER).
907 password password-string
909 Specifies the password to use for authenticating to the peer.
910 Use of this option is discouraged, as the password is likely to
911 be visible to other users on the system (for example, by using
912 ps(1)).
913 persist
915 Do not exit after a connection is terminated; instead try to
916 reopen the connection. The maxfail option still has an effect on
917 persistent connections.
918 plugin filename
920 Load the shared library object file filename as a plugin. This
921 is a privileged option. If filename does not contain a slash
922 (/), pppd will look in the /usr/lib/pppd/version directory for
923 the plugin, where version is the version number of pppd (for
924 example, 2.4.2).
925 predictor1
927 Request that the peer compress frames that it sends using Pre‐
928 dictor-1 compression, and agree to compress transmitted frames
929 with Predictor-1 if requested. This option has no effect unless
930 the kernel driver supports Predictor-1 compression.
931 privgroup group-name
933 Allows members of group group-name to use privileged options.
934 This is a privileged option. Use of this option requires care
935 as there is no guarantee that members of group-name cannot use
936 pppd to become root themselves. Consider it equivalent to
937 putting the members of group-name in the kmem or disk group.
938 proxyarp
940 Add an entry to this system's ARP [Address Resolution Protocol]
941 table with the IP address of the peer and the Ethernet address
942 of this system. This will have the effect of making the peer
943 appear to other systems to be on the local ethernet.
944 pty script
946 Specifies that the command script is to be used to communicate
947 rather than a specific terminal device. Pppd will allocate
948 itself a pseudo-tty master/slave pair and use the slave as its
949 terminal device. The script will be run in a child process with
950 the pseudo-tty master as its standard input and output. An
951 explicit device name may not be given if this option is used.
952 (Note: if the record option is used in conjunction with the pty
953 option, the child process will have pipes on its standard input
954 and output.)
955 receive-all
957 With this option, pppd will accept all control characters from
958 the peer, including those marked in the receive asyncmap. With‐
959 out this option, pppd will discard those characters as specified
960 in RFC1662. This option should only be needed if the peer is
961 buggy.
962 record filename
964 Specifies that pppd should record all characters sent and
965 received to a file named filename. This file is opened in
966 append mode, using the user's user-ID and permissions. This
967 option is implemented using a pseudo-tty and a process to trans‐
968 fer characters between the pseudo-tty and the real serial
969 device, so it will increase the latency and CPU overhead of
970 transferring data over the ppp interface. The characters are
971 stored in a tagged format with timestamps, which can be dis‐
972 played in readable form using the pppdump(8) program.
973 remotename name
975 Set the assumed name of the remote system for authentication
976 purposes to name.
977 remotenumber number
979 Set the assumed telephone number of the remote system for
980 authentication purposes to number.
981 refuse-chap
983 With this option, pppd will not agree to authenticate itself to
984 the peer using CHAP.
985 refuse-mschap
987 With this option, pppd will not agree to authenticate itself to
988 the peer using MS-CHAP.
989 refuse-mschap-v2
991 With this option, pppd will not agree to authenticate itself to
992 the peer using MS-CHAPv2.
993 refuse-eap
995 With this option, pppd will not agree to authenticate itself to
996 the peer using EAP.
997 refuse-pap
999 With this option, pppd will not agree to authenticate itself to
1000 the peer using PAP.
1001 require-chap
1003 Require the peer to authenticate itself using CHAP [Challenge
1004 Handshake Authentication Protocol] authentication.
1005 require-mppe
1007 Require the use of MPPE (Microsoft Point to Point Encryption).
1008 This option disables all other compression types. This option
1009 enables both 40-bit and 128-bit encryption. In order for MPPE
1010 to successfully come up, you must have authenticated with either
1011 MS-CHAP or MS-CHAPv2. This option is presently only supported
1012 under Linux, and only if your kernel has been configured to
1013 include MPPE support.
1014 require-mppe-40
1016 Require the use of MPPE, with 40-bit encryption.
1017 require-mppe-128
1019 Require the use of MPPE, with 128-bit encryption.
1020 require-mschap
1022 Require the peer to authenticate itself using MS-CHAP [Microsoft
1023 Challenge Handshake Authentication Protocol] authentication.
1024 require-mschap-v2
1026 Require the peer to authenticate itself using MS-CHAPv2 [Micro‐
1027 soft Challenge Handshake Authentication Protocol, Version 2]
1028 authentication.
1029 require-eap
1031 Require the peer to authenticate itself using EAP [Extensible
1032 Authentication Protocol] authentication.
1033 require-pap
1035 Require the peer to authenticate itself using PAP [Password
1036 Authentication Protocol] authentication.
1037 set name=value
1039 Set an environment variable for scripts that are invoked by
1040 pppd. When set by a privileged source, the variable specified
1041 by name cannot be changed by options contained in an unprivi‐
1042 leged source. See also the unset option and the environment
1043 described in SCRIPTS.
1044 show-password
1046 When logging the contents of PAP packets, this option causes
1047 pppd to show the password string in the log message.
1048 silent With this option, pppd will not transmit LCP packets to initiate
1050 a connection until a valid LCP packet is received from the peer
1051 (as for the `passive' option with ancient versions of pppd).
