1IPPPD(8) Linux System Administration IPPPD(8)
2
6 ipppd - (ISDN) Point to Point Protocol daemon
7
9 /usr/sbin/ipppd [ options ] [ device ]
10
12 The Point-to-Point Protocol (PPP) provides a method for transmitting
13 datagrams over serial point-to-point links. PPP is composed of three
14 parts: a method for encapsulating datagrams over serial links, an
15 extensible Link Control Protocol (LCP), and a family of Network Control
16 Protocols (NCP) for establishing and configuring different network-
17 layer protocols.
18 The encapsulation scheme is provided by driver code in the kernel.
20 ipppd provides the basic LCP, authentication support, and an NCP for
21 establishing and configuring the Internet Protocol (IP) (called the IP
22 Control Protocol, IPCP).
23
25 This special (ISDN) PPP daemon is a modified version of pppd and pro‐
26 vides synchronous PPP for ISDN connections.
27 If you need asynchronous PPP over ISDN lines use pppd instead with the
29 ISDN character devices, see ttyI(4).
30 The ipppd can handle multiple devices. This is necessary to link sev‐
32 eral connections together to one bundle. ipppd should be started once.
33 It opens the devices and waits for connections. If the connections is
34 closed ipppd reopens the device automatically (the device, that's it
35 ... not the link to the remote). So you shouldn't kill the ipppd to
36 close a link. Instead, trigger a hangup on the netdevice layer by
37 'isdnctrl hangup <device>'.
38 The facility to configure the daemon via file /etc/ppp/ioptions.<dev‐
40 name> is disabled. The 'file' option or the command line may be used
41 for individual configuration.
42 Do not set the permissions of the program to 'setuid to root on execu‐
44 tion'. Call the daemon as root instead. No common user should have the
45 need to call the daemon!
46
48 <device>
49 Communicate over the named device. The string "/dev/" is
50 prepended if necessary. If no device name is given, or if the
51 name of the controlling terminal is given, ipppd will use the
52 controlling terminal, and will not fork to put itself in the
53 background.
54 <local_IP_address>:<remote_IP_address>
56 Set the local and/or remote interface IP addresses. Either one
57 may be omitted. The IP addresses can be specified with a host
58 name or in decimal dot notation (e.g. 150.234.56.78). The
59 default local address is the (first) IP address of the system
60 (unless the noipdefault option is given). The remote address
61 will be obtained from the peer if not specified in any option.
62 Thus, in simple cases, this option is not required. If a local
63 and/or remote IP address is specified with this option, ipppd
64 will not accept a different value from the peer in the IPCP
65 negotiation, unless the ipcp-accept-local and/or ipcp-accept-
66 remote options are given, respectively.
67 active-filter filter-expression
69 Specifies a packet filter to be applied to data packets to
70 determine which packets are to be regarded as link activity, and
71 therefore reset the idle timer, or cause the link to be brought
72 up in demand-dialling mode. This option is useful in conjunction
73 with the idle option if there are packets being sent or received
74 regularly over the link (for example, routing information pack‐
75 ets) which would otherwise prevent the link from ever appearing
76 to be idle. The filter-expression syntax is as described for
77 tcpdump(1), except that qualifiers which are inappropriate for a
78 PPP link, such as ether and arp, are not permitted. Generally
79 the filter expression should be enclosed in single-quotes to
80 prevent whitespace in the expression from being interpreted by
81 the shell. This option is currently only available if both the
82 kernel and ipppd were compiled with IPPP_FILTER defined.
83 -ac Disable Address/Control compression negotiation (use default,
85 i.e. address/control field compression disabled).
86 -all Don't request or allow negotiation of any options for LCP and
88 IPCP (use default values).
89 auth Require the peer to authenticate itself before allowing network
91 packets to be sent or received.
92 bsdcomp nr,nt
94 Request that the peer compress packets that it sends, using the
95 BSD-Compress scheme, with a maximum code size of nr bits, and
96 agree to compress packets sent to the peer with a maximum code
97 size of nt bits. If nt is not specified, it defaults to the
98 value given for nr. Values in the range 9 to 15 may be used for
99 nr and nt; larger values give better compression but consume
100 more kernel memory for compression dictionaries. Alternatively,
101 a value of 0 for nr or nt disables compression in the corre‐
102 sponding direction.
103 -bsdcomp
105 Disables compression; ipppd will not request or agree to com‐
106 press packets using the BSD-Compress scheme.
