2 .\" Copyright (c) 2001 Brian Somers <brian@Awfulhak.org>
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33 .Nd Point to Point Protocol (a.k.a. user-ppp)
42 This is a user process
47 is implemented as a part of the kernel (e.g., as managed by
49 and it is thus somewhat hard to debug and/or modify its behaviour.
50 However, in this implementation
52 is done as a user process with the help of the
53 tunnel device driver (tun).
57 flag does the equivalent of a
61 network address translation features.
64 to act as a NAT or masquerading engine for all machines on an internal
68 for details on the technical side of the NAT engine.
70 .Sx NETWORK ADDRESS TRANSLATION (PACKET ALIASING)
71 section of this manual page for details on how to configure NAT in
78 to be silent at startup rather than displaying the mode and interface
85 to only attempt to open
86 .Pa /dev/tun Ns Ar N .
89 will start with a value of 0 for
91 and keep trying to open a tunnel device by incrementing the value of
93 by one each time until it succeeds.
94 If it fails three times in a row
95 because the device file is missing, it gives up.
101 .Bl -tag -width XXX -offset XXX
104 opens the tun interface, configures it then goes into the background.
105 The link is not brought up until outgoing data is detected on the tun
106 interface at which point
108 attempts to bring up the link.
109 Packets received (including the first one) while
111 is trying to bring the link up will remain queued for a default of
121 must be given on the command line (see below) and a
123 must be done in the system profile that specifies a peer IP address to
124 use when configuring the interface.
127 is usually appropriate.
131 .Pa /usr/share/examples/ppp/ppp.conf.sample
136 attempts to establish a connection with the peer immediately.
139 goes into the background and the parent process returns an exit code
143 exits with a non-zero result.
147 attempts to establish a connection with the peer immediately, but never
149 The link is created in background mode.
150 This is useful if you wish to control
152 invocation from another process.
154 This is used for communicating over an already established connection,
155 usually when receiving incoming connections accepted by
160 line and uses descriptor 0 as the link.
162 will also ignore any configured chat scripts unless the
164 option has been enabled.
166 If callback is configured,
170 information when dialing back.
176 will behave slightly differently if descriptor 0 was created by
178 As pipes are not bi-directional, ppp will redirect all writes to descriptor
179 1 (standard output), leaving only reads acting on descriptor 0.
180 No special action is taken if descriptor 0 was created by
183 This option is designed for machines connected with a dedicated
186 will always keep the device open and will ignore any configured
187 chat scripts unless the
189 option has been enabled.
191 This mode is equivalent to
195 will bring the link back up any time it is dropped for any reason.
197 This is a no-op, and gives the same behaviour as if none of the above
198 modes have been specified.
200 loads any sections specified on the command line then provides an
204 One or more configuration entries or systems
206 .Pa /etc/ppp/ppp.conf )
207 may also be specified on the command line.
212 .Pa /etc/ppp/ppp.conf
213 at startup, followed by each of the systems specified on the command line.
216 .It Provides an interactive user interface.
217 Using its command mode, the user can
218 easily enter commands to establish the connection with the remote end, check
219 the status of connection and close the connection.
220 All functions can also be optionally password protected for security.
221 .It Supports both manual and automatic dialing.
222 Interactive mode has a
224 command which enables you to talk to the device directly.
225 When you are connected to the remote peer and it starts to talk
228 detects it and switches to packet mode automatically.
230 determined the proper sequence for connecting with the remote host, you
231 can write a chat script to {define} the necessary dialing and login
232 procedure for later convenience.
233 .It Supports on-demand dialup capability.
238 will act as a daemon and wait for a packet to be sent over the
241 When this happens, the daemon automatically dials and establishes the
243 In almost the same manner
245 mode (direct-dial mode) also automatically dials and establishes the
247 However, it differs in that it will dial the remote site
248 any time it detects the link is down, even if there are no packets to be
250 This mode is useful for full-time connections where we worry less
251 about line charges and more about being connected full time.
254 mode is also available.
255 This mode is targeted at a dedicated link between two machines.
257 will never voluntarily quit from dedicated mode - you must send it the
259 command via its diagnostic socket.
262 will force an LCP renegotiation, and a
264 will force it to exit.
265 .It Supports client callback.
267 can use either the standard LCP callback protocol or the Microsoft
268 CallBack Control Protocol (https://winprotocoldoc.blob.core.windows.net/productionwindowsarchives/MS-CBCP/[MS-CBCP].pdf).
269 .It Supports NAT or packet aliasing.
270 Packet aliasing (a.k.a.\& IP masquerading) allows computers on a
271 private, unregistered network to access the Internet.
274 host acts as a masquerading gateway.
275 IP addresses as well as TCP and
276 UDP port numbers are NAT'd for outgoing packets and de-NAT'd for
278 .It Supports background PPP connections.
279 In background mode, if
281 successfully establishes the connection, it will become a daemon.
282 Otherwise, it will exit with an error.
283 This allows the setup of
284 scripts that wish to execute certain commands only if the connection
285 is successfully established.
286 .It Supports server-side PPP connections.
289 acts as server which accepts incoming
291 connections on stdin/stdout.
292 .It Supports PAP and CHAP (rfc 1994, 2433 and 2759) authentication.
293 With PAP or CHAP, it is possible to skip the Unix style
295 procedure, and use the
297 protocol for authentication instead.
298 If the peer requests Microsoft CHAP authentication and
300 is compiled with DES support, an appropriate MD4/DES response will be
302 .It Supports RADIUS (rfc 2138 & 2548) authentication.
303 An extension to PAP and CHAP,
310 allows authentication information to be stored in a central or
311 distributed database along with various per-user framed connection
315 is available at compile time,
319 requests when configured to do so.
320 .It Supports Proxy Arp.
322 can be configured to make one or more proxy arp entries on behalf of
324 This allows routing from the peer to the LAN without
325 configuring each machine on that LAN.
326 .It Supports packet filtering.
327 User can {define} four kinds of filters: the
329 filter for incoming packets, the
331 filter for outgoing packets, the
333 filter to {define} a dialing trigger packet and the
335 filter for keeping a connection alive with the trigger packet.
336 .It Tunnel driver supports bpf.
339 to check the packet flow over the
342 .It Supports PPP over TCP and PPP over UDP.
343 If a device name is specified as
344 .Em host Ns No : Ns Em port Ns
349 will open a TCP or UDP connection for transporting data rather than using a
350 conventional serial device.
351 UDP connections force
353 into synchronous mode.
354 .It Supports PPP over Ethernet (rfc 2516).
357 is given a device specification of the format
358 .No PPPoE: Ns Ar iface Ns Xo
359 .Op \&: Ns Ar provider Ns
373 On systems that do not support
375 an external program such as
378 .It "Supports IETF draft Predictor-1 (rfc 1978) and DEFLATE (rfc 1979) compression."
380 supports not only VJ-compression but also Predictor-1 and DEFLATE compression.
381 Normally, a modem has built-in compression (e.g., v42.bis) and the system
382 may receive higher data rates from it as a result of such compression.
383 While this is generally a good thing in most other situations, this
384 higher speed data imposes a penalty on the system by increasing the
385 number of serial interrupts the system has to process in talking to the
386 modem and also increases latency.
387 Unlike VJ-compression, Predictor-1 and DEFLATE compression pre-compresses
389 network traffic flowing through the link, thus reducing overheads to a
391 .It Supports Microsoft's IPCP extensions (rfc 1877).
392 Name Server Addresses and NetBIOS Name Server Addresses can be negotiated
393 with clients using the Microsoft
395 stack (i.e., Win95, WinNT)
396 .It Supports Multi-link PPP (rfc 1990)
397 It is possible to configure
399 to open more than one physical connection to the peer, combining the
400 bandwidth of all links for better throughput.
401 .It Supports MPPE (draft-ietf-pppext-mppe)
402 MPPE is Microsoft Point to Point Encryption scheme.
403 It is possible to configure
405 to participate in Microsoft's Windows VPN.
408 can only get encryption keys from CHAP 81 authentication.
410 must be compiled with DES for MPPE to operate.
411 .It Supports IPV6CP (rfc 2023).
412 An IPv6 connection can be made in addition to or instead of the normal
425 will not run if the invoking user id is not zero.
426 This may be overridden by using the
429 .Pa /etc/ppp/ppp.conf .
430 When running as a normal user,
432 switches to user id 0 in order to alter the system routing table, set up
433 system lock files and read the ppp configuration files.
434 All external commands (executed via the "shell" or "!bg" commands) are executed
435 as the user id that invoked
439 logging facility if you are interested in what exactly is done as user id
444 you may need to deal with some initial configuration details.
447 Make sure that your system has a group named
451 file and that the group contains the names of all users expected to use
455 manual page for details.
456 Each of these users must also be given access using the
459 .Pa /etc/ppp/ppp.conf .
466 A common log file name is
467 .Pa /var/log/ppp.log .
468 To make output go to this file, put the following lines in the
471 .Bd -literal -offset indent
473 *.*<TAB>/var/log/ppp.log
476 It is possible to have more than one
478 log file by creating a link to the
486 .Bd -literal -offset indent
488 *.*<TAB>/var/log/ppp0.log
492 .Pa /etc/syslog.conf .
493 Do not forget to send a
498 .Pa /etc/syslog.conf .
500 Although not strictly relevant to
502 operation, you should configure your resolver so that it works correctly.
503 This can be done by configuring a local DNS
506 or by adding the correct
509 .Pa /etc/resolv.conf .
512 manual page for details.
514 Alternatively, if the peer supports it,
516 can be configured to ask the peer for the nameserver address(es) and to
524 commands below for details.
527 In the following examples, we assume that your machine name is
533 above) with no arguments, you are presented with a prompt:
534 .Bd -literal -offset indent
540 part of your prompt should always be in upper case.
541 If it is in lower case, it means that you must supply a password using the
544 This only ever happens if you connect to a running version of
546 and have not authenticated yourself using the correct password.
548 You can start by specifying the device name and speed:
549 .Bd -literal -offset indent
550 ppp ON awfulhak> set device /dev/cuau0
551 ppp ON awfulhak> set speed 38400
554 Normally, hardware flow control (CTS/RTS) is used.
556 certain circumstances (as may happen when you are connected directly
557 to certain PPP-capable terminal servers), this may result in
559 hanging as soon as it tries to write data to your communications link
560 as it is waiting for the CTS (clear to send) signal - which will never
562 Thus, if you have a direct line and cannot seem to make a
563 connection, try turning CTS/RTS off with
565 If you need to do this, check the
567 description below too - you will probably need to
568 .Dq set accmap 000a0000 .
570 Usually, parity is set to
575 Parity is a rather archaic error checking mechanism that is no
576 longer used because modern modems do their own error checking, and most
577 link-layer protocols (that is what
579 is) use much more reliable checking mechanisms.
580 Parity has a relatively
581 huge overhead (a 12.5% increase in traffic) and as a result, it is always
588 However, some ISPs (Internet Service Providers) may use
589 specific parity settings at connection time (before
592 Notably, Compuserve insist on even parity when logging in:
593 .Bd -literal -offset indent
594 ppp ON awfulhak> set parity even
597 You can now see what your current device settings look like:
598 .Bd -literal -offset indent
599 ppp ON awfulhak> show physical
603 Link Type: interactive
609 Device List: /dev/cuau0
610 Characteristics: 38400bps, cs8, even parity, CTS/RTS on
613 0 octets in, 0 octets out
618 The term command can now be used to talk directly to the device:
619 .Bd -literal -offset indent
620 ppp ON awfulhak> term
626 Password: myisppassword
630 When the peer starts to talk in
633 detects this automatically and returns to command mode.
634 .Bd -literal -offset indent
635 ppp ON awfulhak> # No link has been established
636 Ppp ON awfulhak> # We've connected & finished LCP
637 PPp ON awfulhak> # We've authenticated
638 PPP ON awfulhak> # We've agreed IP numbers
641 If it does not, it is probable that the peer is waiting for your end to
647 configuration packets to the peer, use the
649 command to drop out of terminal mode and enter packet mode.
651 If you never even receive a login prompt, it is quite likely that the
652 peer wants to use PAP or CHAP authentication instead of using Unix-style
653 login/password authentication.
654 To set things up properly, drop back to
655 the prompt and set your authentication name and key, then reconnect:
656 .Bd -literal -offset indent
658 ppp ON awfulhak> set authname myispusername
659 ppp ON awfulhak> set authkey myisppassword
660 ppp ON awfulhak> term
667 You may need to tell ppp to initiate negotiations with the peer here too:
668 .Bd -literal -offset indent
670 ppp ON awfulhak> # No link has been established
671 Ppp ON awfulhak> # We've connected & finished LCP
672 PPp ON awfulhak> # We've authenticated
673 PPP ON awfulhak> # We've agreed IP numbers
676 You are now connected!
679 in the prompt has changed to capital letters to indicate that you have
681 If only some of the three Ps go uppercase, wait until
682 either everything is uppercase or lowercase.
683 If they revert to lowercase, it means that
685 could not successfully negotiate with the peer.
686 A good first step for troubleshooting at this point would be to
687 .Bd -literal -offset indent
688 ppp ON awfulhak> set log local phase lcp ipcp
694 command description below for further details.