1052 srp-interval n
1054 If this parameter is given and pppd uses EAP SRP-SHA1 to authen‐
1055 ticate the peer (i.e., is the server), then pppd will use the
1056 optional lightweight SRP rechallenge mechanism at intervals of n
1057 seconds. This option is faster than eap-interval reauthentica‐
1058 tion because it uses a hash-based mechanism and does not derive
1059 a new session key.
1060 srp-pn-secret string
1062 Set the long-term pseudonym-generating secret for the server.
1063 This value is optional and if set, needs to be known at the
1064 server (authenticator) side only, and should be different for
1065 each server (or poll of identical servers). It is used along
1066 with the current date to generate a key to encrypt and decrypt
1067 the client's identity contained in the pseudonym.
1068 srp-use-pseudonym
1070 When operating as an EAP SRP-SHA1 client, attempt to use the
1071 pseudonym stored in ~/.ppp_pseudonym first as the identity, and
1072 save in this file any pseudonym offered by the peer during
1073 authentication.
1074 sync Use synchronous HDLC serial encoding instead of asynchronous.
1076 The device used by pppd with this option must have sync support.
1077 Currently supports Microgate SyncLink adapters under Linux and
1078 FreeBSD 2.2.8 and later.
1079 unit num
1081 Sets the ppp unit number (for a ppp0 or ppp1 etc interface name)
1082 for outbound connections.
1083 unset name
1085 Remove a variable from the environment variable for scripts that
1086 are invoked by pppd. When specified by a privileged source, the
1087 variable name cannot be set by options contained in an unprivi‐
1088 leged source. See also the set option and the environment
1089 described in SCRIPTS.
1090 updetach
1092 With this option, pppd will detach from its controlling terminal
1093 once it has successfully established the ppp connection (to the
1094 point where the first network control protocol, usually the IP
1095 control protocol, has come up).
1096 usehostname
1098 Enforce the use of the hostname (with domain name appended, if
1099 given) as the name of the local system for authentication pur‐
1100 poses (overrides the name option). This option is not normally
1101 needed since the name option is privileged.
1102 usepeerdns
1104 Ask the peer for up to 2 DNS server addresses. The addresses
1105 supplied by the peer (if any) are passed to the /etc/ppp/ip-up
1106 script in the environment variables DNS1 and DNS2, and the envi‐
1107 ronment variable USEPEERDNS will be set to 1. In addition, pppd
1108 will create an /var/run/ppp/resolv.conf file containing one or
1109 two nameserver lines with the address(es) supplied by the peer.
1110 user name
1112 Sets the name used for authenticating the local system to the
1113 peer to name.
1114 vj-max-slots n
1116 Sets the number of connection slots to be used by the Van Jacob‐
1117 son TCP/IP header compression and decompression code to n, which
1118 must be between 2 and 16 (inclusive).
1119 welcome script
1121 Run the executable or shell command specified by script before
1122 initiating PPP negotiation, after the connect script (if any)
1123 has completed. A value for this option from a privileged source
1124 cannot be overridden by a non-privileged user.
1125 xonxoff
1127 Use software flow control (i.e. XON/XOFF) to control the flow of
1128 data on the serial port.
1129
1131 Options can be taken from files as well as the command line. Pppd
1132 reads options from the files /etc/ppp/options, ~/.ppprc and
1133 /etc/ppp/options.ttyname (in that order) before processing the options
1134 on the command line. (In fact, the command-line options are scanned to
1135 find the terminal name before the options.ttyname file is read.) In
1136 forming the name of the options.ttyname file, the initial /dev/ is
1137 removed from the terminal name, and any remaining / characters are
1138 replaced with dots.
1139 An options file is parsed into a series of words, delimited by white‐
1141 space. Whitespace can be included in a word by enclosing the word in
1142 double-quotes ("). A backslash (\) quotes the following character. A
1143 hash (#) starts a comment, which continues until the end of the line.
1144 There is no restriction on using the file or call options within an
1145 options file.
1146
1148 pppd provides system administrators with sufficient access control that
1149 PPP access to a server machine can be provided to legitimate users
1150 without fear of compromising the security of the server or the network
1151 it's on. This control is provided through restrictions on which IP
1152 addresses the peer may use, based on its authenticated identity (if
1153 any), and through restrictions on which options a non-privileged user
1154 may use. Several of pppd's options are privileged, in particular those
1155 which permit potentially insecure configurations; these options are
1156 only accepted in files which are under the control of the system admin‐
1157 istrator, or if pppd is being run by root.
1158 The default behaviour of pppd is to allow an unauthenticated peer to
1160 use a given IP address only if the system does not already have a route
1161 to that IP address. For example, a system with a permanent connection
1162 to the wider internet will normally have a default route, and thus all
1163 peers will have to authenticate themselves in order to set up a connec‐
1164 tion. On such a system, the auth option is the default. On the other
1165 hand, a system where the PPP link is the only connection to the inter‐
1166 net will not normally have a default route, so the peer will be able to
1167 use almost any IP address without authenticating itself.
1168 As indicated above, some security-sensitive options are privileged,
1170 which means that they may not be used by an ordinary non-privileged
1171 user running a setuid-root pppd, either on the command line, in the
1172 user's ~/.ppprc file, or in an options file read using the file option.