107 callback <string>
109 Request the peer to call back at the location given in <string>.
110 Ususally this is a phone number, but it may be interpreted dif‐
111 ferently (or ignored) depending on the callback-type option. If
112 <string> is the empty string, ipppd automatically tries to nego‐
113 tiate a callback type that does not need a location to be speci‐
114 fied.
115 callback-delay <n>
117 Callback delay for CBCP in seconds. If callback is negotiated
118 using CBCP, request that the peer waits at least <n> seconds
119 before calling back. Ignored if callback is negotiated as speci‐
120 fied in RFC 1570. Legal range is 0..255, default is 5.
121 callback-cbcp
123 Enable callback negotiation via CBCB (default).
124 -callback-cbcp
126 Disable callback negotiation via CBCB.
127 no-callback-cbcp
129 Disable callback negotiation via CBCB.
130 callback-cbcp-preferred
132 If both CBCP and RFC 1570 style callback negotiation is enabled,
133 CBCP is preferred (default)
134 callback-rfc1570-preferred
136 If both CBCP and RFC 1570 style callback negotiation is enabled,
137 RFC 1570 style is preferred.
138 callback-rfc1570
140 Enable RFC 1570 style callback negotiation (default).
141 -callback-rfc1570
143 Disable RFC 1570 style callback negotiation.
144 no-callback-rfc1570
146 Disable RFC 1570 style callback negotiation (default).
147 callback-type <n>
149 Specifies how to interpret the location identifier given as
150 parameter of the callback option. Legal values are 0..4. A value
151 of 0 means that only callback types should be negotiated that
152 need no extra location id. No location id is sent to the peer in
153 this case. For RFC 1570 style callback negotiation, the values
154 1..4 indicate how the peer should interpret the location identi‐
155 fier: 1 - id is a system specific dial string, 2 - id is used
156 for database lookup by the peer, 3 - id is a phone number, and 4
157 id is a name. For CBCP callback negotiation, the location id is
158 always interpreted as a phone number.
159 -ccp Necessary for a few netblazers on the remote side.
161 noccp same as -ccp
163 +chap Require the peer to authenticate itself using CHAP [Crypto‐
165 graphic Handshake Authentication Protocol] authentication.
166 -chap Don't agree to authenticate using CHAP.
168 chap-interval <n>
170 If this option is given, ipppd will rechallenge the peer every
171 <n> seconds.
172 chap-max-challenge <n>
174 Set the maximum number of CHAP challenge transmissions to <n>
175 (default 10).
176 chap-restart <n>
178 Set the CHAP restart interval (retransmission timeout for chal‐
179 lenges) to <n> seconds (default 3).
180 debug Increase debugging level (same as -d). If this option is given,
182 ipppd will log the contents of all control packets sent or
183 received in a readable form. The packets are logged through
184 syslog with facility daemon and level debug. This information
185 can be directed to a file by setting up /etc/syslog.conf appro‐
186 priately (see syslog.conf(5)).
187 -d Increase debugging level (same as the debug option).
189 defaultroute
191 Add a default route to the system routing tables, using the peer
192 as the gateway, when IPCP negotiation is successfully completed.
193 This entry is removed when the PPP connection is broken.
194 -defaultroute
196 Disable the defaultroute option. The system administrator who
197 wishes to prevent users from creating default routes with ipppd
198 can do so by placing this option in the /etc/ppp/ioptions file.
199 deldefaultroute
201 Replace default route if it already exists. Together with the
202 option defaultroute, this will replace any existing default
203 route by a new one through this ipppd's interface when it comes
204 up.
205 -detach
207 Don't fork to become a background process (otherwise ipppd will
208 do so if a serial device other than its controlling terminal is
209 specified).
210 domain <d>
212 Append the domain name <d> to the local host name for authenti‐
213 cation purposes. For example, if gethostname() returns the name
214 porsche, but the fully qualified domain name is
215 porsche.Quotron.COM, you would use the domain option to set the
216 domain name to Quotron.COM.
217 file <f>
219 Read options from file <f> (the format is described below).
220 -ip Disable IP address negotiation. If this option is used, the
222 remote IP address must be specified with an option on the com‐
223 mand line or in an options file.
224 +ip-protocol
226 Enable the IPCP and IP protocols. This is the default condition.
227 This option is only needed if the default setting is -ip-proto‐
228 col.
229 -ip-protocol
231 Disable the IPCP and IP protocols. This should only be used if
232 you know that you are using a client which only understands IPX
233 and you don't want to confuse the client with the IPCP protocol.