695 If things fail at this point,
696 it is quite important that you turn logging on and try again.
698 important that you note any prompt changes and report them to anyone trying
701 When the link is established, the show command can be used to see how
703 .Bd -literal -offset indent
704 PPP ON awfulhak> show physical
705 * Modem related information is shown here *
706 PPP ON awfulhak> show ccp
707 * CCP (compression) related information is shown here *
708 PPP ON awfulhak> show lcp
709 * LCP (line control) related information is shown here *
710 PPP ON awfulhak> show ipcp
711 * IPCP (IP) related information is shown here *
712 PPP ON awfulhak> show ipv6cp
713 * IPV6CP (IPv6) related information is shown here *
714 PPP ON awfulhak> show link
715 * Link (high level) related information is shown here *
716 PPP ON awfulhak> show bundle
717 * Logical (high level) connection related information is shown here *
720 At this point, your machine has a host route to the peer.
722 that you can only make a connection with the host on the other side
724 If you want to add a default route entry (telling your
725 machine to send all packets without another routing entry to the other
728 link), enter the following command:
729 .Bd -literal -offset indent
730 PPP ON awfulhak> add default HISADDR
735 represents the IP address of the connected peer.
738 command fails due to an existing route, you can overwrite the existing
740 .Bd -literal -offset indent
741 PPP ON awfulhak> add! default HISADDR
744 This command can also be executed before actually making the connection.
745 If a new IP address is negotiated at connection time,
747 will update your default route accordingly.
749 You can now use your network applications (ping, telnet, ftp, etc.)
750 in other windows or terminals on your machine.
751 If you wish to reuse the current terminal, you can put
753 into the background using your standard shell suspend and background
761 section for details on all available commands.
762 .Sh AUTOMATIC DIALING
763 To use automatic dialing, you must prepare some Dial and Login chat scripts.
764 See the example definitions in
765 .Pa /usr/share/examples/ppp/ppp.conf.sample
767 .Pa /etc/ppp/ppp.conf
769 Each line contains one comment, inclusion, label or command:
772 A line starting with a
774 character is treated as a comment line.
775 Leading whitespace are ignored when identifying comment lines.
777 An inclusion is a line beginning with the word
779 It must have one argument - the file to {include}.
781 .Dq {!include} ~/.ppp.conf
782 for compatibility with older versions of
785 A label name starts in the first column and is followed by
789 A command line must contain a space or tab in the first column.
791 A string starting with the
793 character is substituted with the value of the environment variable by
795 Likewise, a string starting with the
797 character is substituted with the full path to the home directory of
798 the user account by the same name, and the
800 character by itself is substituted with the full path to the home directory
802 If you want to include a literal
806 character in a command or argument, enclose them in double quotes, e.g.,
807 .Bd -literal -offset indent
808 set password "pa$ss~word"
813 .Pa /etc/ppp/ppp.conf
814 file should consist of at least a
817 This section is always executed.
818 It should also contain
819 one or more sections, named according to their purpose, for example,
821 would represent your ISP, and
823 would represent an incoming
826 You can now specify the destination label name when you invoke
828 Commands associated with the
830 label are executed, followed by those associated with the destination
834 is started with no arguments, the
836 section is still executed.
837 The load command can be used to manually load a section from the
838 .Pa /etc/ppp/ppp.conf
840 .Bd -literal -offset indent
841 ppp ON awfulhak> load MyISP
844 Note, no action is taken by
846 after a section is loaded, whether it is the result of passing a label on
847 the command line or using the
850 Only the commands specified for that label in the configuration
852 However, when invoking
859 switches, the link mode tells
861 to establish a connection.
864 command below for further details.
866 Once the connection is made, the
868 portion of the prompt will change to
870 .Bd -literal -offset indent
873 ppp ON awfulhak> dial
879 The Ppp prompt indicates that
881 has entered the authentication phase.
882 The PPp prompt indicates that
884 has entered the network phase.
885 The PPP prompt indicates that
887 has successfully negotiated a network layer protocol and is in
891 .Pa /etc/ppp/ppp.linkup
892 file is available, its contents are executed
895 connection is established.
899 .Pa /usr/share/examples/ppp/ppp.conf.sample
900 which runs a script in the background after the connection is established
905 commands below for a description of possible substitution strings).
906 Similarly, when a connection is closed, the contents of the
907 .Pa /etc/ppp/ppp.linkdown
909 Both of these files have the same format as
910 .Pa /etc/ppp/ppp.conf .
912 In previous versions of
914 it was necessary to re-add routes such as the default route in the
920 where all routes that contain the
926 literals will automatically be updated when the values of these variables
928 .Sh BACKGROUND DIALING
929 If you want to establish a connection using
931 non-interactively (such as from a
935 job) you should use the
942 attempts to establish the connection immediately.
944 numbers are specified, each phone number will be tried once.
945 If the attempt fails,
947 exits immediately with a non-zero exit code.
950 becomes a daemon, and returns an exit status of zero to its caller.
951 The daemon exits automatically if the connection is dropped by the
952 remote system, or it receives a
956 Demand dialing is enabled with the
961 You must also specify the destination label in
962 .Pa /etc/ppp/ppp.conf
966 command to {define} the remote peers IP address.
968 .Pa /usr/share/examples/ppp/ppp.conf.sample )
969 .Bd -literal -offset indent
979 runs as a daemon but you can still configure or examine its
980 configuration by using the
983 .Pa /etc/ppp/ppp.conf ,
985 .Dq Li "set server +3000 mypasswd" )
986 and connecting to the diagnostic port as follows:
987 .Bd -literal -offset indent
988 # pppctl 3000 (assuming tun0)
990 PPP ON awfulhak> show who
991 tcp (127.0.0.1:1028) *
996 command lists users that are currently connected to
999 If the diagnostic socket is closed or changed to a different
1000 socket, all connections are immediately dropped.
1004 mode, when an outgoing packet is detected,
1006 will perform the dialing action (chat script) and try to connect
1010 mode, the dialing action is performed any time the line is found
1012 If the connect fails, the default behaviour is to wait 30 seconds
1013 and then attempt to connect when another outgoing packet is detected.
1014 This behaviour can be changed using the
1018 .No set redial Ar secs Ns
1020 .Oo - Ns Ar max Ns Oc Oc Ns
1024 .Bl -tag -width attempts -compact
1026 is the number of seconds to wait before attempting
1028 If the argument is the literal string
1030 the delay period is a random value between 1 and 30 seconds inclusive.
1032 is the number of seconds that
1034 should be incremented each time a new dial attempt is made.
1035 The timeout reverts to
1037 only after a successful connection is established.
1038 The default value for
1042 is the maximum number of times
1046 The default value for
1050 is the number of seconds to wait before attempting
1051 to dial the next number in a list of numbers (see the
1054 The default is 3 seconds.
1055 Again, if the argument is the literal string
1057 the delay period is a random value between 1 and 30 seconds.
1059 is the maximum number of times to try to connect for each outgoing packet
1060 that triggers a dial.
1061 The previous value is unchanged if this parameter is omitted.
1062 If a value of zero is specified for
1065 will keep trying until a connection is made.
1069 .Bd -literal -offset indent
1073 will attempt to connect 4 times for each outgoing packet that causes
1074 a dial attempt with a 3 second delay between each number and a 10 second
1075 delay after all numbers have been tried.
1076 If multiple phone numbers
1077 are specified, the total number of attempts is still 4 (it does not
1078 attempt each number 4 times).
1081 .Bd -literal -offset indent
1082 set redial 10+10-5.3 20
1087 to attempt to connect 20 times.
1088 After the first attempt,
1090 pauses for 10 seconds.
1091 After the next attempt it pauses for 20 seconds
1092 and so on until after the sixth attempt it pauses for 1 minute.
1093 The next 14 pauses will also have a duration of one minute.
1096 connects, disconnects and fails to connect again, the timeout starts again
1099 Modifying the dial delay is very useful when running
1103 mode on both ends of the link.
1104 If each end has the same timeout,
1105 both ends wind up calling each other at the same time if the link
1106 drops and both ends have packets queued.
1107 At some locations, the serial link may not be reliable, and carrier
1108 may be lost at inappropriate times.
1109 It is possible to have
1111 redial should carrier be unexpectedly lost during a session.
1112 .Bd -literal -offset indent
1113 set reconnect timeout ntries
1118 to re-establish the connection
1120 times on loss of carrier with a pause of
1122 seconds before each try.
1124 .Bd -literal -offset indent
1130 that on an unexpected loss of carrier, it should wait
1132 seconds before attempting to reconnect.
1133 This may happen up to
1138 The default value of ntries is zero (no reconnect).
1139 Care should be taken with this option.
1140 If the local timeout is slightly
1141 longer than the remote timeout, the reconnect feature will always be
1142 triggered (up to the given number of times) after the remote side
1143 times out and hangs up.
1144 NOTE: In this context, losing too many LQRs constitutes a loss of
1145 carrier and will trigger a reconnect.
1148 flag is specified, all phone numbers are dialed at most once until
1149 a connection is made.
1150 The next number redial period specified with the
1152 command is honoured, as is the reconnect tries value.
1154 value is less than the number of phone numbers specified, not all
1155 the specified numbers will be tried.
1156 To terminate the program, type
1157 .Bd -literal -offset indent
1158 PPP ON awfulhak> close
1159 ppp ON awfulhak> quit all
1164 command will terminate the
1168 connection but not the
1176 .Sh RECEIVING INCOMING PPP CONNECTIONS (Method 1)
1177 To handle an incoming
1179 connection request, follow these steps:
1182 Make sure the modem and (optionally)
1184 is configured correctly.
1185 .Bl -bullet -compact
1187 Use Hardware Handshake (CTS/RTS) for flow control.
1189 Modem should be set to NO echo back (ATE0) and NO results string (ATQ1).
1196 on the port where the modem is attached.
1199 .Dl ttyd1 Qo /usr/libexec/getty std.38400 Qc dialup on secure
1201 Do not forget to send a
1205 process to start the
1210 It is usually also necessary to train your modem to the same DTR speed
1212 .Bd -literal -offset indent
1214 ppp ON awfulhak> set device /dev/cuau1
1215 ppp ON awfulhak> set speed 38400
1216 ppp ON awfulhak> term
1217 deflink: Entering terminal mode on /dev/cuau1
1228 ppp ON awfulhak> quit
1232 .Pa /usr/local/bin/ppplogin
1233 file with the following contents:
1234 .Bd -literal -offset indent
1236 exec /usr/sbin/ppp -direct incoming
1243 work with stdin and stdout.
1246 to connect to a configured diagnostic port, in the same manner as with
1252 section must be set up in
1253 .Pa /etc/ppp/ppp.conf .
1257 section contains the
1259 command as appropriate.
1261 Prepare an account for the incoming user.
1263 ppp:xxxx:66:66:PPP Login User:/home/ppp:/usr/local/bin/ppplogin
1266 Refer to the manual entries for
1272 Support for IPCP Domain Name Server and NetBIOS Name Server negotiation
1273 can be enabled using the
1278 Refer to their descriptions below.
1280 .Sh RECEIVING INCOMING PPP CONNECTIONS (Method 2)
1281 This method differs in that we use
1283 to authenticate the connection rather than
1287 Configure your default section in
1289 with automatic ppp recognition by specifying the
1294 :pp=/usr/local/bin/ppplogin:\\
1298 Configure your serial device(s), enable a
1301 .Pa /usr/local/bin/ppplogin
1302 as in the first three steps for method 1 above.
1310 .Pa /etc/ppp/ppp.conf
1313 label (or whatever label
1318 .Pa /etc/ppp/ppp.secret
1319 for each incoming user:
1328 detects a ppp connection (by recognising the HDLC frame headers), it runs
1329 .Dq /usr/local/bin/ppplogin .
1333 that either PAP or CHAP are enabled as above.
1334 If they are not, you are
1335 allowing anybody to establish a ppp session with your machine
1337 a password, opening yourself up to all sorts of potential attacks.
1338 .Sh AUTHENTICATING INCOMING CONNECTIONS
1339 Normally, the receiver of a connection requires that the peer
1340 authenticates itself.
1341 This may be done using
1343 but alternatively, you can use PAP or CHAP.
1344 CHAP is the more secure of the two, but some clients may not support it.
1345 Once you decide which you wish to use, add the command
1349 to the relevant section of
1352 You must then configure the
1353 .Pa /etc/ppp/ppp.secret
1355 This file contains one line per possible client, each line
1356 containing up to five fields:
1359 .Ar hisaddr Op Ar label Op Ar callback-number
1366 specify the client username and password.
1371 and PAP is being used,
1373 will look up the password database
1375 when authenticating.
1376 If the client does not offer a suitable response based on any
1377 .Ar name Ns No / Ns Ar key
1380 authentication fails.
1382 If authentication is successful,
1385 is used when negotiating IP numbers.
1388 command for details.
1390 If authentication is successful and
1392 is specified, the current system label is changed to match the given
1394 This will change the subsequent parsing of the
1400 If authentication is successful and
1406 the client will be called back on the given number.
1407 If CBCP is being used,
1409 may also contain a list of numbers or a
1414 The value will be used in
1416 subsequent CBCP phase.