1173 Privileged options may be used in /etc/ppp/options file or in an
1174 options file read using the call option. If pppd is being run by the
1175 root user, privileged options can be used without restriction.
1176 When opening the device, pppd uses either the invoking user's user ID
1178 or the root UID (that is, 0), depending on whether the device name was
1179 specified by the user or the system administrator. If the device name
1180 comes from a privileged source, that is, /etc/ppp/options or an options
1181 file read using the call option, pppd uses full root privileges when
1182 opening the device. Thus, by creating an appropriate file under
1183 /etc/ppp/peers, the system administrator can allow users to establish a
1184 ppp connection via a device which they would not normally have permis‐
1185 sion to access. Otherwise pppd uses the invoking user's real UID when
1186 opening the device.
1187
1189 Authentication is the process whereby one peer convinces the other of
1190 its identity. This involves the first peer sending its name to the
1191 other, together with some kind of secret information which could only
1192 come from the genuine authorized user of that name. In such an
1193 exchange, we will call the first peer the "client" and the other the
1194 "server". The client has a name by which it identifies itself to the
1195 server, and the server also has a name by which it identifies itself to
1196 the client. Generally the genuine client shares some secret (or pass‐
1197 word) with the server, and authenticates itself by proving that it
1198 knows that secret. Very often, the names used for authentication cor‐
1199 respond to the internet hostnames of the peers, but this is not essen‐
1200 tial.
1201 At present, pppd supports three authentication protocols: the Password
1203 Authentication Protocol (PAP), Challenge Handshake Authentication Pro‐
1204 tocol (CHAP), and Extensible Authentication Protocol (EAP). PAP
1205 involves the client sending its name and a cleartext password to the
1206 server to authenticate itself. In contrast, the server initiates the
1207 CHAP authentication exchange by sending a challenge to the client (the
1208 challenge packet includes the server's name). The client must respond
1209 with a response which includes its name plus a hash value derived from
1210 the shared secret and the challenge, in order to prove that it knows
1211 the secret. EAP supports CHAP-style authentication, and also includes
1212 the SRP-SHA1 mechanism, which is resistant to dictionary-based attacks
1213 and does not require a cleartext password on the server side.
1214 The PPP protocol, being symmetrical, allows both peers to require the
1216 other to authenticate itself. In that case, two separate and indepen‐
1217 dent authentication exchanges will occur. The two exchanges could use
1218 different authentication protocols, and in principle, different names
1219 could be used in the two exchanges.
1220 The default behaviour of pppd is to agree to authenticate if requested,
1222 and to not require authentication from the peer. However, pppd will
1223 not agree to authenticate itself with a particular protocol if it has
1224 no secrets which could be used to do so.
1225 Pppd stores secrets for use in authentication in secrets files
1227 (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP, MS-CHAP,
1228 MS-CHAPv2, and EAP MD5-Challenge, and /etc/ppp/srp-secrets for EAP
1229 SRP-SHA1). All secrets files have the same format. The secrets files
1230 can contain secrets for pppd to use in authenticating itself to other
1231 systems, as well as secrets for pppd to use when authenticating other
1232 systems to itself.
1233 Each line in a secrets file contains one secret. A given secret is
1235 specific to a particular combination of client and server - it can only
1236 be used by that client to authenticate itself to that server. Thus
1237 each line in a secrets file has at least 3 fields: the name of the
1238 client, the name of the server, and the secret. These fields may be
1239 followed by a list of the IP addresses that the specified client may
1240 use when connecting to the specified server.
1241 A secrets file is parsed into words as for a options file, so the
1243 client name, server name and secrets fields must each be one word, with
1244 any embedded spaces or other special characters quoted or escaped.
1245 Note that case is significant in the client and server names and in the
1246 secret.
1247 If the secret starts with an `@', what follows is assumed to be the
1249 name of a file from which to read the secret. A "*" as the client or
1250 server name matches any name. When selecting a secret, pppd takes the
1251 best match, i.e. the match with the fewest wildcards.
1252 Any following words on the same line are taken to be a list of accept‐
1254 able IP addresses for that client. If there are only 3 words on the
1255 line, or if the first word is "-", then all IP addresses are disal‐
1256 lowed. To allow any address, use "*". A word starting with "!" indi‐
1257 cates that the specified address is not acceptable. An address may be
1258 followed by "/" and a number n, to indicate a whole subnet, i.e. all
1259 addresses which have the same value in the most significant n bits. In
1260 this form, the address may be followed by a plus sign ("+") to indicate
1261 that one address from the subnet is authorized, based on the ppp net‐
1262 work interface unit number in use. In this case, the host part of the
1263 address will be set to the unit number plus one.
1264 Thus a secrets file contains both secrets for use in authenticating
1266 other hosts, plus secrets which we use for authenticating ourselves to
1267 others. When pppd is authenticating the peer (checking the peer's
1268 identity), it chooses a secret with the peer's name in the first field
1269 and the name of the local system in the second field. The name of the
1270 local system defaults to the hostname, with the domain name appended if
1271 the domain option is used. This default can be overridden with the
1272 name option, except when the usehostname option is used. (For EAP
1273 SRP-SHA1, see the srp-entry(8) utility for generating proper validator
1274 entries to be used in the "secret" field.)