234 +ipx-protocol
236 Enable the IPXCP and IPX protocols. This is the default condi‐
237 tion if your kernel supports IPX. This option is only needed if
238 the default setting is -ipx-protocol. If your kernel does not
239 support IPX then this option will have no effect.
240 -ipx-protocol
242 Disable the IPXCP and IPX protocols. This should only be used if
243 you know that you are using a client which only understands IP
244 and you don't want to confuse the client with the IPXCP proto‐
245 col.
246 ipcp-accept-local
248 With this option, ipppd will accept the peer's idea of our local
249 IP address, even if the local IP address was specified in an
250 option.
251 ipcp-accept-remote
253 With this option, ipppd will accept the peer's idea of its
254 (remote) IP address, even if the remote IP address was specified
255 in an option.
256 ipcp-max-configure <n>
258 Set the maximum number of IPCP configure-request transmissions
259 to <n> (default 10).
260 ipcp-max-failure <n>
262 Set the maximum number of IPCP configure-NAKs returned before
263 starting to send configure-Rejects instead to <n> (default 10).
264 ipcp-max-terminate <n>
266 Set the maximum number of IPCP terminate-request transmissions
267 to <n> (default 3).
268 ipcp-restart <n>
270 Set the IPCP restart interval (retransmission timeout) to <n>
271 seconds (default 3).
272 ipparam string
274 Provides an extra parameter to the ip-up and ip-down scripts.
275 If this option is given, the string supplied is given as the 6th
276 parameter to those scripts.
277 ipx-network <n>
279 Set the IPX network number in the IPXCP configure request frame
280 to <n>. There is no valid default. If this option is not speci‐
281 fied then the network number is obtained from the peer. If the
282 peer does not have the network number, the IPX protocol will not
283 be started. This is a hexadecimal number and is entered without
284 any leading sequence such as 0x. It is related to the ipxcp-
285 accept-network option.
286 ipx-node <n>:<m>
288 Set the IPX node numbers. The two node numbers are separated
289 from each other with a colon character. The first number <n> is
290 the local node number. The second number <m> is the peer's node
291 number. Each node number is a hexadecimal number, to the maximum
292 of ten significant digits. The node numbers on the ipx-network
293 must be unique. There is no valid default. If this option is not
294 specified then the node number is obtained from the peer. This
295 option is a related to the ipxcp-accept-local and ipxcp-accept-
296 remote options.
297 ipx-router-name <string>
299 Set the name of the router. This is a string and is sent to the
300 peer as information data.
301 ipx-routing <n>
303 Set the routing protocol to be received by this option. Use a
304 comma-serperated list if you want to specify more than one pro‐
305 tocol. The 'none' option (0) may be specified as the only
306 instance of ipx-routing. The values may be 0 for NONE, 2 for
307 RIP/SAP, and 4 for NLSP.
308 ipxcp-accept-local
310 Accept the peer's NAK for the node number specified in the ipx-
311 node option. If a node number was specified, and non-zero, the
312 default is to insist that the value be used. If you include this
313 option then you will permit the peer to override the entry of
314 the node number.
315 ipxcp-accept-network
317 Accept the peer's NAK for the network number specified in the
318 ipx-network option. If a network number was specified, and non-
319 zero, the default is to insist that the value be used. If you
320 include this option then you will permit the peer to override
321 the entry of the node number.
322 ipxcp-accept-remote
324 Use the peer's network number specified in the configure request
325 frame. If a node number was specified for the peer and this
326 option was not specified, the peer will be forced to use the
327 value which you have specified.
328 ipxcp-max-configure <n>
330 Set the maximum number of IPXCP configure request frames which
331 the system will send to <n>. The default is 10.
332 ipxcp-max-failure <n>
334 Set the maximum number of IPXCP NAK frames which the local sys‐
335 tem will send before it rejects the options. The default value
336 is 3.
337 ipxcp-max-terminate <n>
339 Set the maximum nuber of IPXCP terminate request frames before
340 the local system considers that the peer is not listening to
341 them. The default value is 3.
342 kdebug n
344 Enable debugging code in the kernel-level PPP driver. The argu‐
345 ment n is a number which is the sum of the following values: 1
346 to enable general debug messages, 2 to request that the contents
347 of received packets be printed, and 4 to request that the con‐
348 tents of transmitted packets be printed.