1417 .Sh PPP OVER TCP and UDP (a.k.a Tunnelling)
1420 over a serial link, it is possible to
1421 use a TCP connection instead by specifying the host, port and protocol as the
1424 .Dl set device ui-gate:6669/tcp
1426 Instead of opening a serial device,
1428 will open a TCP connection to the given machine on the given
1430 It should be noted however that
1432 does not use the telnet protocol and will be unable to negotiate
1433 with a telnet server.
1434 You should set up a port for receiving this
1436 connection on the receiving machine (ui-gate).
1437 This is done by first updating
1439 to name the service:
1441 .Dl ppp-in 6669/tcp # Incoming PPP connections over TCP
1447 how to deal with incoming connections on that port:
1449 .Dl ppp-in stream tcp nowait root /usr/sbin/ppp ppp -direct ppp-in
1451 Do not forget to send a
1455 after you have updated
1456 .Pa /etc/inetd.conf .
1457 Here, we use a label named
1460 .Pa /etc/ppp/ppp.conf
1461 on ui-gate (the receiver) should contain the following:
1462 .Bd -literal -offset indent
1465 set ifaddr 10.0.4.1 10.0.4.2
1469 .Pa /etc/ppp/ppp.linkup
1471 .Bd -literal -offset indent
1473 add 10.0.1.0/24 HISADDR
1476 It is necessary to put the
1480 to ensure that the route is only added after
1482 has negotiated and assigned addresses to its interface.
1484 You may also want to enable PAP or CHAP for security.
1485 To enable PAP, add the following line:
1486 .Bd -literal -offset indent
1490 You will also need to create the following entry in
1491 .Pa /etc/ppp/ppp.secret :
1492 .Bd -literal -offset indent
1493 MyAuthName MyAuthPasswd
1500 the password is looked up in the
1505 .Pa /etc/ppp/ppp.conf
1506 on awfulhak (the initiator) should contain the following:
1507 .Bd -literal -offset indent
1510 set device ui-gate:ppp-in/tcp
1513 set log Phase Chat Connect hdlc LCP IPCP IPV6CP CCP tun
1514 set ifaddr 10.0.4.2 10.0.4.1
1517 with the route setup in
1518 .Pa /etc/ppp/ppp.linkup :
1519 .Bd -literal -offset indent
1521 add 10.0.2.0/24 HISADDR
1524 Again, if you are enabling PAP, you will also need this in the
1525 .Pa /etc/ppp/ppp.conf
1527 .Bd -literal -offset indent
1528 set authname MyAuthName
1529 set authkey MyAuthKey
1532 We are assigning the address of 10.0.4.1 to ui-gate, and the address
1533 10.0.4.2 to awfulhak.
1534 To open the connection, just type
1536 .Dl awfulhak # ppp -background ui-gate
1538 The result will be an additional "route" on awfulhak to the
1539 10.0.2.0/24 network via the TCP connection, and an additional
1540 "route" on ui-gate to the 10.0.1.0/24 network.
1541 The networks are effectively bridged - the underlying TCP
1542 connection may be across a public network (such as the
1545 traffic is conceptually encapsulated
1546 (although not packet by packet) inside the TCP stream between
1549 The major disadvantage of this mechanism is that there are two
1550 "guaranteed delivery" mechanisms in place - the underlying TCP
1551 stream and whatever protocol is used over the
1553 link - probably TCP again.
1554 If packets are lost, both levels will
1555 get in each others way trying to negotiate sending of the missing
1558 To avoid this overhead, it is also possible to do all this using
1559 UDP instead of TCP as the transport by simply changing the protocol
1560 from "tcp" to "udp".
1561 When using UDP as a transport,
1563 will operate in synchronous mode.
1564 This is another gain as the incoming
1565 data does not have to be rearranged into packets.
1567 Care should be taken when adding a default route through a tunneled
1569 It is quite common for the default route
1571 .Pa /etc/ppp/ppp.linkup )
1572 to end up routing the link's TCP connection through the tunnel,
1573 effectively garrotting the connection.
1574 To avoid this, make sure you add a static route for the benefit of
1576 .Bd -literal -offset indent
1579 set device ui-gate:ppp-in/tcp
1586 is the IP number that your route to
1590 When routing your connection across a public network such as the Internet,
1591 it is preferable to encrypt the data.
1592 This can be done with the help of the MPPE protocol, although currently this
1593 means that you will not be able to also compress the traffic as MPPE is
1594 implemented as a compression layer (thank Microsoft for this).
1595 To enable MPPE encryption, add the following lines to
1596 .Pa /etc/ppp/ppp.conf
1598 .Bd -literal -offset indent
1600 disable deflate pred1
1604 ensuring that you have put the requisite entry in
1605 .Pa /etc/ppp/ppp.secret
1606 (MSCHAPv2 is challenge based, so
1610 MSCHAPv2 and MPPE are accepted by default, so the client end should work
1611 without any additional changes (although ensure you have
1616 .Sh NETWORK ADDRESS TRANSLATION (PACKET ALIASING)
1619 command line option enables network address translation (a.k.a.\& packet
1623 host to act as a masquerading gateway for other computers over
1624 a local area network.
1625 Outgoing IP packets are NAT'd so that they appear to come from the
1627 host, and incoming packets are de-NAT'd so that they are routed
1628 to the correct machine on the local area network.
1629 NAT allows computers on private, unregistered subnets to have Internet
1630 access, although they are invisible from the outside world.
1633 operation should first be verified with network address translation disabled.
1636 option should be switched on, and network applications (web browser,
1641 should be checked on the
1644 Finally, the same or similar applications should be checked on other
1645 computers in the LAN.
1646 If network applications work correctly on the
1648 host, but not on other machines in the LAN, then the masquerading
1649 software is working properly, but the host is either not forwarding
1650 or possibly receiving IP packets.
1651 Check that IP forwarding is enabled in
1653 and that other machines have designated the
1655 host as the gateway for the LAN.
1656 .Sh PACKET FILTERING
1657 This implementation supports packet filtering.
1658 There are four kinds of
1668 Here are the basics:
1671 A filter definition has the following syntax:
1680 .Ar src_addr Ns Op / Ns Ar width
1681 .Op Ar dst_addr Ns Op / Ns Ar width
1683 .Ar [ proto Op src Ar cmp port
1688 .Op timeout Ar secs ]
1700 is a numeric value between
1704 specifying the rule number.
1705 Rules are specified in numeric order according to
1716 in which case, if a given packet matches the rule, the associated action
1717 is taken immediately.
1719 can also be specified as
1721 to clear the action associated with that particular rule, or as a new
1722 rule number greater than the current rule.
1723 In this case, if a given
1724 packet matches the current rule, the packet will next be matched against
1725 the new rule number (rather than the next rule number).
1729 may optionally be followed with an exclamation mark
1733 to reverse the sense of the following match.
1735 .Op Ar src_addr Ns Op / Ns Ar width
1737 .Op Ar dst_addr Ns Op / Ns Ar width
1738 are the source and destination IP number specifications.
1741 is specified, it gives the number of relevant netmask bits,
1742 allowing the specification of an address range.
1748 may be given the values
1754 (refer to the description of the
1756 command for a description of these values).
1757 When these values are used,
1758 the filters will be updated any time the values change.
1759 This is similar to the behaviour of the
1764 may be any protocol from
1773 meaning less-than, equal and greater-than respectively.
1775 can be specified as a numeric port or by service name from
1783 flags are only allowed when
1787 and represent the TH_ACK, TH_SYN and TH_FIN or TH_RST TCP flags respectively.
1789 The timeout value adjusts the current idle timeout to at least
1792 If a timeout is given in the alive filter as well as in the in/out
1793 filter, the in/out value is used.
1794 If no timeout is given, the default timeout (set using
1796 and defaulting to 180 seconds) is used.
1799 Each filter can hold up to 40 rules, starting from rule 0.
1800 The entire rule set is not effective until rule 0 is defined,
1801 i.e., the default is to allow everything through.
1803 If no rule in a defined set of rules matches a packet, that packet will
1804 be discarded (blocked).
1805 If there are no rules in a given filter, the packet will be permitted.
1807 It is possible to filter based on the payload of UDP frames where those
1813 .Ar filter-decapsulation
1814 option below for further details.
1817 .Dq set filter Ar name No -1
1822 .Pa /usr/share/examples/ppp/ppp.conf.sample .
1823 .Sh SETTING THE IDLE TIMER
1824 To check/set the idle timer, use the
1829 .Bd -literal -offset indent
1830 ppp ON awfulhak> set timeout 600
1833 The timeout period is measured in seconds, the default value for which
1836 To disable the idle timer function, use the command
1837 .Bd -literal -offset indent
1838 ppp ON awfulhak> set timeout 0
1845 modes, the idle timeout is ignored.
1848 mode, when the idle timeout causes the
1853 program itself remains running.
1854 Another trigger packet will cause it to attempt to re-establish the link.
1855 .Sh PREDICTOR-1 and DEFLATE COMPRESSION
1857 supports both Predictor type 1 and deflate compression.
1860 will attempt to use (or be willing to accept) both compression protocols
1861 when the peer agrees
1863 The deflate protocol is preferred by
1869 commands if you wish to disable this functionality.
1871 It is possible to use a different compression algorithm in each direction
1872 by using only one of
1876 (assuming that the peer supports both algorithms).
1878 By default, when negotiating DEFLATE,
1880 will use a window size of 15.
1883 command if you wish to change this behaviour.
1885 A special algorithm called DEFLATE24 is also available, and is disabled
1886 and denied by default.
1887 This is exactly the same as DEFLATE except that
1888 it uses CCP ID 24 to negotiate.
1891 to successfully negotiate DEFLATE with
1894 .Sh CONTROLLING IP ADDRESS
1897 uses IPCP to negotiate IP addresses.
1898 Each side of the connection
1899 specifies the IP address that it is willing to use, and if the requested
1900 IP address is acceptable then
1902 returns an ACK to the requester.
1905 returns NAK to suggest that the peer use a different IP address.
1907 both sides of the connection agree to accept the received request (and
1908 send an ACK), IPCP is set to the open state and a network level connection
1910 To control this IPCP behaviour, this implementation has the
1912 command for defining the local and remote IP address:
1913 .Bd -ragged -offset indent
1914 .No set ifaddr Oo Ar src_addr Ns
1916 .Oo Ar dst_addr Ns Op / Ns Ar \&nn
1926 is the IP address that the local side is willing to use,
1928 is the IP address which the remote side should use and
1930 is the netmask that should be used.
1932 defaults to the current
1935 defaults to 0.0.0.0, and
1937 defaults to whatever mask is appropriate for
1939 It is only possible to make
1941 smaller than the default.
1942 The usual value is 255.255.255.255, as
1943 most kernels ignore the netmask of a POINTOPOINT interface.
1947 implementations require that the peer negotiates a specific IP
1950 If this is the case,
1952 may be used to specify this IP number.
1953 This will not affect the
1954 routing table unless the other side agrees with this proposed number.
1955 .Bd -literal -offset indent
1956 set ifaddr 192.244.177.38 192.244.177.2 255.255.255.255 0.0.0.0
1959 The above specification means:
1961 .Bl -bullet -compact
1963 I will first suggest that my IP address should be 0.0.0.0, but I
1964 will only accept an address of 192.244.177.38.
1966 I strongly insist that the peer uses 192.244.177.2 as his own
1967 address and will not permit the use of any IP address but 192.244.177.2.
1968 When the peer requests another IP address, I will always suggest that
1969 it uses 192.244.177.2.
1971 The routing table entry will have a netmask of 0xffffffff.
1974 This is all fine when each side has a pre-determined IP address, however
1975 it is often the case that one side is acting as a server which controls
1976 all IP addresses and the other side should go along with it.
1977 In order to allow more flexible behaviour, the
1979 command allows the user to specify IP addresses more loosely:
1981 .Dl set ifaddr 192.244.177.38/24 192.244.177.2/20
1983 A number followed by a slash
1985 represents the number of bits significant in the IP address.
1986 The above example means:
1988 .Bl -bullet -compact
1990 I would like to use 192.244.177.38 as my address if it is possible, but I will
1991 also accept any IP address between 192.244.177.0 and 192.244.177.255.
1993 I would like to make him use 192.244.177.2 as his own address, but I will also
1994 permit him to use any IP address between 192.244.176.0 and
1997 As you may have already noticed, 192.244.177.2 is equivalent to saying
2000 As an exception, 0 is equivalent to 0.0.0.0/0, meaning that I have no
2001 preferred IP address and will obey the remote peers selection.
2002 When using zero, no routing table entries will be made until a connection
2005 192.244.177.2/0 means that I will accept/permit any IP address but I will
2006 suggest that 192.244.177.2 be used first.
2009 When negotiating IPv6 addresses, no control is given to the user.
2010 IPV6CP negotiation is fully automatic.
2011 .Sh CONNECTING WITH YOUR INTERNET SERVICE PROVIDER
2012 The following steps should be taken when connecting to your ISP:
2015 Describe your providers phone number(s) in the dial script using the
2018 This command allows you to set multiple phone numbers for
2019 dialing and redialing separated by either a pipe
2023 .Bd -ragged -offset indent
2024 .No set phone Ar telno Ns
2025 .Oo \&| Ns Ar backupnumber Oc Ns ... Ns Oo : Ns Ar nextnumber Oc Ns ...