1275 When pppd is choosing a secret to use in authenticating itself to the
1277 peer, it first determines what name it is going to use to identify
1278 itself to the peer. This name can be specified by the user with the
1279 user option. If this option is not used, the name defaults to the name
1280 of the local system, determined as described in the previous paragraph.
1281 Then pppd looks for a secret with this name in the first field and the
1282 peer's name in the second field. Pppd will know the name of the peer
1283 if CHAP or EAP authentication is being used, because the peer will have
1284 sent it in the challenge packet. However, if PAP is being used, pppd
1285 will have to determine the peer's name from the options specified by
1286 the user. The user can specify the peer's name directly with the
1287 remotename option. Otherwise, if the remote IP address was specified
1288 by a name (rather than in numeric form), that name will be used as the
1289 peer's name. Failing that, pppd will use the null string as the peer's
1290 name.
1291 When authenticating the peer with PAP, the supplied password is first
1293 compared with the secret from the secrets file. If the password
1294 doesn't match the secret, the password is encrypted using crypt() and
1295 checked against the secret again. Thus secrets for authenticating the
1296 peer can be stored in encrypted form if desired. If the papcrypt
1297 option is given, the first (unencrypted) comparison is omitted, for
1298 better security.
1299 Furthermore, if the login option was specified, the username and pass‐
1301 word are also checked against the system password database. Thus, the
1302 system administrator can set up the pap-secrets file to allow PPP
1303 access only to certain users, and to restrict the set of IP addresses
1304 that each user can use. Typically, when using the login option, the
1305 secret in /etc/ppp/pap-secrets would be "", which will match any pass‐
1306 word supplied by the peer. This avoids the need to have the same
1307 secret in two places.
1308 Authentication must be satisfactorily completed before IPCP (or any
1310 other Network Control Protocol) can be started. If the peer is
1311 required to authenticate itself, and fails to do so, pppd will termi‐
1312 nated the link (by closing LCP). If IPCP negotiates an unacceptable IP
1313 address for the remote host, IPCP will be closed. IP packets can only
1314 be sent or received when IPCP is open.
1315 In some cases it is desirable to allow some hosts which can't authenti‐
1317 cate themselves to connect and use one of a restricted set of IP
1318 addresses, even when the local host generally requires authentication.
1319 If the peer refuses to authenticate itself when requested, pppd takes
1320 that as equivalent to authenticating with PAP using the empty string
1321 for the username and password. Thus, by adding a line to the
1322 pap-secrets file which specifies the empty string for the client and
1323 password, it is possible to allow restricted access to hosts which
1324 refuse to authenticate themselves.
1325
1327 When IPCP negotiation is completed successfully, pppd will inform the
1328 kernel of the local and remote IP addresses for the ppp interface.
1329 This is sufficient to create a host route to the remote end of the
1330 link, which will enable the peers to exchange IP packets. Communica‐
1331 tion with other machines generally requires further modification to
1332 routing tables and/or ARP (Address Resolution Protocol) tables. In
1333 most cases the defaultroute and/or proxyarp options are sufficient for
1334 this, but in some cases further intervention is required. The
1335 /etc/ppp/ip-up script can be used for this.
1336 Sometimes it is desirable to add a default route through the remote
1338 host, as in the case of a machine whose only connection to the Internet
1339 is through the ppp interface. The defaultroute option causes pppd to
1340 create such a default route when IPCP comes up, and delete it when the
1341 link is terminated.
1342 In some cases it is desirable to use proxy ARP, for example on a server
1344 machine connected to a LAN, in order to allow other hosts to communi‐
1345 cate with the remote host. The proxyarp option causes pppd to look for
1346 a network interface on the same subnet as the remote host (an interface
1347 supporting broadcast and ARP, which is up and not a point-to-point or
1348 loopback interface). If found, pppd creates a permanent, published ARP
1349 entry with the IP address of the remote host and the hardware address
1350 of the network interface found.
1351 When the demand option is used, the interface IP addresses have already
1353 been set at the point when IPCP comes up. If pppd has not been able to
1354 negotiate the same addresses that it used to configure the interface
1355 (for example when the peer is an ISP that uses dynamic IP address
1356 assignment), pppd has to change the interface IP addresses to the nego‐
1357 tiated addresses. This may disrupt existing connections, and the use
1358 of demand dialling with peers that do dynamic IP address assignment is
1359 not recommended.
1360
1362 Multilink PPP provides the capability to combine two or more PPP links
1363 between a pair of machines into a single `bundle', which appears as a
1364 single virtual PPP link which has the combined bandwidth of the indi‐
1365 vidual links. Currently, multilink PPP is only supported under Linux.
1366 Pppd detects that the link it is controlling is connected to the same
1368 peer as another link using the peer's endpoint discriminator and the
1369 authenticated identity of the peer (if it authenticates itself). The
1370 endpoint discriminator is a block of data which is hopefully unique for
1371 each peer. Several types of data can be used, including locally-
1372 assigned strings of bytes, IP addresses, MAC addresses, randomly
1373 strings of bytes, or E-164 phone numbers. The endpoint discriminator
1374 sent to the peer by pppd can be set using the endpoint option.