349 lcp-echo-failure <n>
351 If this option is given, ipppd will presume the peer to be dead
352 if n LCP echo-requests are sent without receiving a valid LCP
353 echo-reply. If this happens, ipppd will terminate the connec‐
354 tion. Use of this option requires a non-zero value for the lcp-
355 echo-interval parameter. This option can be used to enable
356 ipppd to terminate after the physical connection has been broken
357 (e.g., the line hung up) in situations where no hardware modem
358 control lines are available.
359 lcp-echo-interval <n>
361 If this option is given, ipppd will send an LCP echo-request
362 frame to the peer every n seconds. With Linux, the echo-request
363 is sent when no packets have been received from the peer for n
364 seconds. Normally the peer should respond to the echo-request
365 by sending an echo-reply. This option can be used with the lcp-
366 echo-failure option to detect that the peer is no longer con‐
367 nected.
368 lcp-max-configure <n>
370 Set the maximum number of LCP configure-request transmissions to
371 <n> (default 10).
372 lcp-max-failure <n>
374 Set the maximum number of LCP configure-NAKs returned before
375 starting to send configure-Rejects instead to <n> (default 10).
376 lcp-max-terminate <n>
378 Set the maximum number of LCP terminate-request transmissions to
379 <n> (default 3).
380 lcp-restart <n>
382 Set the LCP restart interval (retransmission timeout) to <n>
383 seconds (default 3).
384 lock Specifies that ipppd should create a UUCP-style lock file for
386 the serial device to ensure exclusive access to the device.
387 login Use the system password database for authenticating the peer
389 using PAP, and record the user in the system wtmp file.
390 -mn Disable magic number negotiation. With this option, ipppd can‐
392 not detect a looped-back line.
393 +mp enables MPPP negotiation
395 mru <n>
397 Set the MRU [Maximum Receive Unit] value to <n> for negotiation.
398 ipppd will ask the peer to send packets of no more than <n>
399 bytes. The minimum MRU value is 128. The default MRU value is
400 1500. A value of 296 is recommended for slow links (40 bytes
401 for TCP/IP header + 256 bytes of data).
402 -mru Disable MRU [Maximum Receive Unit] negotiation. With this
404 option, ipppd will use the default MRU value of 1500 bytes.
405 ms-dns <n>
407 This option sets the IP address or addresses for the Domain Name
408 Server. It is used by Microsoft Windows clients. The primary DNS
409 address is specified by the first instance of the ms-dns option.
410 The secondary is specified by the second instance.
411 ms-get-dns
413 Implements the client side of RFC1877. If ipppd is acting as a
414 client to a server that implements RFC1877 such as one intended
415 to be used with Microsoft Windows clients, this option allows
416 ipppd to obtain one or two DNS (Domain Name Server) addresses
417 from the server. It does not do anything with these addresses
418 except put them in the environment (MS_DNS1 MS_DNS2) that is
419 passed to scripts. For compatibility with the async pppd, DNS1
420 DNS2 environment variables are also set. A sample resolv.conf is
421 created in /etc/ppp/resolv.conf. The /etc/ppp/ip-up script
422 should use this information to perform whatever adjustment is
423 necessary. Note: RFC1877 is a horrible protocol layering viola‐
424 tion, the correct approach would be to use DHCP after the IPCP
425 phase.
426 ms-get-wins
428 As ms-get-dns but for WINS (Windows Internet Name Services)
429 server addresses. Environment variables are MS_WINS1 and
430 MS_WINS2.
431 mtu <n>
433 Set the MTU [Maximum Transmit Unit] value to <n>. Unless the
434 peer requests a smaller value via MRU negotiation, ipppd will
435 request that the kernel networking code send data packets of no
436 more than n bytes through the PPP network interface.
437 name <n>
439 Set the name of the local system for authentication purposes to
440 <n>.
441 netmask <n>
443 Set the interface netmask to <n>, a 32 bit netmask in "decimal
444 dot" notation (e.g. 255.255.255.0). If this option is given,
445 the value specified is ORed with the default netmask. The
446 default netmask is chosen based on the negotiated remote IP
447 address; it is the appropriate network mask for the class of the
448 remote IP address, ORed with the netmasks for any non point-to-
449 point network interfaces in the system which are on the same
450 network.
451 noipdefault
453 Disables the default behaviour when no local IP address is spec‐
454 ified, which is to determine (if possible) the local IP address
455 from the hostname. With this option, the peer will have to sup‐
456 ply the local IP address during IPCP negotiation (unless it
457 specified explicitly on the command line or in an options file).
458 passive
460 Enables the "passive" option in the LCP. With this option,
461 ipppd will attempt to initiate a connection; if no reply is
462 received from the peer, ipppd will then just wait passively for
463 a valid LCP packet from the peer (instead of exiting, as it does
464 without this option).