2028 Numbers after the first in a pipe-separated list are only used if the
2029 previous number was used in a failed dial or login script.
2031 separated by a colon are used sequentially, irrespective of what happened
2032 as a result of using the previous number.
2034 .Bd -literal -offset indent
2035 set phone "1234567|2345678:3456789|4567890"
2038 Here, the 1234567 number is attempted.
2039 If the dial or login script fails,
2040 the 2345678 number is used next time, but *only* if the dial or login script
2042 On the dial after this, the 3456789 number is used.
2044 number is only used if the dial or login script using the 3456789 fails.
2045 If the login script of the 2345678 number fails, the next number is still the
2047 As many pipes and colons can be used as are necessary
2048 (although a given site would usually prefer to use either the pipe or the
2049 colon, but not both).
2050 The next number redial timeout is used between all numbers.
2051 When the end of the list is reached, the normal redial period is
2052 used before starting at the beginning again.
2053 The selected phone number is substituted for the \\\\T string in the
2055 command (see below).
2057 Set up your redial requirements using
2059 For example, if you have a bad telephone line or your provider is
2060 usually engaged (not so common these days), you may want to specify
2062 .Bd -literal -offset indent
2066 This says that up to 4 phone calls should be attempted with a pause of 10
2067 seconds before dialing the first number again.
2069 Describe your login procedure using the
2076 command is used to talk to your modem and establish a link with your
2078 .Bd -literal -offset indent
2079 set dial "ABORT BUSY ABORT NO\\\\sCARRIER TIMEOUT 4 \\"\\" \e
2080 ATZ OK-ATZ-OK ATDT\\\\T TIMEOUT 60 CONNECT"
2083 This modem "chat" string means:
2086 Abort if the string "BUSY" or "NO CARRIER" are received.
2088 Set the timeout to 4 seconds.
2095 If that is not received within the 4 second timeout, send ATZ
2098 Send ATDTxxxxxxx where xxxxxxx is the next number in the phone list from
2101 Set the timeout to 60.
2103 Wait for the CONNECT string.
2106 Once the connection is established, the login script is executed.
2107 This script is written in the same style as the dial script, but care should
2108 be taken to avoid having your password logged:
2109 .Bd -literal -offset indent
2110 set authkey MySecret
2111 set login "TIMEOUT 15 login:-\\\\r-login: awfulhak \e
2112 word: \\\\P ocol: PPP HELLO"
2115 This login "chat" string means:
2118 Set the timeout to 15 seconds.
2121 If it is not received, send a carriage return and expect
2126 Expect "word:" (the tail end of a "Password:" prompt).
2128 Send whatever our current
2132 Expect "ocol:" (the tail end of a "Protocol:" prompt).
2141 command is logged specially.
2146 logging is enabled, the actual password is not logged;
2150 Login scripts vary greatly between ISPs.
2151 If you are setting one up for the first time,
2152 .Em ENABLE CHAT LOGGING
2153 so that you can see if your script is behaving as you expect.
2159 to specify your serial line and speed, for example:
2160 .Bd -literal -offset indent
2161 set device /dev/cuau0
2165 Cuad0 is the first serial port on
2172 A speed of 115200 should be specified
2173 if you have a modem capable of bit rates of 28800 or more.
2174 In general, the serial speed should be about four times the modem speed.
2178 command to {define} the IP address.
2181 If you know what IP address your provider uses, then use it as the remote
2182 address (dst_addr), otherwise choose something like 10.0.0.2/0 (see below).
2184 If your provider has assigned a particular IP address to you, then use
2185 it as your address (src_addr).
2187 If your provider assigns your address dynamically, choose a suitably
2188 unobtrusive and unspecific IP number as your address.
2189 10.0.0.1/0 would be appropriate.
2190 The bit after the / specifies how many bits of the
2191 address you consider to be important, so if you wanted to insist on
2192 something in the class C network 1.2.3.0, you could specify 1.2.3.1/24.
2194 If you find that your ISP accepts the first IP number that you suggest,
2195 specify third and forth arguments of
2197 This will force your ISP to assign a number.
2198 (The third argument will
2199 be ignored as it is less restrictive than the default mask for your
2203 An example for a connection where you do not know your IP number or your
2204 ISPs IP number would be:
2205 .Bd -literal -offset indent
2206 set ifaddr 10.0.0.1/0 10.0.0.2/0 0.0.0.0 0.0.0.0
2209 In most cases, your ISP will also be your default router.
2210 If this is the case, add the line
2211 .Bd -literal -offset indent
2216 .Pa /etc/ppp/ppp.conf
2218 .Pa /etc/ppp/ppp.linkup
2219 for setups that do not use
2225 to add a default route to whatever the peer address is
2226 (10.0.0.2 in this example).
2229 meaning that should the value of
2231 change, the route will be updated accordingly.
2233 If your provider requests that you use PAP/CHAP authentication methods, add
2234 the next lines to your
2235 .Pa /etc/ppp/ppp.conf
2237 .Bd -literal -offset indent
2239 set authkey MyPassword
2242 Both are accepted by default, so
2244 will provide whatever your ISP requires.
2246 It should be noted that a login script is rarely (if ever) required
2247 when PAP or CHAP are in use.
2249 Ask your ISP to authenticate your nameserver address(es) with the line
2250 .Bd -literal -offset indent
2256 do this if you are running a local DNS unless you also either use
2261 .Pa /etc/ppp/ppp.linkdown ,
2264 will simply circumvent its use by entering some nameserver lines in
2265 .Pa /etc/resolv.conf .
2269 .Pa /usr/share/examples/ppp/ppp.conf.sample
2271 .Pa /usr/share/examples/ppp/ppp.linkup.sample
2272 for some real examples.
2273 The pmdemand label should be appropriate for most ISPs.
2274 .Sh LOGGING FACILITY
2276 is able to generate the following log info either via
2278 or directly to the screen:
2280 .Bl -tag -width XXXXXXXXX -offset XXX -compact
2282 Enable all logging facilities.
2283 This generates a lot of log.
2284 The most common use of 'all' is as a basis, where you remove some facilities
2285 after enabling 'all' ('debug' and 'timer' are usually best disabled.)
2287 Dump async level packet in hex.
2289 Generate CBCP (CallBack Control Protocol) logs.
2291 Generate a CCP packet trace.
2299 chat script trace logs.
2301 Log commands executed either from the command line or any of the configuration
2304 Log Chat lines containing the string "CONNECT".
2306 Log debug information.
2308 Log DNS QUERY packets.
2310 Log packets permitted by the dial filter and denied by any filter.
2312 Dump HDLC packet in hex.
2314 Log all function calls specifically made as user id 0.
2316 Generate an IPCP packet trace.
2318 Generate an LCP packet trace.
2320 Generate LQR reports.
2322 Phase transition log output.
2324 Dump physical level packet in hex.
2326 Dump RADIUS information.
2327 RADIUS information resulting from the link coming up or down is logged at
2332 This log level is most useful for monitoring RADIUS alive information.
2334 Dump sync level packet in hex.
2336 Dump all TCP/IP packets.
2338 Log timer manipulation.
2340 Include the tun device on each log line.
2342 Output to the terminal device.
2343 If there is currently no terminal,
2344 output is sent to the log file using syslogs
2347 Output to both the terminal device
2348 and the log file using syslogs
2351 Output to the log file using
2357 command allows you to set the logging output level.
2358 Multiple levels can be specified on a single command line.
2359 The default is equivalent to
2362 It is also possible to log directly to the screen.
2363 The syntax is the same except that the word
2365 should immediately follow
2369 (i.e., only the un-maskable warning, error and alert output).
2371 If The first argument to
2372 .Dq set log Op local
2377 character, the current log levels are
2378 not cleared, for example:
2379 .Bd -literal -offset indent
2380 PPP ON awfulhak> set log phase
2381 PPP ON awfulhak> show log
2382 Log: Phase Warning Error Alert
2383 Local: Warning Error Alert
2384 PPP ON awfulhak> set log +tcp/ip -warning
2385 PPP ON awfulhak> set log local +command
2386 PPP ON awfulhak> show log
2387 Log: Phase TCP/IP Warning Error Alert
2388 Local: Command Warning Error Alert
2391 Log messages of level Warning, Error and Alert are not controllable
2393 .Dq set log Op local .
2397 level is special in that it will not be logged if it can be displayed
2401 deals with the following signals:
2402 .Bl -tag -width "USR2"
2404 Receipt of this signal causes the termination of the current connection
2408 to exit unless it is in
2413 .It HUP, TERM & QUIT
2420 to re-open any existing server socket, dropping all existing diagnostic
2422 Sockets that could not previously be opened will be retried.
2426 to close any existing server socket, dropping all existing diagnostic
2429 can still be used to re-open the socket.
2432 If you wish to use more than one physical link to connect to a
2434 peer, that peer must also understand the
2437 Refer to RFC 1990 for specification details.
2439 The peer is identified using a combination of his
2440 .Dq endpoint discriminator
2442 .Dq authentication id .
2443 Either or both of these may be specified.
2444 It is recommended that
2445 at least one is specified, otherwise there is no way of ensuring that
2446 all links are actually connected to the same peer program, and some
2447 confusing lock-ups may result.
2448 Locally, these identification variables are specified using the
2457 must be agreed in advance with the peer.
2459 Multi-link capabilities are enabled using the
2461 command (set maximum reconstructed receive unit).
2462 Once multi-link is enabled,
2464 will attempt to negotiate a multi-link connection with the peer.
2466 By default, only one
2471 To create more links, the
2474 This command will clone existing links, where all
2475 characteristics are the same except:
2478 The new link has its own name as specified on the
2485 Its mode may subsequently be changed using the
2489 The new link is in a
2494 A summary of all available links can be seen using the
2498 Once a new link has been created, command usage varies.
2499 All link specific commands must be prefixed with the
2501 command, specifying on which link the command is to be applied.
2502 When only a single link is available,
2504 is smart enough not to require the
2508 Some commands can still be used without specifying a link - resulting
2509 in an operation at the
2512 For example, once two or more links are available, the command
2514 will show CCP configuration and statistics at the multi-link level, and
2515 .Dq link deflink show ccp
2516 will show the same information at the
2520 Armed with this information, the following configuration might be used:
2521 .Bd -literal -offset indent
2525 set device /dev/cuau0 /dev/cuau1 /dev/cuau2
2526 set phone "123456789"
2527 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \\"\\" ATZ \e
2528 OK-AT-OK \\\\dATDT\\\\T TIMEOUT 45 CONNECT"
2530 set ifaddr 10.0.0.1/0 10.0.0.2/0 0.0.0.0 0.0.0.0
2532 set authkey ppppassword
2535 clone 1,2,3 # Create 3 new links - duplicates of the default
2536 link deflink remove # Delete the default link (called ``deflink'')
2539 Note how all cloning is done at the end of the configuration.
2540 Usually, the link will be configured first, then cloned.
2541 If you wish all links
2542 to be up all the time, you can add the following line to the end of your
2544 .Bd -literal -offset indent
2545 link 1,2,3 set mode ddial
2548 If you want the links to dial on demand, this command could be used:
2549 .Bd -literal -offset indent
2550 link * set mode auto
2553 Links may be tied to specific names by removing the
2555 line above, and specifying the following after the
2558 .Bd -literal -offset indent
2559 link 1 set device /dev/cuau0
2560 link 2 set device /dev/cuau1
2561 link 3 set device /dev/cuau2
2566 command to see which commands require context (using the
2568 command), which have optional
2569 context and which should not have any context.
2575 mode with the peer, it creates a local domain socket in the
2578 This socket is used to pass link information (including
2579 the actual link file descriptor) between different
2584 ability to be run from a
2590 capability), without needing to have initial control of the serial
2594 negotiates multi-link mode, it will pass its open link to any
2595 already running process.
2596 If there is no already running process,
2598 will act as the master, creating the socket and listening for new
2600 .Sh PPP COMMAND LIST
2601 This section lists the available commands and their effect.
2602 They are usable either from an interactive
2604 session, from a configuration file or from a
2610 .It accept|deny|enable|disable Ar option....
2611 These directives tell
2613 how to negotiate the initial connection with the peer.
2616 has a default of either accept or deny and enable or disable.
2618 means that the option will be ACK'd if the peer asks for it.
2620 means that the option will be NAK'd if the peer asks for it.
2622 means that the option will be requested by us.
2624 means that the option will not be requested by us.
2627 may be one of the following:
2630 Default: Enabled and Accepted.
2631 ACFComp stands for Address and Control Field Compression.
2632 Non LCP packets will usually have an address
2633 field of 0xff (the All-Stations address) and a control field of
2634 0x03 (the Unnumbered Information command).
2636 negotiated, these two bytes are simply not sent, thus minimising
2643 Default: Disabled and Accepted.
2644 CHAP stands for Challenge Handshake Authentication Protocol.
2645 Only one of CHAP and PAP (below) may be negotiated.
2646 With CHAP, the authenticator sends a "challenge" message to its peer.
2647 The peer uses a one-way hash function to encrypt the
2648 challenge and sends the result back.