1375 In some circumstances the peer may send no endpoint discriminator or a
1377 non-unique value. The bundle option adds an extra string which is
1378 added to the peer's endpoint discriminator and authenticated identity
1379 when matching up links to be joined together in a bundle. The bundle
1380 option can also be used to allow the establishment of multiple bundles
1381 between the local system and the peer. Pppd uses a TDB database in
1382 /var/run/pppd2.tdb to match up links.
1383 Assuming that multilink is enabled and the peer is willing to negotiate
1385 multilink, then when pppd is invoked to bring up the first link to the
1386 peer, it will detect that no other link is connected to the peer and
1387 create a new bundle, that is, another ppp network interface unit. When
1388 another pppd is invoked to bring up another link to the peer, it will
1389 detect the existing bundle and join its link to it.
1390 If the first link terminates (for example, because of a hangup or a
1392 received LCP terminate-request) the bundle is not destroyed unless
1393 there are no other links remaining in the bundle. Rather than exiting,
1394 the first pppd keeps running after its link terminates, until all the
1395 links in the bundle have terminated. If the first pppd receives a
1396 SIGTERM or SIGINT signal, it will destroy the bundle and send a SIGHUP
1397 to the pppd processes for each of the links in the bundle. If the
1398 first pppd receives a SIGHUP signal, it will terminate its link but not
1399 the bundle.
1400 Note: demand mode is not currently supported with multilink.
1402
1404 The following examples assume that the /etc/ppp/options file contains
1405 the auth option (as in the default /etc/ppp/options file in the ppp
1406 distribution).
1407 Probably the most common use of pppd is to dial out to an ISP. This
1409 can be done with a command such as
1410 pppd call isp
1412 where the /etc/ppp/peers/isp file is set up by the system administrator
1414 to contain something like this:
1415 ttyS0 19200 crtscts
1417 connect '/usr/sbin/chat -v -f /etc/ppp/chat-isp'
1418 noauth
1419 In this example, we are using chat to dial the ISP's modem and go
1421 through any logon sequence required. The /etc/ppp/chat-isp file con‐
1422 tains the script used by chat; it could for example contain something
1423 like this:
1424 ABORT "NO CARRIER"
1426 ABORT "NO DIALTONE"
1427 ABORT "ERROR"
1428 ABORT "NO ANSWER"
1429 ABORT "BUSY"
1430 ABORT "Username/Password Incorrect"
1431 "" "at"
1432 OK "at&d0&c1"
1433 OK "atdt2468135"
1434 "name:" "^Umyuserid"
1435 "word:" "\qmypassword"
1436 "ispts" "\q^Uppp"
1437 "~-^Uppp-~"
1438 See the chat(8) man page for details of chat scripts.
1440 Pppd can also be used to provide a dial-in ppp service for users. If
1442 the users already have login accounts, the simplest way to set up the
1443 ppp service is to let the users log in to their accounts and run pppd
1444 (installed setuid-root) with a command such as
1445 pppd proxyarp
1447 To allow a user to use the PPP facilities, you need to allocate an IP
1449 address for that user's machine and create an entry in
1450 /etc/ppp/pap-secrets, /etc/ppp/chap-secrets, or /etc/ppp/srp-secrets
1451 (depending on which authentication method the PPP implementation on the
1452 user's machine supports), so that the user's machine can authenticate
1453 itself. For example, if Joe has a machine called "joespc" that is to
1454 be allowed to dial in to the machine called "server" and use the IP
1455 address joespc.my.net, you would add an entry like this to
1456 /etc/ppp/pap-secrets or /etc/ppp/chap-secrets:
1457 joespc server "joe's secret" joespc.my.net
1459 (See srp-entry(8) for a means to generate the server's entry when
1461 SRP-SHA1 is in use.) Alternatively, you can create a username called
1462 (for example) "ppp", whose login shell is pppd and whose home directory
1463 is /etc/ppp. Options to be used when pppd is run this way can be put
1464 in /etc/ppp/.ppprc.
1465 If your serial connection is any more complicated than a piece of wire,
1467 you may need to arrange for some control characters to be escaped. In
1468 particular, it is often useful to escape XON (^Q) and XOFF (^S), using
1469 asyncmap a0000. If the path includes a telnet, you probably should
1470 escape ^] as well (asyncmap 200a0000). If the path includes an rlogin,
1471 you will need to use the escape ff option on the end which is running
1472 the rlogin client, since many rlogin implementations are not transpar‐
1473 ent; they will remove the sequence [0xff, 0xff, 0x73, 0x73, followed by
1474 any 8 bytes] from the stream.
1475
1477 Messages are sent to the syslog daemon using facility LOG_DAEMON.
1478 (This can be overridden by recompiling pppd with the macro LOG_PPP
1479 defined as the desired facility.) See the syslog(8) documentation for
1480 details of where the syslog daemon will write the messages. On most
1481 systems, the syslog daemon uses the /etc/syslog.conf file to specify
1482 the destination(s) for syslog messages. You may need to edit that file
1483 to suit.