465 -p Same as the passive option.
467 +pap Require the peer to authenticate itself using PAP.
469 -pap Don't agree to authenticate using PAP.
471 papcrypt
473 Indicates that all secrets in the /etc/ppp/pap-secrets file
474 which are used for checking the identity of the peer are
475 encrypted, and thus ipppd should not accept a password which
476 (before encryption) is identical to the secret from the
477 /etc/ppp/pap-secrets file.
478 pap-max-authreq <n>
480 Set the maximum number of PAP authenticate-request transmissions
481 to <n> (default 10).
482 pap-restart <n>
484 Set the PAP restart interval (retransmission timeout) to <n>
485 seconds (default 3).
486 pap-timeout <n>
488 Set the maximum time that ipppd will wait for the peer to
489 authenticate itself with PAP to <n> seconds (0 means no limit).
490 pass-filter filter-expression
492 Specifies a packet filter to applied to data packets being sent
493 or received to determine which packets should be allowed to
494 pass. Packets which are rejected by the filter are silently
495 discarded. This option can be used to prevent specific network
496 daemons (such as routed) using up link bandwidth, or to provide
497 a basic firewall capability. The filter-expression syntax is as
498 described for tcpdump(1), except that qualifiers which are inap‐
499 propriate for a PPP link, such as ether and arp, are not permit‐
500 ted. Generally the filter expression should be enclosed in sin‐
501 gle-quotes to prevent whitespace in the expression from being
502 interpreted by the shell. Note that it is possible to apply dif‐
503 ferent constraints to incoming and outgoing packets using the
504 inbound and outbound qualifiers. This option is currently only
505 available if both the kernel and ipppd were compiled with
506 IPPP_FILTER defined.
507 -pc Disable protocol field compression negotiation (use default,
509 i.e. protocol field compression disabled).
510 pidfile <filename>
512 Use <filename> instead of /var/run/ipppd.pid
513 pred1comp
515 Attempt to request that the peer send the local system frames
516 which have been compressed by the Predictor-1 compression. The
517 compression protocols must be loaded or this option will be
518 ignored.
519 -pred1comp
521 Do not accept Predictor-1 comprssion, even if the peer wants to
522 send this type of compression and support has been defined in
523 the kernel.
524 proxyarp
526 Add an entry to this system's ARP [Address Resolution Protocol]
527 table with the IP address of the peer and the Ethernet address
528 of this system.
529 -proxyarp
531 Disable the proxyarp option. The system administrator who
532 wishes to prevent users from creating proxy ARP entries with
533 ipppd can do so by placing this option in the /etc/ppp/ioptions
534 file.
535 remotename <n>
537 Set the assumed name of the remote system for authentication
538 purposes to <n>.
539 set_userip
541 You may define valid IPs in /etc/ppp/useriptab
542 silent With this option, ipppd will not transmit LCP packets to initi‐
544 ate a connection until a valid LCP packet is received from the
545 peer (as for the `passive' option with ancient versions of
546 ipppd).
547 +ua <p>
549 Agree to authenticate using PAP [Password Authentication Proto‐
550 col] if requested by the peer, and use the data in file <p> for
551 the user and password to send to the peer. The file contains the
552 remote user name, followed by a newline, followed by the remote
553 password, followed by a newline. This option is obsolescent.
554 usefirstip
556 Gets the remote address from the first entry in the auth file
557 (if there is an IP address entry). This address should be a full
558 IP address not an address from a masked area. Ipppd calls
559 'gethostbyname()' and negotiates the result. IP from auth file
560 will overwrite the remote address gotten from the interface.
561 'usefirstip' is UNTESTED!
562 usehostname
564 Enforce the use of the hostname as the name of the local system
565 for authentication purposes (overrides the name option).
566 usepeerdns
568 Same as ms-get-dns for compatibility with async pppd.
569 user <u>
571 Set the user name to use for authenticating this machine with
572 the peer using PAP to <u>.
573 useifip
575 will get (if not set to 0.0.0.0) the IP address for the negotia‐
576 tion from the attached network-interface. (also: ipppd will try
577 to negotiate 'pointopoint' IP as remote IP) interface address ->
578 local IP pointopoint address -> remote IP
579 -vj Disable negotiation of Van Jacobson style TCP/IP header compres‐
581 sion (use default, i.e. no compression).