2649 The authenticator does the same, and compares the results.
2650 The advantage of this mechanism is that no
2651 passwords are sent across the connection.
2652 A challenge is made when the connection is first made.
2653 Subsequent challenges may occur.
2654 If you want to have your peer authenticate itself, you must
2657 .Pa /etc/ppp/ppp.conf ,
2658 and have an entry in
2659 .Pa /etc/ppp/ppp.secret
2662 When using CHAP as the client, you need only specify
2667 .Pa /etc/ppp/ppp.conf .
2668 CHAP is accepted by default.
2671 implementations use "MS-CHAP" rather than MD5 when encrypting the
2673 MS-CHAP is a combination of MD4 and DES.
2676 was built on a machine with DES libraries available, it will respond
2677 to MS-CHAP authentication requests, but will never request them.
2679 Default: Enabled and Accepted.
2680 This option decides if deflate
2681 compression will be used by the Compression Control Protocol (CCP).
2682 This is the same algorithm as used by the
2685 Note: There is a problem negotiating
2691 implementation available under many operating systems.
2693 (version 2.3.1) incorrectly attempts to negotiate
2695 compression using type
2697 as the CCP configuration type rather than type
2703 is actually specified as
2704 .Dq PPP Magna-link Variable Resource Compression
2708 is capable of negotiating with
2715 .Ar accept Ns No ed .
2717 Default: Disabled and Denied.
2718 This is a variance of the
2720 option, allowing negotiation with the
2725 section above for details.
2726 It is disabled by default as it violates
2729 Default: Disabled and Denied.
2730 This option allows DNS negotiation.
2735 will request that the peer confirms the entries in
2736 .Pa /etc/resolv.conf .
2737 If the peer NAKs our request (suggesting new IP numbers),
2738 .Pa /etc/resolv.conf
2739 is updated and another request is sent to confirm the new entries.
2742 .Dq accept Ns No ed,
2744 will answer any DNS queries requested by the peer rather than rejecting
2746 The answer is taken from
2747 .Pa /etc/resolv.conf
2750 command is used as an override.
2752 Default: Enabled and Accepted.
2753 This option allows control over whether we
2754 negotiate an endpoint discriminator.
2755 We only send our discriminator if
2760 We reject the peers discriminator if
2764 Default: Disabled and Accepted.
2765 The use of this authentication protocol
2766 is discouraged as it partially violates the authentication protocol by
2767 implementing two different mechanisms (LANMan & NT) under the guise of
2768 a single CHAP type (0x80).
2770 uses a simple DES encryption mechanism and is the least secure of the
2771 CHAP alternatives (although is still more secure than PAP).
2775 description below for more details.
2777 Default: Disabled and Accepted.
2778 This option decides if Link Quality Requests will be sent or accepted.
2779 LQR is a protocol that allows
2781 to determine that the link is down without relying on the modems
2783 When LQR is enabled,
2789 below) as part of the LCP request.
2790 If the peer agrees, both sides will
2791 exchange LQR packets at the agreed frequency, allowing detailed link
2792 quality monitoring by enabling LQM logging.
2793 If the peer does not agree, and if the
2800 These packets pass no information of interest, but they
2802 be replied to by the peer.
2809 will abruptly drop the connection if 5 unacknowledged packets have been
2810 sent rather than sending a 6th.
2811 A message is logged at the
2813 level, and any appropriate
2815 values are honoured as if the peer were responsible for dropping the
2820 command description for differences in behaviour prior to
2824 Default: Enabled and Accepted.
2825 This is Microsoft Point to Point Encryption scheme.
2826 MPPE key size can be
2827 40-, 56- and 128-bits.
2832 Default: Disabled and Accepted.
2833 It is very similar to standard CHAP (type 0x05)
2834 except that it issues challenges of a fixed 16 bytes in length and uses a
2835 combination of MD4, SHA-1 and DES to encrypt the challenge rather than using the
2836 standard MD5 mechanism.
2838 Default: Disabled and Accepted.
2839 The use of this authentication protocol
2840 is discouraged as it partially violates the authentication protocol by
2841 implementing two different mechanisms (LANMan & NT) under the guise of
2842 a single CHAP type (0x80).
2843 It is very similar to standard CHAP (type 0x05)
2844 except that it issues challenges of a fixed 8 bytes in length and uses a
2845 combination of MD4 and DES to encrypt the challenge rather than using the
2846 standard MD5 mechanism.
2847 CHAP type 0x80 for LANMan is also supported - see
2855 use CHAP type 0x80, when acting as authenticator with both
2856 .Dq enable Ns No d ,
2858 will rechallenge the peer up to three times if it responds using the wrong
2859 one of the two protocols.
2860 This gives the peer a chance to attempt using both protocols.
2864 acts as the authenticatee with both protocols
2865 .Dq accept Ns No ed ,
2866 the protocols are used alternately in response to challenges.
2868 Note: If only LANMan is enabled,
2870 (version 2.3.5) misbehaves when acting as authenticatee.
2872 the NT and the LANMan answers, but also suggests that only the NT answer
2875 Default: Disabled and Accepted.
2876 PAP stands for Password Authentication Protocol.
2877 Only one of PAP and CHAP (above) may be negotiated.
2878 With PAP, the ID and Password are sent repeatedly to the peer until
2879 authentication is acknowledged or the connection is terminated.
2880 This is a rather poor security mechanism.
2881 It is only performed when the connection is first established.
2882 If you want to have your peer authenticate itself, you must
2885 .Pa /etc/ppp/ppp.conf ,
2886 and have an entry in
2887 .Pa /etc/ppp/ppp.secret
2888 for the peer (although see the
2894 When using PAP as the client, you need only specify
2899 .Pa /etc/ppp/ppp.conf .
2900 PAP is accepted by default.
2902 Default: Enabled and Accepted.
2903 This option decides if Predictor 1
2904 compression will be used by the Compression Control Protocol (CCP).
2906 Default: Enabled and Accepted.
2907 This option is used to negotiate
2908 PFC (Protocol Field Compression), a mechanism where the protocol
2909 field number is reduced to one octet rather than two.
2911 Default: Enabled and Accepted.
2912 This option determines if
2914 will request and accept requests for short
2916 sequence numbers when negotiating multi-link mode.
2917 This is only applicable if our MRRU is set (thus enabling multi-link).
2919 Default: Enabled and Accepted.
2920 This option determines if Van Jacobson header compression will be used.
2923 The following options are not actually negotiated with the peer.
2924 Therefore, accepting or denying them makes no sense.
2928 When this option is enabled,
2932 requests to the peer at the frequency defined by
2936 requests will supersede
2938 requests if enabled and negotiated.
2947 was considered enabled if lqr was enabled and negotiated, otherwise it was
2948 considered disabled.
2949 For the same behaviour, it is now necessary to
2953 .It filter-decapsulation
2955 When this option is enabled,
2957 will examine UDP frames to see if they actually contain a
2959 frame as their payload.
2960 If this is the case, all filters will operate on the payload rather
2961 than the actual packet.
2963 This is useful if you want to send PPPoUDP traffic over a
2965 link, but want that link to do smart things with the real data rather than
2968 The UDP frame payload must not be compressed in any way, otherwise
2970 will not be able to interpret it.
2971 It is therefore recommended that you
2972 .Ic disable vj pred1 deflate
2974 .Ic deny vj pred1 deflate
2975 in the configuration for the
2977 invocation with the udp link.
2980 Forces execution of the configured chat scripts in
2989 exchanges low-level LCP, CCP and IPCP configuration traffic, the
2991 field of any replies is expected to be the same as that of the request.
2994 drops any reply packets that do not contain the expected identifier
2995 field, reporting the fact at the respective log level.
3000 will ignore the identifier field.
3005 This option simply tells
3007 to add new interface addresses to the interface rather than replacing them.
3008 The option can only be enabled if network address translation is enabled
3009 .Pq Dq nat enable yes .
3011 With this option enabled,
3013 will pass traffic for old interface addresses through the NAT
3017 resulting in the ability (in
3019 mode) to properly connect the process that caused the PPP link to
3020 come up in the first place.
3030 to attempt to negotiate IP control protocol capabilities and if
3031 successful to exchange IP datagrams with the peer.
3036 to attempt to negotiate IPv6 control protocol capabilities and if
3037 successful to exchange IPv6 datagrams with the peer.
3042 runs as a Multi-link server, a different
3044 instance initially receives each connection.
3045 After determining that
3046 the link belongs to an already existing bundle (controlled by another
3050 will transfer the link to that process.
3052 If the link is a tty device or if this option is enabled,
3054 will not exit, but will change its process name to
3056 and wait for the controlling
3058 to finish with the link and deliver a signal back to the idle process.
3059 This prevents the confusion that results from
3061 parent considering the link resource available again.
3063 For tty devices that have entries in
3065 this is necessary to prevent another
3067 from being started, and for program links such as
3071 from exiting due to the death of its child.
3074 cannot determine its parents requirements (except for the tty case), this
3075 option must be enabled manually depending on the circumstances.
3082 will automatically loop back packets being sent
3083 out with a destination address equal to that of the
3088 will send the packet, probably resulting in an ICMP redirect from
3090 It is convenient to have this option enabled when
3091 the interface is also the default route as it avoids the necessity
3092 of a loopback route.
3095 This option controls whether
3099 attribute to the RADIUS server when RADIUS is in use
3100 .Pq see Dq set radius .
3102 Note, at least one of
3110 prior to version 3.4.1 did not send the
3112 attribute as it was reported to break the Radiator RADIUS server.
3113 As the latest rfc (2865) no longer hints that only one of
3117 should be sent (as rfc 2138 did),
3119 now sends both and leaves it up to the administrator that chooses to use
3120 bad RADIUS implementations to
3121 .Dq disable NAS-IP-Address .
3124 This option controls whether
3128 attribute to the RADIUS server when RADIUS is in use
3129 .Pq see Dq set radius .
3131 Note, at least one of
3138 Enabling this option will tell the PAP authentication
3139 code to use the password database (see
3141 to authenticate the caller if they cannot be found in the
3142 .Pa /etc/ppp/ppp.secret
3144 .Pa /etc/ppp/ppp.secret
3145 is always checked first.
3146 If you wish to use passwords from
3148 but also to specify an IP number or label for a given client, use
3150 as the client password in
3151 .Pa /etc/ppp/ppp.secret .
3154 Enabling this option will tell
3156 to proxy ARP for the peer.
3159 will make an entry in the ARP table using
3163 address of the local network in which
3166 This allows other machines connecteed to the LAN to talk to
3167 the peer as if the peer itself was connected to the LAN.
3168 The proxy entry cannot be made unless
3170 is an address from a LAN.
3173 Enabling this will tell
3175 to add proxy arp entries for every IP address in all class C or
3176 smaller subnets routed via the tun interface.
3178 Proxy arp entries are only made for sticky routes that are added
3182 No proxy arp entries are made for the interface address itself
3190 command is used with the
3196 values, entries are stored in the
3199 Each time these variables change, this list is re-applied to the routing table.
3201 Disabling this option will prevent the re-application of sticky routes,
3204 list will still be maintained.
3205 .It Oo tcp Oc Ns No mssfixup
3209 to adjust TCP SYN packets so that the maximum receive segment
3210 size is not greater than the amount allowed by the interface MTU.
3215 to gather throughput statistics.
3216 Input and output is sampled over
3217 a rolling 5 second window, and current, best and total figures are retained.
3218 This data is output when the relevant
3220 layer shuts down, and is also available using the
3223 Throughput statistics are available at the
3230 Normally, when a user is authenticated using PAP or CHAP, and when
3234 mode, an entry is made in the utmp and wtmp files for that user.
3235 Disabling this option will tell
3237 not to make any utmp or wtmp entries.
3238 This is usually only necessary if
3239 you require the user to both login and authenticate themselves.
3243 .Ar dest Ns Op / Ns Ar nn
3248 is the destination IP address.
3249 The netmask is specified either as a number of bits with
3251 or as an IP number using
3256 with no mask refers to the default route.
3257 It is also possible to use the literal name
3262 is the next hop gateway to get to the given
3267 command for further details.
3269 It is possible to use the symbolic names
3275 as the destination, and
3282 is replaced with the interface IP address,
3284 is replaced with the interface IP destination (peer) address,
3286 is replaced with the interface IPv6 address, and
3288 is replaced with the interface IPv6 destination address,
3295 then if the route already exists, it will be updated as with the
3299 for further details).
3301 Routes that contain the
3309 constants are considered
3311 They are stored in a list (use
3313 to see the list), and each time the value of one of these variables
3314 changes, the appropriate routing table entries are updated.
3315 This facility may be disabled using
3316 .Dq disable sroutes .
3317 .It allow Ar command Op Ar args
3318 This command controls access to
3320 and its configuration files.
3321 It is possible to allow user-level access,
3322 depending on the configuration file label and on the mode that
3325 For example, you may wish to configure
3335 User id 0 is immune to these commands.
3337 .It allow user Ns Xo
3339 .Ar logname Ns No ...