1484 The debug option causes the contents of all control packets sent or
1486 received to be logged, that is, all LCP, PAP, CHAP, EAP, or IPCP pack‐
1487 ets. This can be useful if the PPP negotiation does not succeed or if
1488 authentication fails. If debugging is enabled at compile time, the
1489 debug option also causes other debugging messages to be logged.
1490 Debugging can also be enabled or disabled by sending a SIGUSR1 signal
1492 to the pppd process. This signal acts as a toggle.
1493
1495 The exit status of pppd is set to indicate whether any error was
1496 detected, or the reason for the link being terminated. The values used
1497 are:
1498 0 Pppd has detached, or otherwise the connection was successfully
1500 established and terminated at the peer's request.
1501 1 An immediately fatal error of some kind occurred, such as an
1503 essential system call failing, or running out of virtual memory.
1504 2 An error was detected in processing the options given, such as
1506 two mutually exclusive options being used.
1507 3 Pppd is not setuid-root and the invoking user is not root.
1509 4 The kernel does not support PPP, for example, the PPP kernel
1511 driver is not included or cannot be loaded.
1512 5 Pppd terminated because it was sent a SIGINT, SIGTERM or SIGHUP
1514 signal.
1515 6 The serial port could not be locked.
1517 7 The serial port could not be opened.
1519 8 The connect script failed (returned a non-zero exit status).
1521 9 The command specified as the argument to the pty option could
1523 not be run.
1524 10 The PPP negotiation failed, that is, it didn't reach the point
1526 where at least one network protocol (e.g. IP) was running.
1527 11 The peer system failed (or refused) to authenticate itself.
1529 12 The link was established successfully and terminated because it
1531 was idle.
1532 13 The link was established successfully and terminated because the
1534 connect time limit was reached.
1535 14 Callback was negotiated and an incoming call should arrive
1537 shortly.
1538 15 The link was terminated because the peer is not responding to
1540 echo requests.
1541 16 The link was terminated by the modem hanging up.
1543 17 The PPP negotiation failed because serial loopback was detected.
1545 18 The init script failed (returned a non-zero exit status).
1547 19 We failed to authenticate ourselves to the peer.
1549
1551 Pppd invokes scripts at various stages in its processing which can be
1552 used to perform site-specific ancillary processing. These scripts are
1553 usually shell scripts, but could be executable code files instead.
1554 Pppd does not wait for the scripts to finish (except for the ip-pre-up
1555 script). The scripts are executed as root (with the real and effective
1556 user-id set to 0), so that they can do things such as update routing
1557 tables or run privileged daemons. Be careful that the contents of
1558 these scripts do not compromise your system's security. Pppd runs the
1559 scripts with standard input, output and error redirected to /dev/null,
1560 and with an environment that is empty except for some environment vari‐
1561 ables that give information about the link. The environment variables
1562 that pppd sets are:
1563 DEVICE The name of the serial tty device being used.
1565 IFNAME The name of the network interface being used.
1567 IPLOCAL
1569 The IP address for the local end of the link. This is only set
1570 when IPCP has come up.
1571 IPREMOTE
1573 The IP address for the remote end of the link. This is only set
1574 when IPCP has come up.
1575 PEERNAME
1577 The authenticated name of the peer. This is only set if the
1578 peer authenticates itself.
1579 SPEED The baud rate of the tty device.
1581 ORIG_UID
1583 The real user-id of the user who invoked pppd.
1584 PPPLOGNAME
1586 The username of the real user-id that invoked pppd. This is
1587 always set.
1588 For the ip-down and auth-down scripts, pppd also sets the following
1590 variables giving statistics for the connection:
1591 CONNECT_TIME
1593 The number of seconds from when the PPP negotiation started
1594 until the connection was terminated.
1595 BYTES_SENT
1597 The number of bytes sent (at the level of the serial port) dur‐
1598 ing the connection.
1599 BYTES_RCVD
1601 The number of bytes received (at the level of the serial port)
1602 during the connection.
1603 LINKNAME
1605 The logical name of the link, set with the linkname option.
1606 DNS1 If the peer supplies DNS server addresses, this variable is set
1608 to the first DNS server address supplied (whether or not the
1609 usepeerdns option was given).
1610 DNS2 If the peer supplies DNS server addresses, this variable is set
1612 to the second DNS server address supplied (whether or not the
1613 usepeerdns option was given).
1614 Pppd invokes the following scripts, if they exist. It is not an error
1616 if they don't exist.
1617 /etc/ppp/auth-up
1619 A program or script which is executed after the remote system
1620 successfully authenticates itself. It is executed with the
1621 parameters
1622 interface-name peer-name user-name tty-device speed
1624 Note that this script is not executed if the peer doesn't
1626 authenticate itself, for example when the noauth option is used.
1627 /etc/ppp/auth-down
1629 A program or script which is executed when the link goes down,
1630 if /etc/ppp/auth-up was previously executed. It is executed in
1631 the same manner with the same parameters as /etc/ppp/auth-up.
1632 /etc/ppp/ip-pre-up
1634 A program or script which is executed just before the ppp net‐
1635 work interface is brought up. It is executed with the same
1636 parameters as the ip-up script (below). At this point the
1637 interface exists and has IP addresses assigned but is still
1638 down. This can be used to add firewall rules before any IP
1639 traffic can pass through the interface. Pppd will wait for this
1640 script to finish before bringing the interface up, so this
1641 script should run quickly.