582 -vjccomp
584 Disable the connection-ID compression option in Van Jacobson
585 style TCP/IP header compression. With this option, ipppd will
586 not omit the connection-ID byte from Van Jacobson compressed
587 TCP/IP headers, nor ask the peer to do so.
588 vj-max-slots n
590 Sets the number of connection slots to be used by the Van Jacob‐
591 son TCP/IP header compression and decompression code to n, which
592 must be between 2 and 16 (inclusive).
593
595 Options can be taken from files as well as the command line. ipppd
596 reads options from the file /etc/ppp/ioptions before looking at the
597 command line. An options file is parsed into a series of words, delim‐
598 ited by whitespace. Whitespace can be included in a word by enclosing
599 the word in quotes ("). A backslash (\) quotes the following charac‐
600 ter. A hash (#) starts a comment, which continues until the end of the
601 line.
602
604 ipppd provides system administrators with sufficient access control
605 that PPP access to a server machine can be provided to legitimate users
606 without fear of compromising the security of the server or the network
607 it's on. In part this is provided by the /etc/ppp/ioptions file, where
608 the administrator can place options to require authentication whenever
609 ipppd is run, and in part by the PAP and CHAP secrets files, where the
610 administrator can restrict the set of IP addresses which individual
611 users may use.
612 The default behaviour of ipppd is to agree to authenticate if
614 requested, and to not require authentication from the peer. However,
615 ipppd will not agree to authenticate itself with a particular protocol
616 if it has no secrets which could be used to do so.
617 Authentication is based on secrets, which are selected from secrets
619 files (/etc/ppp/pap-secrets for PAP, /etc/ppp/chap-secrets for CHAP).
620 Both secrets files have the same format, and both can store secrets for
621 several combinations of server (authenticating peer) and client (peer
622 being authenticated). Note that ipppd can be both a server and client,
623 and that different protocols can be used in the two directions if
624 desired.
625 A secrets file is parsed into words as for a options file. A secret is
627 specified by a line containing at least 3 words, in the order client
628 name, server name, secret. Any following words on the same line are
629 taken to be a list of acceptable IP addresses for that client. If
630 there are only 3 words on the line, it is assumed that any IP address
631 is OK; to disallow all IP addresses, use "-". If the secret starts
632 with an `@', what follows is assumed to be the name of a file from
633 which to read the secret. A "*" as the client or server name matches
634 any name. When selecting a secret, ipppd takes the best match, i.e.
635 the match with the fewest wildcards.
636 Thus a secrets file contains both secrets for use in authenticating
638 other hosts, plus secrets which we use for authenticating ourselves to
639 others. Which secret to use is chosen based on the names of the host
640 (the `local name') and its peer (the `remote name'). The local name is
641 set as follows:
642 if the usehostname option is given,
644 then the local name is the hostname of this machine (with the domain
645 appended, if given)
646 else if the name option is given,
648 then use the argument of the first name option seen
649 else if the local IP address is specified with a hostname,
651 then use that name
652 else use the hostname of this machine (with the domain appended, if
654 given)
655 When authenticating ourselves using PAP, there is also a `username'
657 which is the local name by default, but can be set with the user option
658 or the +ua option.
659 The remote name is set as follows:
661 if the remotename option is given,
663 then use the argument of the last remotename option seen
664 else if the remote IP address is specified with a hostname,
666 then use that host name
667 else the remote name is the null string "".
669 Secrets are selected from the PAP secrets file as follows:
671 * For authenticating the peer, look for a secret with client == user‐
673 name specified in the PAP authenticate-request, and server == local
674 name.
675 * For authenticating ourselves to the peer, look for a secret with
677 client == our username, server == remote name.
678 When authenticating the peer with PAP, a secret of "" matches any pass‐
680 word supplied by the peer. If the password doesn't match the secret,
681 the password is encrypted using crypt() and checked against the secret
682 again; thus secrets for authenticating the peer can be stored in
683 encrypted form. If the papcrypt option is given, the first (unen‐
684 crypted) comparison is omitted, for better security.
685 If the login option was specified, the username and password are also
687 checked against the system password database. Thus, the system admin‐
688 istrator can set up the pap-secrets file to allow PPP access only to
689 certain users, and to restrict the set of IP addresses that each user
690 can use. Typically, when using the login option, the secret in
691 /etc/ppp/pap-secrets would be "", to avoid the need to have the same
692 secret in two places.
693 Secrets are selected from the CHAP secrets file as follows:
695 * For authenticating the peer, look for a secret with client == name
697 specified in the CHAP-Response message, and server == local name.