3341 By default, only user id 0 is allowed access to
3343 If this command is used, all of the listed users are allowed access to
3344 the section in which the
3349 section is always checked first (even though it is only ever automatically
3352 commands are cumulative in a given section, but users allowed in any given
3353 section override users allowed in the default section, so it is possible to
3354 allow users access to everything except a given label by specifying default
3357 section, and then specifying a new user list for that label.
3361 is specified, access is allowed to all users.
3362 .It allow mode Ns Xo
3366 By default, access using any
3369 If this command is used, it restricts the access
3371 allowed to load the label under which this command is specified.
3376 command overrides any previous settings, and the
3378 section is always checked first.
3390 When running in multi-link mode, a section can be loaded if it allows
3392 of the currently existing line modes.
3394 .It nat Ar command Op Ar args
3395 This command allows the control of the network address translation (also
3396 known as masquerading or IP aliasing) facilities that are built into
3398 NAT is done on the external interface only, and is unlikely to make sense
3403 If nat is enabled on your system (it may be omitted at compile time),
3404 the following commands are possible:
3406 .It nat enable yes|no
3407 This command either switches network address translation on or turns it off.
3410 command line flag is synonymous with
3411 .Dq nat enable yes .
3412 .It nat addr Op Ar addr_local addr_alias
3413 This command allows data for
3417 It is useful if you own a small number of real IP numbers that
3418 you wish to map to specific machines behind your gateway.
3419 .It nat deny_incoming yes|no
3420 If set to yes, this command will refuse all incoming packets where an
3421 aliasing link does not already exist.
3423 .Sx CONCEPTUAL BACKGROUND
3426 for a description of what an
3430 It should be noted under what circumstances an aliasing link is
3433 It may be necessary to further protect your network from outside
3434 connections using the
3440 This command gives a summary of available nat commands.
3442 This option causes various NAT statistics and information to
3443 be logged to the file
3444 .Pa /var/log/alias.log .
3445 .It nat port Ar proto Ar targetIP Ns Xo
3446 .No : Ns Ar targetPort Ns
3448 .No - Ns Ar targetPort
3451 .No - Ns Ar aliasPort
3452 .Oc Oo Ar remoteIP : Ns
3455 .No - Ns Ar remotePort
3459 This command causes incoming
3473 A range of port numbers may be specified as shown above.
3474 The ranges must be of the same size.
3478 is specified, only data coming from that IP number is redirected.
3482 (indicating any source port)
3483 or a range of ports the same size as the other ranges.
3485 This option is useful if you wish to run things like Internet phone on
3486 machines behind your gateway, but is limited in that connections to only
3487 one interior machine per source machine and target port are possible.
3488 .It nat proto Ar proto localIP Oo
3489 .Ar publicIP Op Ar remoteIP
3493 to redirect packets of protocol type
3497 to the internal address
3502 is specified, only packets destined for that address are matched,
3503 otherwise the default alias address is used.
3507 is specified, only packets matching that source address are matched,
3509 This command is useful for redirecting tunnel endpoints to an internal machine,
3512 .Dl nat proto ipencap 10.0.0.1
3513 .It "nat proxy cmd" Ar arg Ns No ...
3516 to proxy certain connections, redirecting them to a given server.
3517 Refer to the description of
3518 .Fn PacketAliasProxyRule
3521 for details of the available commands.
3522 .It nat punch_fw Op Ar base count
3525 to punch holes in the firewall for FTP or IRC DCC connections.
3526 This is done dynamically by installing temporary firewall rules which
3527 allow a particular connection (and only that connection) to go through
3529 The rules are removed once the corresponding connection terminates.
3533 rules starting from rule number
3535 will be used for punching firewall holes.
3536 The range will be cleared when the
3540 If no arguments are given, firewall punching is disabled.
3541 .It nat skinny_port Op Ar port
3544 which TCP port is used by the Skinny Station protocol.
3546 Cisco IP phones to communicate with Cisco Call Managers to setup voice
3548 The typical port used by Skinny is 2000.
3550 If no argument is given, skinny aliasing is disabled.
3551 .It nat same_ports yes|no
3552 When enabled, this command will tell the network address translation engine to
3553 attempt to avoid changing the port number on outgoing packets.
3555 if you want to support protocols such as RPC and LPD which require
3556 connections to come from a well known port.
3557 .It nat target Op Ar address
3558 Set the given target address or clear it if no address is given.
3559 The target address is used by libalias to specify how to NAT incoming packets
3561 If a target address is not set or if
3563 is given, packets are not altered and are allowed to route to the internal
3566 The target address may be set to
3568 in which case libalias will redirect all packets to the interface address.
3569 .It nat use_sockets yes|no
3570 When enabled, this option tells the network address translation engine to
3571 create a socket so that it can guarantee a correct incoming ftp data or
3573 .It nat unregistered_only yes|no
3574 Only alter outgoing packets with an unregistered source address.
3575 According to RFC 1918, unregistered source addresses
3576 are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16.
3579 These commands are also discussed in the file
3581 which comes with the source distribution.
3587 is executed in the background with the following words replaced:
3588 .Bl -tag -width COMPILATIONDATE
3590 This is replaced with the local
3596 .It Li COMPILATIONDATE
3597 In previous software revisions, this was replaced with the date on which
3600 This is no longer supported as it breaks the ability to recompile the same
3601 code to produce an exact duplicate of a previous compilation.
3603 These are replaced with the primary and secondary nameserver IP numbers.
3604 If nameservers are negotiated by IPCP, the values of these macros will change.
3606 This is replaced with the local endpoint discriminator value.
3611 This is replaced with the peers IP number.
3613 This is replaced with the peers IPv6 number.
3615 This is replaced with the name of the interface that is in use.
3617 This is replaced with the number of IP bytes received since the connection
3620 This is replaced with the number of IP bytes sent since the connection
3623 This is replaced with the number of IP packets received since the connection
3626 This is replaced with the number of IP packets sent since the connection
3629 This is replaced with the number of IPv6 bytes received since the connection
3631 .It Li IPV6OCTETSOUT
3632 This is replaced with the number of IPv6 bytes sent since the connection
3634 .It Li IPV6PACKETSIN
3635 This is replaced with the number of IPv6 packets received since the connection
3637 .It Li IPV6PACKETSOUT
3638 This is replaced with the number of IPv6 packets sent since the connection
3641 This is replaced with the last label name used.
3642 A label may be specified on the
3644 command line, via the
3652 This is replaced with the IP number assigned to the local interface.
3654 This is replaced with the IPv6 number assigned to the local interface.
3656 This is replaced with the number of bytes received since the connection
3659 This is replaced with the number of bytes sent since the connection
3662 This is replaced with the number of packets received since the connection
3665 This is replaced with the number of packets sent since the connection
3668 This is replaced with the value of the peers endpoint discriminator.
3670 This is replaced with the current process id.
3672 This is replaced with the name of the diagnostic socket.
3674 This is replaced with the bundle uptime in HH:MM:SS format.
3676 This is replaced with the username that has been authenticated with PAP or
3678 Normally, this variable is assigned only in -direct mode.
3679 This value is available irrespective of whether utmp logging is enabled.
3681 This is replaced with the current version number of
3685 These substitutions are also done by the
3692 If you wish to pause
3694 while the command executes, use the
3697 .It clear physical|ipcp|ipv6 Op current|overall|peak...
3698 Clear the specified throughput values at either the
3706 is specified, context must be given (see the
3709 If no second argument is given, all values are cleared.
3710 .It clone Ar name Ns Xo
3711 .Op \&, Ns Ar name Ns
3714 Clone the specified link, creating one or more new links according to the
3717 This command must be used from the
3719 command below unless you have only got a single link (in which case that
3720 link becomes the default).
3721 Links may be removed using the
3725 The default link name is
3727 .It close Op lcp|ccp Ns Op !\&
3728 If no arguments are given, the relevant protocol layers will be brought
3729 down and the link will be closed.
3732 is specified, the LCP layer is brought down, but
3734 will not bring the link offline.
3735 It is subsequently possible to use
3738 to talk to the peer machine if, for example, something like
3743 is specified, only the relevant compression layer is closed.
3746 is used, the compression layer will remain in the closed state, otherwise
3747 it will re-enter the STOPPED state, waiting for the peer to initiate
3748 further CCP negotiation.
3749 In any event, this command does not disconnect the user from
3760 This command deletes the route with the given
3767 all non-direct entries in the routing table for the current interface,
3770 entries are deleted.
3775 the default route is deleted.
3783 will not complain if the route does not already exist.
3784 .It dial|call Oo Ar label Oc Ns Xo
3787 This command is the equivalent of
3791 and is provided for backwards compatibility.
3792 .It down Op Ar lcp|ccp
3793 Bring the relevant layer down ungracefully, as if the underlying layer
3794 had become unavailable.
3795 It is not considered polite to use this command on
3796 a Finite State Machine that is in the OPEN state.
3798 supplied, the entire link is closed (or if no context is given, all links
3804 layer is terminated but the device is not brought offline and the link
3808 is specified, only the relevant compression layer(s) are terminated.
3809 .It help|? Op Ar command
3810 Show a list of available commands.
3813 is specified, show the usage string for that command.
3814 .It ident Op Ar text Ns No ...
3815 Identify the link to the peer using
3819 is empty, link identification is disabled.
3820 It is possible to use any of the words described for the
3825 command for details of when
3827 identifies itself to the peer.
3828 .It iface Ar command Op args
3829 This command is used to control the interface used by
3832 may be one of the following:
3836 .Ar addr Ns Op / Ns Ar bits
3847 combination to the interface.
3848 Instead of specifying
3852 (with no space between it and
3854 If the given address already exists, the command fails unless the
3856 is used - in which case the previous interface address entry is overwritten
3857 with the new one, allowing a change of netmask or peer address.
3868 .Dq 255.255.255.255 .
3869 This address (the broadcast address) is the only duplicate peer address that
3872 .It iface clear Op INET | INET6
3873 If this command is used while
3875 is in the OPENED state or while in
3877 mode, all addresses except for the NCP negotiated address are deleted
3881 is not in the OPENED state and is not in
3883 mode, all interface addresses are deleted.
3885 If the INET or INET6 arguments are used, only addresses for that address
3887 .It iface delete Ns Xo
3892 This command deletes the given
3897 is used, no error is given if the address is not currently assigned to
3898 the interface (and no deletion takes place).
3899 .It iface name Ar name
3900 Renames the interface to
3902 .It iface description Ar description
3903 Sets the interface description to
3905 Useful if you have many interfaces on your system.
3907 Shows the current state and current addresses for the interface.
3908 It is much the same as running
3909 .Dq ifconfig INTERFACE .
3910 .It iface help Op Ar sub-command
3911 This command, when invoked without
3913 will show a list of possible
3915 sub-commands and a brief synopsis for each.
3918 only the synopsis for the given sub-command is shown.
3920 .It Oo data Oc Ns Xo
3922 .Ar name Ns Oo , Ns Ar name Oc Ns ... Ar command Op Ar args
3924 This command may prefix any other command if the user wishes to
3925 specify which link the command should affect.
3926 This is only applicable after multiple links have been created in Multi-link
3932 specifies the name of an existing link.
3935 is a comma separated list,
3937 is executed on each link.
3943 is executed on all links.
3944 .It load Oo Ar label Oc Ns Xo
3967 will not attempt to make an immediate connection.
3968 .It log Ar word Ns No ...
3969 Send the given word(s) to the log file with the prefix
3971 Word substitutions are done as explained under the
3974 .It open Op lcp|ccp|ipcp
3975 This is the opposite of the
3978 All closed links are immediately brought up apart from second and subsequent
3980 links - these will come up based on the
3982 command that has been used.
3986 argument is used while the LCP layer is already open, LCP will be
3988 This allows various LCP options to be changed, after which
3990 can be used to put them into effect.
3991 After renegotiating LCP,
3992 any agreed authentication will also take place.
3996 argument is used, the relevant compression layer is opened.
3997 Again, if it is already open, it will be renegotiated.
4001 argument is used, the link will be brought up as normal, but if
4002 IPCP is already open, it will be renegotiated and the network
4003 interface will be reconfigured.
4005 It is probably not good practice to re-open the PPP state machines
4006 like this as it is possible that the peer will not behave correctly.
4009 however useful as a way of forcing the CCP or VJ dictionaries to be reset.
4011 Specify the password required for access to the full
4014 This password is required when connecting to the diagnostic port (see the
4025 logging is active, instead, the literal string
4031 is executed from the controlling connection or from a command file,
4032 ppp will exit after closing all connections.
4033 Otherwise, if the user
4034 is connected to a diagnostic socket, the connection is simply dropped.
4040 will exit despite the source of the command after closing all existing
4043 This command removes the given link.
4044 It is only really useful in multi-link mode.
4045 A link must be in the
4047 state before it is removed.
4048 .It rename|mv Ar name
4049 This command renames the given link to
4053 is already used by another link.
4055 The default link name is
4062 may make the log file more readable.
4063 .It resolv Ar command
4064 This command controls
4071 starts up, it loads the contents of this file into memory and retains this
4072 image for future use.