1642 /etc/ppp/ip-up
1644 A program or script which is executed when the link is available
1645 for sending and receiving IP packets (that is, IPCP has come
1646 up). It is executed with the parameters
1647 interface-name tty-device speed local-IP-address
1649 remote-IP-address ipparam
1650 /etc/ppp/ip-down
1652 A program or script which is executed when the link is no longer
1653 available for sending and receiving IP packets. This script can
1654 be used for undoing the effects of the /etc/ppp/ip-up and
1655 /etc/ppp/ip-pre-up scripts. It is invoked in the same manner
1656 and with the same parameters as the ip-up script.
1657 /etc/ppp/ipv6-up
1659 Like /etc/ppp/ip-up, except that it is executed when the link is
1660 available for sending and receiving IPv6 packets. It is executed
1661 with the parameters
1662 interface-name tty-device speed local-link-local-address
1664 remote-link-local-address ipparam
1665 /etc/ppp/ipv6-down
1667 Similar to /etc/ppp/ip-down, but it is executed when IPv6 pack‐
1668 ets can no longer be transmitted on the link. It is executed
1669 with the same parameters as the ipv6-up script.
1670 /etc/ppp/ipx-up
1672 A program or script which is executed when the link is available
1673 for sending and receiving IPX packets (that is, IPXCP has come
1674 up). It is executed with the parameters
1675 interface-name tty-device speed network-number
1677 local-IPX-node-address remote-IPX-node-address local-IPX-rout‐
1678 ing-protocol remote-IPX-routing-protocol local-IPX-router-name
1679 remote-IPX-router-name ipparam pppd-pid
1680 The local-IPX-routing-protocol and remote-IPX-routing-protocol
1682 field may be one of the following:
1683 NONE to indicate that there is no routing protocol
1685 RIP to indicate that RIP/SAP should be used
1686 NLSP to indicate that Novell NLSP should be used
1687 RIP NLSP to indicate that both RIP/SAP and NLSP should be used
1688 /etc/ppp/ipx-down
1690 A program or script which is executed when the link is no longer
1691 available for sending and receiving IPX packets. This script
1692 can be used for undoing the effects of the /etc/ppp/ipx-up
1693 script. It is invoked in the same manner and with the same
1694 parameters as the ipx-up script.
1695
1697 /var/run/pppn.pid (BSD or Linux), /etc/ppp/pppn.pid (others)
1698 Process-ID for pppd process on ppp interface unit n.
1699 /var/run/ppp-name.pid (BSD or Linux),
1701 /etc/ppp/ppp-name.pid (others) Process-ID for pppd process for
1702 logical link name (see the linkname option).
1703 /var/run/pppd2.tdb
1705 Database containing information about pppd processes, interfaces
1706 and links, used for matching links to bundles in multilink oper‐
1707 ation. May be examined by external programs to obtain informa‐
1708 tion about running pppd instances, the interfaces and devices
1709 they are using, IP address assignments, etc.
1710 /etc/ppp/pap-secrets Usernames, passwords and IP addresses for
1711 PAP authentication. This file should be owned by root and not
1712 readable or writable by any other user. Pppd will log a warning
1713 if this is not the case.
1714 /etc/ppp/chap-secrets
1716 Names, secrets and IP addresses for CHAP/MS-CHAP/MS-CHAPv2
1717 authentication. As for /etc/ppp/pap-secrets, this file should
1718 be owned by root and not readable or writable by any other user.
1719 Pppd will log a warning if this is not the case.
1720 /etc/ppp/srp-secrets
1722 Names, secrets, and IP addresses for EAP authentication. As for
1723 /etc/ppp/pap-secrets, this file should be owned by root and not
1724 readable or writable by any other user. Pppd will log a warning
1725 if this is not the case.
1726 ~/.ppp_pseudonym
1728 Saved client-side SRP-SHA1 pseudonym. See the srp-use-pseudonym
1729 option for details.
1730 /etc/ppp/options
1732 System default options for pppd, read before user default
1733 options or command-line options.
1734 ~/.ppprc
1736 User default options, read before /etc/ppp/options.ttyname.
1737 /etc/ppp/options.ttyname
1739 System default options for the serial port being used, read
1740 after ~/.ppprc. In forming the ttyname part of this filename,
1741 an initial /dev/ is stripped from the port name (if present),
1742 and any slashes in the remaining part are converted to dots.
1743 /etc/ppp/peers
1745 A directory containing options files which may contain privi‐
1746 leged options, even if pppd was invoked by a user other than
1747 root. The system administrator can create options files in this
1748 directory to permit non-privileged users to dial out without
1749 requiring the peer to authenticate, but only to certain trusted
1750 peers.
1751
1753 chat(8), pppstats(8)
1754 RFC1144
1756 Jacobson, V. Compressing TCP/IP headers for low-speed serial
1757 links. February 1990.
1758 RFC1321
1760 Rivest, R. The MD5 Message-Digest Algorithm. April 1992.
1761 RFC1332
1763 McGregor, G. PPP Internet Protocol Control Protocol (IPCP).
1764 May 1992.
1765 RFC1334
1767 Lloyd, B.; Simpson, W.A. PPP authentication protocols. October
1768 1992.