698 * For authenticating ourselves to the peer, look for a secret with
700 client == local name, and server == name specified in the CHAP-Chal‐
701 lenge message.
702 Authentication must be satisfactorily completed before IPCP (or any
704 other Network Control Protocol) can be started. If authentication
705 fails, ipppd will terminated the link (by closing LCP). If IPCP nego‐
706 tiates an unacceptable IP address for the remote host, IPCP will be
707 closed. IP packets can only be sent or received when IPCP is open.
708 In some cases it is desirable to allow some hosts which can't authenti‐
710 cate themselves to connect and use one of a restricted set of IP
711 addresses, even when the local host generally requires authentication.
712 If the peer refuses to authenticate itself when requested, ipppd takes
713 that as equivalent to authenticating with PAP using the empty string
714 for the username and password. Thus, by adding a line to the pap-
715 secrets file which specifies the empty string for the client and pass‐
716 word, it is possible to allow restricted access to hosts which refuse
717 to authenticate themselves.
718
720 When IPCP negotiation is completed successfully, ipppd will inform the
721 kernel of the local and remote IP addresses for the ppp interface.
722 This is sufficient to create a host route to the remote end of the
723 link, which will enable the peers to exchange IP packets. Communica‐
724 tion with other machines generally requires further modification to
725 routing tables and/or ARP (Address Resolution Protocol) tables. In
726 some cases this will be done automatically through the actions of the
727 routed or gated daemons, but in most cases some further intervention is
728 required.
729 Sometimes it is desirable to add a default route through the remote
731 host, as in the case of a machine whose only connection to the Internet
732 is through the ppp interface. The defaultroute option causes ipppd to
733 create such a default route when IPCP comes up, and delete it when the
734 link is terminated.
735 In some cases it is desirable to use proxy ARP, for example on a server
737 machine connected to a LAN, in order to allow other hosts to communi‐
738 cate with the remote host. The proxyarp option causes ipppd to look
739 for a network interface on the same subnet as the remote host (an
740 interface supporting broadcast and ARP, which is up and not a point-to-
741 point or loopback interface). If found, ipppd creates a permanent,
742 published ARP entry with the IP address of the remote host and the
743 hardware address of the network interface found.
744
746 Messages are sent to the syslog daemon using facility LOG_DAEMON.
747 (This can be overriden by recompiling ipppd with the macro LOG_PPP
748 defined as the desired facility.) In order to see the error and debug
749 messages, you will need to edit your /etc/syslog.conf file to direct
750 the messages to the desired output device or file.
751 The debug option causes the contents of all control packets sent or
753 received to be logged, that is, all LCP, PAP, CHAP or IPCP packets.
754 This can be useful if the PPP negotiation does not succeed. If debug‐
755 ging is enabled at compile time, the debug option also causes other
756 debugging messages to be logged.
757 Debugging can also be enabled or disabled by sending a SIGUSR1 to the
759 ipppd process. This signal acts as a toggle.
760
762 /var/run/ipppd.pid
763 Process-ID for ipppd process on ppp interface unit n.
764 /etc/ppp/ip-up
766 A program or script which is executed when the link is available
767 for sending and receiving IP packets (that is, IPCP has come
768 up). It is executed with the parameters
769 interface-name tty-device speed local-IP-address remote-IP-
771 address
772 and with its standard input, output and error streams redirected
774 to /dev/null.
775 This program or script is executed with the same real and effec‐
777 tive user-ID as ipppd, that is, at least the effective user-ID
778 and possibly the real user-ID will be root. This is so that it
779 can be used to manipulate routes, run privileged daemons (e.g.
780 sendmail), etc. Be careful that the contents of the
781 /etc/ppp/ip-up and /etc/ppp/ip-down scripts do not compromise
782 your system's security.
783 /etc/ppp/ip-down
785 A program or script which is executed when the link is no longer
786 available for sending and receiving IP packets. This script can
787 be used for undoing the effects of the /etc/ppp/ip-up script.
788 It is invoked with the same parameters as the ip-up script, and
789 the same security considerations apply, since it is executed
790 with the same effective and real user-IDs as ipppd.
791 /etc/ppp/ipx-up
793 A program or script which is executed when the link is available
794 for sending and receiving IPX packets (that is, IPXCP has come
795 up). It is executed with the parameters
796 interface-name tty-device speed network-number local-IPX-node-
798 address remote-IPX-node-address local-IPX-routing-protocol
799 remote-IPX-routing-protocol local-IPX-router-name remote-IPX-
800 router-name ipparam ipppd-pid
801 and with its standard input, output and error streams redirected
803 to /dev/null.