4074 is one of the following:
4075 .Bl -tag -width readonly
4078 .Pa /etc/resolv.conf
4084 will still attempt to negotiate nameservers with the peer, making the results
4090 This is the opposite of the
4095 .Pa /etc/resolv.conf
4097 This may be necessary if for example a DHCP client overwrote
4098 .Pa /etc/resolv.conf .
4101 .Pa /etc/resolv.conf
4102 with the version originally read at startup or with the last
4105 This is sometimes a useful command to put in the
4106 .Pa /etc/ppp/ppp.linkdown
4110 .Pa /etc/resolv.conf
4112 This command will work even if the
4114 command has been used.
4115 It may be useful as a command in the
4116 .Pa /etc/ppp/ppp.linkup
4117 file if you wish to defer updating
4118 .Pa /etc/resolv.conf
4119 until after other commands have finished.
4124 .Pa /etc/resolv.conf
4129 successfully negotiates a DNS.
4130 This is the opposite of the
4135 This option is not (yet) implemented.
4139 to identify itself to the peer.
4140 The link must be in LCP state or higher.
4141 If no identity has been set (via the
4147 When an identity has been set,
4149 will automatically identify itself when it sends or receives a configure
4150 reject, when negotiation fails or when LCP reaches the opened state.
4152 Received identification packets are logged to the LCP log (see
4154 for details) and are never responded to.
4159 This option allows the setting of any of the following variables:
4161 .It set accmap Ar hex-value
4162 ACCMap stands for Asynchronous Control Character Map.
4164 negotiated with the peer, and defaults to a value of 00000000 in hex.
4165 This protocol is required to defeat hardware that depends on passing
4166 certain characters from end to end (such as XON/XOFF etc).
4168 For the XON/XOFF scenario, use
4169 .Dq set accmap 000a0000 .
4170 .It set Oo auth Oc Ns Xo
4173 This sets the authentication key (or password) used in client mode
4174 PAP or CHAP negotiation to the given value.
4175 It also specifies the
4176 password to be used in the dial or login scripts in place of the
4178 sequence, preventing the actual password from being logged.
4183 logging is in effect,
4187 for security reasons.
4189 If the first character of
4191 is an exclamation mark
4194 treats the remainder of the string as a program that must be executed
4206 it is treated as a single literal
4208 otherwise, ignoring the
4211 is parsed as a program to execute in the same was as the
4213 command above, substituting special names in the same manner.
4216 will feed the program three lines of input, each terminated by a newline
4220 The host name as sent in the CHAP challenge.
4222 The challenge string as sent in the CHAP challenge.
4228 Two lines of output are expected:
4233 to be sent with the CHAP response.
4237 which is encrypted with the challenge and request id, the answer being sent
4238 in the CHAP response packet.
4243 in this manner, it is expected that the host challenge is a series of ASCII
4244 digits or characters.
4245 An encryption device or Secure ID card is usually
4246 required to calculate the secret appropriate for the given challenge.
4247 .It set authname Ar id
4248 This sets the authentication id used in client mode PAP or CHAP negotiation.
4252 mode with CHAP enabled,
4254 is used in the initial authentication challenge and should normally be set to
4255 the local machine name.
4257 .Ar min-percent max-percent period
4259 These settings apply only in multi-link mode and default to zero, zero and
4265 mode link is available, only the first link is made active when
4267 first reads data from the tun device.
4270 link will be opened only when the current bundle throughput is at least
4272 percent of the total bundle bandwidth for
4275 When the current bundle throughput decreases to
4277 percent or less of the total bundle bandwidth for
4281 link will be brought down as long as it is not the last active link.
4283 Bundle throughput is measured as the maximum of inbound and outbound
4286 The default values cause
4288 links to simply come up one at a time.
4290 Certain devices cannot determine their physical bandwidth, so it
4291 is sometimes necessary to use the
4293 command (described below) to make
4296 .It set bandwidth Ar value
4297 This command sets the connection bandwidth in bits per second.
4299 must be greater than zero.
4300 It is currently only used by the
4303 .It set callback Ar option Ns No ...
4304 If no arguments are given, callback is disabled, otherwise,
4308 mode, will accept) one of the given
4309 .Ar option Ns No s .
4310 In client mode, if an
4314 will request a different
4316 until no options remain at which point
4318 will terminate negotiations (unless
4320 is one of the specified
4324 will accept any of the given protocols - but the client
4326 request one of them.
4327 If you wish callback to be optional, you must {include}
4333 are as follows (in this order of preference):
4336 The callee is expected to decide the callback number based on
4340 is the callee, the number should be specified as the fifth field of
4342 .Pa /etc/ppp/ppp.secret .
4344 Microsoft's callback control protocol is used.
4349 If you wish to negotiate
4351 in client mode but also wish to allow the server to request no callback at
4352 CBCP negotiation time, you must specify both
4356 as callback options.
4358 .Ar number Ns Op , Ns Ar number Ns
4361 The caller specifies the
4367 should be either a comma separated list of allowable numbers or a
4369 meaning any number is permitted.
4372 is the caller, only a single number should be specified.
4374 Note, this option is very unsafe when used with a
4376 as a malicious caller can tell
4378 to call any (possibly international) number without first authenticating
4381 If the peer does not wish to do callback at all,
4383 will accept the fact and continue without callback rather than terminating
4385 This is required (in addition to one or more other callback
4386 options) if you wish callback to be optional.
4389 .No *| Ns Ar number Ns Oo
4390 .No , Ns Ar number Ns ...\& Oc
4391 .Op Ar delay Op Ar retry
4393 If no arguments are given, CBCP (Microsoft's CallBack Control Protocol)
4394 is disabled - ie, configuring CBCP in the
4396 command will result in
4398 requesting no callback in the CBCP phase.
4401 attempts to use the given phone
4402 .Ar number Ns No (s).
4407 will insist that the client uses one of these numbers, unless
4409 is used in which case the client is expected to specify the number.
4413 will attempt to use one of the given numbers (whichever it finds to
4414 be agreeable with the peer), or if
4418 will expect the peer to specify the number.
4420 .No off| Ns Ar seconds Ns Op !\&
4424 checks for the existence of carrier depending on the type of device
4425 that has been opened:
4426 .Bl -tag -width XXX -offset XXX
4427 .It Terminal Devices
4428 Carrier is checked one second after the login script is complete.
4431 assumes that this is because the device does not support carrier (which
4434 NULL-modem cables), logs the fact and stops checking
4437 As ptys do not support the TIOCMGET ioctl, the tty device will switch all
4438 carrier detection off when it detects that the device is a pty.
4439 .It PPPoE (netgraph) Devices
4440 Carrier is checked once per second for 5 seconds.
4441 If it is not set after
4442 the fifth second, the connection attempt is considered to have failed and
4443 the device is closed.
4444 Carrier is always required for PPPoE devices.
4447 All other device types do not support carrier.
4448 Setting a carrier value will
4449 result in a warning when the device is opened.
4451 Some modems take more than one second after connecting to assert the carrier
4453 If this delay is not increased, this will result in
4455 inability to detect when the link is dropped, as
4457 assumes that the device is not asserting carrier.
4461 command overrides the default carrier behaviour.
4463 specifies the maximum number of seconds that
4465 should wait after the dial script has finished before deciding if
4466 carrier is available or not.
4472 will not check for carrier on the device, otherwise
4474 will not proceed to the login script until either carrier is detected
4477 has elapsed, at which point
4479 assumes that the device will not set carrier.
4481 If no arguments are given, carrier settings will go back to their default
4486 is followed immediately by an exclamation mark
4492 If carrier is not detected after
4494 seconds, the link will be disconnected.
4495 .It set choked Op Ar timeout
4496 This sets the number of seconds that
4498 will keep a choked output queue before dropping all pending output packets.
4501 is less than or equal to zero or if
4503 is not specified, it is set to the default value of
4506 A choked output queue occurs when
4508 has read a certain number of packets from the local network for transmission,
4509 but cannot send the data due to link failure (the peer is busy etc.).
4511 will not read packets indefinitely.
4512 Instead, it reads up to
4518 packets in multi-link mode), then stops reading the network interface
4521 seconds have passed or at least one packet has been sent.
4525 seconds pass, all pending output packets are dropped.
4526 .It set ctsrts|crtscts on|off
4527 This sets hardware flow control.
4528 Hardware flow control is
4531 .It set deflate Ar out-winsize Op Ar in-winsize
4532 This sets the DEFLATE algorithms default outgoing and incoming window
4538 must be values between
4546 will insist that this window size is used and will not accept any other
4547 values from the peer.
4548 .It set dns Op Ar primary Op Ar secondary
4549 This command specifies DNS overrides for the
4554 command description above for details.
4555 This command does not affect the IP numbers requested using
4557 .It set device|line Xo
4560 This sets the device(s) to which
4562 will talk to the given
4565 All serial device names are expected to begin with
4567 Serial devices are usually called
4574 it must either begin with an exclamation mark
4577 .No PPPoE: Ns Ar iface Ns Xo
4578 .Op \&: Ns Ar provider Ns
4582 enabled systems), or be of the format
4584 .Ar host : port Op /tcp|udp .
4587 If it begins with an exclamation mark, the rest of the device name is
4588 treated as a program name, and that program is executed when the device
4590 Standard input, output and error are fed back to
4592 and are read and written as if they were a regular device.
4595 .No PPPoE: Ns Ar iface Ns Xo
4596 .Op \&: Ns Ar provider Ns
4598 specification is given,
4600 will attempt to create a
4602 over Ethernet connection using the given
4610 will attempt to load it using
4612 If this fails, an external program must be used such as the
4614 program available under
4618 is passed as the service name in the PPPoE Discovery Initiation (PADI)
4620 If no provider is given, an empty value will be used.
4622 When a PPPoE connection is established,
4624 will place the name of the Access Concentrator in the environment variable
4631 for further details.
4634 .Ar host Ns No : Ns Ar port Ns Oo
4637 specification is given,
4639 will attempt to connect to the given
4647 suffix is not provided, the default is
4649 Refer to the section on
4650 .Em PPP OVER TCP and UDP
4651 above for further details.
4657 will attempt to open each one in turn until it succeeds or runs out of
4659 .It set dial Ar chat-script
4660 This specifies the chat script that will be used to dial the other
4667 and to the example configuration files for details of the chat script
4669 It is possible to specify some special
4671 in your chat script as follows:
4674 When used as the last character in a
4676 string, this indicates that a newline should not be appended.
4678 When the chat script encounters this sequence, it delays two seconds.
4680 When the chat script encounters this sequence, it delays for one quarter of
4683 This is replaced with a newline character.
4685 This is replaced with a carriage return character.
4687 This is replaced with a space character.
4689 This is replaced with a tab character.
4691 This is replaced by the current phone number (see
4695 This is replaced by the current
4701 This is replaced by the current
4708 Note that two parsers will examine these escape sequences, so in order to
4711 see the escape character, it is necessary to escape it from the
4712 .Sq command parser .
4713 This means that in practice you should use two escapes, for example:
4714 .Bd -literal -offset indent
4715 set dial "... ATDT\\\\T CONNECT"
4718 It is also possible to execute external commands from the chat script.
4719 To do this, the first character of the expect or send string is an
4722 If a literal exclamation mark is required, double it up to
4724 and it will be treated as a single literal
4726 When the command is executed, standard input and standard output are
4727 directed to the open device (see the
4729 command), and standard error is read by
4731 and substituted as the expect or send string.
4734 is running in interactive mode, file descriptor 3 is attached to
4737 For example (wrapped for readability):
4738 .Bd -literal -offset indent
4739 set login "TIMEOUT 5 \\"\\" \\"\\" login:--login: ppp \e
4740 word: ppp \\"!sh \\\\-c \\\\\\"echo \\\\-n label: >&2\\\\\\"\\" \e
4741 \\"!/bin/echo in\\" HELLO"
4744 would result in the following chat sequence (output using the
4745 .Sq set log local chat
4746 command before dialing):
4747 .Bd -literal -offset indent
4752 Chat: Expecting: login:--login:
4753 Chat: Wait for (5): login:
4755 Chat: Expecting: word:
4756 Chat: Wait for (5): word:
4758 Chat: Expecting: !sh \\-c "echo \\-n label: >&2"
4759 Chat: Exec: sh -c "echo -n label: >&2"
4760 Chat: Wait for (5): !sh \\-c "echo \\-n label: >&2" --> label:
4761 Chat: Exec: /bin/echo in
4763 Chat: Expecting: HELLO
4764 Chat: Wait for (5): HELLO
4768 Note (again) the use of the escape character, allowing many levels of
4770 Here, there are four parsers at work.
4771 The first parses the original line, reading it as three arguments.
4772 The second parses the third argument, reading it as 11 arguments.
4773 At this point, it is
4776 signs are escaped, otherwise this parser will see them as constituting
4777 an expect-send-expect sequence.
4780 character is seen, the execution parser reads the first command as three
4783 itself expands the argument after the
4785 As we wish to send the output back to the modem, in the first example
4786 we redirect our output to file descriptor 2 (stderr) so that
4788 itself sends and logs it, and in the second example, we just output to stdout,
4789 which is attached directly to the modem.
4791 This, of course means that it is possible to execute an entirely external
4793 command rather than using the internal one.