1769 RFC1661
1771 Simpson, W.A. The Point-to-Point Protocol (PPP). July 1994.
1772 RFC1662
1774 Simpson, W.A. PPP in HDLC-like Framing. July 1994.
1775 RFC2284
1777 Blunk, L.; Vollbrecht, J., PPP Extensible Authentication Proto‐
1778 col (EAP). March 1998.
1779 RFC2472
1781 Haskin, D. IP Version 6 over PPP December 1998.
1782 RFC2945
1784 Wu, T., The SRP Authentication and Key Exchange System September
1785 2000.
1786 draft-ietf-pppext-eap-srp-03.txt
1788 Carlson, J.; et al., EAP SRP-SHA1 Authentication Protocol. July
1789 2001.
1790
1792 Some limited degree of control can be exercised over a running pppd
1793 process by sending it a signal from the list below.
1794 SIGINT, SIGTERM
1796 These signals cause pppd to terminate the link (by closing LCP),
1797 restore the serial device settings, and exit. If a connector or
1798 disconnector process is currently running, pppd will send the
1799 same signal to its process group, so as to terminate the connec‐
1800 tor or disconnector process.
1801 SIGHUP This signal causes pppd to terminate the link, restore the
1803 serial device settings, and close the serial device. If the
1804 persist or demand option has been specified, pppd will try to
1805 reopen the serial device and start another connection (after the
1806 holdoff period). Otherwise pppd will exit. If this signal is
1807 received during the holdoff period, it causes pppd to end the
1808 holdoff period immediately. If a connector or disconnector
1809 process is running, pppd will send the same signal to its
1810 process group.
1811 SIGUSR1
1813 This signal toggles the state of the debug option.
1814 SIGUSR2
1816 This signal causes pppd to renegotiate compression. This can be
1817 useful to re-enable compression after it has been disabled as a
1818 result of a fatal decompression error. (Fatal decompression
1819 errors generally indicate a bug in one or other implementation.)
1820
1823 Paul Mackerras (paulus@samba.org), based on earlier work by Drew
1824 Perkins, Brad Clements, Karl Fox, Greg Christy, and Brad Parker.
1825
1828 Pppd is copyrighted and made available under conditions which provide
1829 that it may be copied and used in source or binary forms provided that
1830 the conditions listed below are met. Portions of pppd are covered by
1831 the following copyright notices:
1832 Copyright (c) 1984-2000 Carnegie Mellon University. All rights
1834 reserved.
1835 Copyright (c) 1993-2004 Paul Mackerras. All rights reserved.
1836 Copyright (c) 1995 Pedro Roque Marques. All rights reserved.
1837 Copyright (c) 1995 Eric Rosenquist. All rights reserved.
1838 Copyright (c) 1999 Tommi Komulainen. All rights reserved.
1839 Copyright (C) Andrew Tridgell 1999
1840 Copyright (c) 2000 by Sun Microsystems, Inc. All rights reserved.
1841 Copyright (c) 2001 by Sun Microsystems, Inc. All rights reserved.
1842 Copyright (c) 2002 Google, Inc. All rights reserved.
1843 The copyright notices contain the following statements.
1845 Redistribution and use in source and binary forms, with or without mod‐
1847 ification, are permitted provided that the following conditions are
1848 met:
1849 1. Redistributions of source code must retain the above copyright
1851 notice, this list of conditions and the following disclaimer.
1852 2. Redistributions in binary form must reproduce the above copyright
1854 notice, this list of conditions and the following disclaimer in
1855 the documentation and/or other materials provided with the
1856 distribution.
1857 3. The name "Carnegie Mellon University" must not be used to
1859 endorse or promote products derived from this software without
1860 prior written permission. For permission or any legal
1861 details, please contact
1862 Office of Technology Transfer
1863 Carnegie Mellon University
1864 5000 Forbes Avenue
1865 Pittsburgh, PA 15213-3890
1866 (412) 268-4387, fax: (412) 268-7395
1867 tech-transfer@andrew.cmu.edu
1868 3b. The name(s) of the authors of this software must not be used to
1870 endorse or promote products derived from this software without
1871 prior written permission.
1872 4. Redistributions of any form whatsoever must retain the following
1874 acknowledgements:
1875 "This product includes software developed by Computing Services
1876 at Carnegie Mellon University (http://www.cmu.edu/computing/)."
1877 "This product includes software developed by Paul Mackerras
1878 <paulus@samba.org>".
1879 "This product includes software developed by Pedro Roque Marques
1880 <pedro_m@yahoo.com>".
1881 "This product includes software developed by Tommi Komulainen
1882 <Tommi.Komulainen@iki.fi>".
1883 CARNEGIE MELLON UNIVERSITY DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
1885 SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FIT‐
1886 NESS, IN NO EVENT SHALL CARNEGIE MELLON UNIVERSITY BE LIABLE FOR ANY
1887 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
1888 RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF
1889 CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
1890 CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
1891 THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
1893 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
1894 FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDI‐
1895 RECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
1896 LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLI‐
1897 GENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH
1898 THE USE OR PERFORMANCE OF THIS SOFTWARE.
1899 PPPD(8)