804 The local-IPX-routing-protocol and remote-IPX-routing-protocol
806 field may be one of the following:
807 NONE to indicate that there is no routing protocol
809 RIP to indicate that RIP/SAP should be used
810 NLSP to indicate that Novell NLSP should be used
811 RIP NLSP to indicate that both RIP/SAP and NLSP should be used
812 This program or script is executed with the same real and effec‐
814 tive user-ID as ipppd, that is, at least the effective user-ID
815 and possibly the real user-ID will be root. This is so that it
816 can be used to manipulate routes, run privileged daemons (e.g.
817 ripd), etc. Be careful that the contents of the /etc/ppp/ipx-up
818 and /etc/ppp/ipx-down scripts do not compromise your system's
819 security.
820 /etc/ppp/ipx-down
822 A program or script which is executed when the link is no longer
823 available for sending and receiving IPX packets. This script
824 can be used for undoing the effects of the /etc/ppp/ipx-up
825 script. It is invoked with the same parameters as the ipx-up
826 script, and the same security considerations apply, since it is
827 executed with the same effective and real user-IDs as ipppd.
828 /etc/ppp/auth-up
830 This program or script is executed after successful authentica‐
831 tion with the following parameters: interface name, authentica‐
832 tion user name, username of ipppd, devicename, speed, remote
833 number
834 /etc/ppp/auth-down
836 This program or script is executed after a disconnection with
837 the following parameters: interface name, authentication user
838 name, username of ipppd, devicename, speed, remote number
839 /etc/ppp/auth-fail
841 This program or script is executed after a authentication fail‐
842 ure with the following parameters: interface name, authentica‐
843 tion user name, username of ipppd, devicename, speed, remote
844 number, failure reason
845 Valid reasons are:
846 1 = Timeout during pap auth
847 2 = pap protocol rejected
848 3 = pap secrets invalid
849 9 = Timeout during chap auth
850 10 = chap protocol rejected
851 11 = chap secrets invalid
852 /etc/ppp/pap-secrets
854 Usernames, passwords and IP addresses for PAP authentication.
855 /etc/ppp/chap-secrets
857 Names, secrets and IP addresses for CHAP authentication.
858 /etc/ppp/ioptions
860 System default options for ipppd, read before user default
861 options or command-line options.
862
864 ttyI(4), isdnctrl(8), ipppstats(8),
865 RFC1144
867 Jacobson, V. Compressing TCP/IP headers for low-speed serial
868 links. 1990 February.
869 RFC1321
871 Rivest, R. The MD5 Message-Digest Algorithm. 1992 April.
872 RFC1332
874 McGregor, G. PPP Internet Protocol Control Protocol (IPCP).
875 1992 May.
876 RFC1334
878 Lloyd, B.; Simpson, W.A. PPP authentication protocols. 1992
879 October.
880 RFC1548
882 Simpson, W.A. The Point-to-Point Protocol (PPP). 1993 Decem‐
883 ber.
884 RFC1549
886 Simpson, W.A. PPP in HDLC Framing. 1993 December
887
889 The following signals have the specified effect when sent to the ipppd
890 process.
891 SIGINT, SIGTERM
893 These signals cause ipppd to terminate the link (by closing
894 LCP), restore the serial device settings, and exit.
895 SIGHUP This signal causes ipppd to terminate the link, restore the
897 serial device settings, and close the serial device. If the
898 persist option has been specified, ipppd will try to reopen the
899 serial device and start another connection. Otherwise ipppd
900 will exit.
901 SIGUSR2
903 This signal causes ipppd to renegotiate compression. This can
904 be useful to re-enable compression after it has been disabled as
905 a result of a fatal decompression error. With the BSD Compress
906 scheme, fatal decompression errors generally indicate a bug in
907 one or other implementation.
908
910 Originally written by Drew Perkins, Brad Clements, Karl Fox, Greg
911 Christy, Brad Parker, Paul Mackerras <paulus@cs.anu.edu.au> for (origi‐
912 nal) pppd.
913 Changes for ipppd by Klaus Franken <kfr@suse.de> and Michael Hipp
915 <Michael.Hipp@student.uni-tuebingen.de>.
916 Removal of pppd specific options and polish by Frank Elsner
918 <Elsner@zrz.TU-Berlin.DE>.
919isdn4k-utils-3.13 2003/07/01 IPPPD(8)