4796 for a good alternative.
4798 The external command that is executed is subjected to the same special
4799 word expansions as the
4802 .It set enddisc Op label|IP|MAC|magic|psn value
4803 This command sets our local endpoint discriminator.
4804 If set prior to LCP negotiation, and if no
4806 command has been used,
4808 will send the information to the peer using the LCP endpoint discriminator
4810 The following discriminators may be set:
4811 .Bl -tag -width indent
4813 The current label is used.
4815 Our local IP number is used.
4816 As LCP is negotiated prior to IPCP, it is
4817 possible that the IPCP layer will subsequently change this value.
4819 it does, the endpoint discriminator stays at the old value unless manually
4822 This is similar to the
4824 option above, except that the MAC address associated with the local IP
4826 If the local IP number is not resident on any Ethernet
4827 interface, the command will fail.
4829 As the local IP number defaults to whatever the machine host name is,
4831 is usually done prior to any
4835 A 20 digit random number is used.
4836 Care should be taken when using magic numbers as restarting
4838 or creating a link using a different
4840 invocation will also use a different magic number and will therefore not
4841 be recognised by the peer as belonging to the same bundle.
4842 This makes it unsuitable for
4850 should be set to an absolute public switched network number with the
4854 If no arguments are given, the endpoint discriminator is reset.
4855 .It set escape Ar value...
4856 This option is similar to the
4859 It allows the user to specify a set of characters that will be
4861 as they travel across the link.
4862 .It set filter dial|alive|in|out Ar rule-no Xo
4863 .No permit|deny|clear| Ns Ar rule-no
4866 .Ar src_addr Ns Op / Ns Ar width
4867 .Op Ar dst_addr Ns Op / Ns Ar width
4869 .Op src lt|eq|gt Ar port
4870 .Op dst lt|eq|gt Ar port
4874 .Op timeout Ar secs ]
4877 supports four filter sets.
4880 filter specifies packets that keep the connection alive - resetting the
4884 filter specifies packets that cause
4891 filter specifies packets that are allowed to travel
4892 into the machine and the
4894 filter specifies packets that are allowed out of the machine.
4896 Filtering is done prior to any IP alterations that might be done by the
4897 NAT engine on outgoing packets and after any IP alterations that might
4898 be done by the NAT engine on incoming packets.
4899 By default all empty filter sets allow all packets to pass.
4900 Rules are processed in order according to
4902 (unless skipped by specifying a rule number as the
4904 Up to 40 rules may be given for each set.
4905 If a packet does not match
4906 any of the rules in a given set, it is discarded.
4911 filters, this means that the packet is dropped.
4914 filters it means that the packet will not reset the idle timer (even if
4916 .Ar in Ns No / Ns Ar out
4919 value) and in the case of
4921 filters it means that the packet will not trigger a dial.
4922 A packet failing to trigger a dial will be dropped rather than queued.
4925 .Sx PACKET FILTERING
4926 above for further details.
4927 .It set hangup Ar chat-script
4928 This specifies the chat script that will be used to reset the device
4929 before it is closed.
4930 It should not normally be necessary, but can
4931 be used for devices that fail to reset themselves properly on close.
4932 .It set help|? Op Ar command
4933 This command gives a summary of available set commands, or if
4935 is specified, the command usage is shown.
4936 .It set ifaddr Oo Ar myaddr Ns
4938 .Oo Ar hisaddr Ns Op / Ns Ar \&nn
4943 This command specifies the IP addresses that will be used during
4945 Addresses are specified using the format
4951 is the preferred IP, but
4953 specifies how many bits of the address we will insist on.
4956 is omitted, it defaults to
4958 unless the IP address is 0.0.0.0 in which case it defaults to
4961 If you wish to assign a dynamic IP number to the peer,
4963 may also be specified as a range of IP numbers in the format
4964 .Bd -ragged -offset indent
4965 .Ar \&IP Ns Oo \&- Ns Ar \&IP Ns Oc Ns Oo , Ns Ar \&IP Ns
4966 .Oo \&- Ns Ar \&IP Ns Oc Oc Ns ...
4971 .Dl set ifaddr 10.0.0.1 10.0.1.2-10.0.1.10,10.0.1.20
4975 as the local IP number, but may assign any of the given 10 IP
4976 numbers to the peer.
4977 If the peer requests one of these numbers,
4978 and that number is not already in use,
4980 will grant the peers request.
4981 This is useful if the peer wants
4982 to re-establish a link using the same IP number as was previously
4983 allocated (thus maintaining any existing tcp or udp connections).
4985 If the peer requests an IP number that is either outside
4986 of this range or is already in use,
4988 will suggest a random unused IP number from the range.
4992 is specified, it is used in place of
4994 in the initial IPCP negotiation.
4995 However, only an address in the
4997 range will be accepted.
4998 This is useful when negotiating with some
5000 implementations that will not assign an IP number unless their peer
5004 It should be noted that in
5008 will configure the interface immediately upon reading the
5010 line in the config file.
5011 In any other mode, these values are just
5012 used for IPCP negotiations, and the interface is not configured
5013 until the IPCP layer is up.
5017 argument may be overridden by the third field in the
5019 file once the client has authenticated itself
5023 .Sx AUTHENTICATING INCOMING CONNECTIONS
5024 section for details.
5026 In all cases, if the interface is already configured,
5028 will try to maintain the interface IP numbers so that any existing
5029 bound sockets will remain valid.
5030 .It set ifqueue Ar packets
5031 Set the maximum number of packets that
5033 will read from the tunnel interface while data cannot be sent to any of
5034 the available links.
5035 This queue limit is necessary to flow control outgoing data as the tunnel
5036 interface is likely to be far faster than the combined links available to
5041 is set to a value less than the number of links,
5043 will read up to that value regardless.
5044 This prevents any possible latency problems.
5046 The default value for
5050 .It set ccpretry|ccpretries Oo Ar timeout
5051 .Op Ar reqtries Op Ar trmtries
5053 .It set chapretry|chapretries Oo Ar timeout
5056 .It set ipcpretry|ipcpretries Oo Ar timeout
5057 .Op Ar reqtries Op Ar trmtries
5059 .It set ipv6cpretry|ipv6cpretries Oo Ar timeout
5060 .Op Ar reqtries Op Ar trmtries
5062 .It set lcpretry|lcpretries Oo Ar timeout
5063 .Op Ar reqtries Op Ar trmtries
5065 .It set papretry|papretries Oo Ar timeout
5068 These commands set the number of seconds that
5070 will wait before resending Finite State Machine (FSM) Request packets.
5073 for all FSMs is 3 seconds (which should suffice in most cases).
5077 is specified, it tells
5079 how many configuration request attempts it should make while receiving
5080 no reply from the peer before giving up.
5081 The default is 5 attempts for
5082 CCP, LCP and IPCP and 3 attempts for PAP and CHAP.
5086 is specified, it tells
5088 how many terminate requests should be sent before giving up waiting for the
5090 The default is 3 attempts.
5091 Authentication protocols are
5092 not terminated and it is therefore invalid to specify
5096 In order to avoid negotiations with the peer that will never converge,
5098 will only send at most 3 times the configured number of
5100 in any given negotiation session before giving up and closing that layer.
5106 This command allows the adjustment of the current log level.
5107 Refer to the Logging Facility section for further details.
5108 .It set login Ar chat-script
5111 compliments the dial-script.
5112 If both are specified, the login
5113 script will be executed after the dial script.
5114 Escape sequences available in the dial script are also available here.
5115 .It set logout Ar chat-script
5116 This specifies the chat script that will be used to logout
5117 before the hangup script is called.
5118 It should not normally be necessary.
5119 .It set lqrperiod|echoperiod Ar frequency
5120 This command sets the
5127 The default is 30 seconds.
5128 You must also use the
5132 commands if you wish to send
5136 requests to the peer.
5137 .It set mode Ar interactive|auto|ddial|background
5138 This command allows you to change the
5140 of the specified link.
5141 This is normally only useful in multi-link mode,
5142 but may also be used in uni-link mode.
5144 It is not possible to change a link that is
5149 Note: If you issue the command
5151 and have network address translation enabled, it may be useful to
5152 .Dq enable iface-alias
5156 to do the necessary address translations to enable the process that
5157 triggers the connection to connect once the link is up despite the
5158 peer assigning us a new (dynamic) IP address.
5159 .It set mppe Op 40|56|128|* Op stateless|stateful|*
5160 This option selects the encryption parameters used when negotiation
5162 MPPE can be disabled entirely with the
5165 If no arguments are given,
5167 will attempt to negotiate a stateful link with a 128 bit key, but
5168 will agree to whatever the peer requests (including no encryption
5171 If any arguments are given,
5175 on using MPPE and will close the link if it is rejected by the peer (Note;
5176 this behaviour can be overridden by a configured RADIUS server).
5178 The first argument specifies the number of bits that
5180 should insist on during negotiations and the second specifies whether
5182 should insist on stateful or stateless mode.
5183 In stateless mode, the
5184 encryption dictionary is re-initialised with every packet according to
5185 an encryption key that is changed with every packet.
5187 the encryption dictionary is re-initialised every 256 packets or after
5188 the loss of any data and the key is changed every 256 packets.
5189 Stateless mode is less efficient but is better for unreliable transport
5191 .It set mrru Op Ar value
5192 Setting this option enables Multi-link PPP negotiations, also known as
5193 Multi-link Protocol or MP.
5194 There is no default MRRU (Maximum Reconstructed Receive Unit) value.
5195 If no argument is given, multi-link mode is disabled.
5200 The default MRU (Maximum Receive Unit) is 1500.
5201 If it is increased, the other side *may* increase its MTU.
5202 In theory there is no point in decreasing the MRU to below the default as the
5204 protocol says implementations *must* be able to accept packets of at
5211 will refuse to negotiate a higher value.
5212 The maximum MRU can be set to 2048 at most.
5213 Setting a maximum of less than 1500 violates the
5215 rfc, but may sometimes be necessary.
5218 imposes a maximum of 1492 due to hardware limitations.
5220 If no argument is given, 1500 is assumed.
5221 A value must be given when
5228 The default MTU is 1500.
5229 At negotiation time,
5231 will accept whatever MRU the peer requests (assuming it is
5232 not less than 296 bytes or greater than the assigned maximum).
5235 will not accept MRU values less than
5237 When negotiations are complete, the MTU is used when writing to the
5238 interface, even if the peer requested a higher value MRU.
5239 This can be useful for
5240 limiting your packet size (giving better bandwidth sharing at the expense
5241 of more header data).
5247 will refuse to negotiate a higher value.
5248 The maximum MTU can be set to 2048 at most.
5249 Note, it is necessary to use the
5251 keyword to limit the MTU when using PPPoE.
5255 is given, 1500, or whatever the peer asks for is used.
5256 A value must be given when
5259 .It set nbns Op Ar x.x.x.x Op Ar y.y.y.y
5260 This option allows the setting of the Microsoft NetBIOS name server
5261 values to be returned at the peers request.
5262 If no values are given,
5264 will reject any such requests.
5265 .It set openmode active|passive Op Ar delay
5274 will always initiate LCP/IPCP/CCP negotiation one second after the line
5276 If you want to wait for the peer to initiate negotiations, you
5279 If you want to initiate negotiations immediately or after more than one
5280 second, the appropriate
5282 may be specified here in seconds.
5283 .It set parity odd|even|none|mark
5284 This allows the line parity to be set.
5285 The default value is
5287 .It set phone Ar telno Ns Xo
5288 .Oo \&| Ns Ar backupnumber Oc Ns ... Ns Oo : Ns Ar nextnumber Oc Ns ... Xc
5289 This allows the specification of the phone number to be used in
5290 place of the \\\\T string in the dial and login chat scripts.
5291 Multiple phone numbers may be given separated either by a pipe
5296 Numbers after the pipe are only dialed if the dial or login
5297 script for the previous number failed.
5299 Numbers after the colon are tried sequentially, irrespective of
5300 the reason the line was dropped.
5302 If multiple numbers are given,
5304 will dial them according to these rules until a connection is made, retrying
5305 the maximum number of times specified by
5310 mode, each number is attempted at most once.
5311 .It set pppoe Op standard|3Com
5312 This option configures the underlying
5314 node to either standard RFC2516 PPPoE or proprietary 3Com mode.
5315 If not set the system default will be used.
5316 .It set Oo proc Oc Ns Xo
5317 .No title Op Ar value
5319 The current process title as displayed by
5321 is changed according to
5325 is not specified, the original process title is restored.
5327 word replacements done by the shell commands (see the
5329 command above) are done here too.
5331 Note, if USER is required in the process title, the
5333 command must appear in
5335 as it is not known when the commands in
5338 .It set radius Op Ar config-file
5339 This command enables RADIUS support (if it is compiled in).
5341 refers to the radius client configuration file as described in
5343 If PAP, CHAP, MSCHAP or MSCHAPv2 are
5344 .Dq enable Ns No d ,
5347 .Em \&N Ns No etwork
5350 and uses the configured RADIUS server to authenticate rather than
5351 authenticating from the
5353 file or from the passwd database.
5355 If none of PAP, CHAP, MSCHAP or MSCHAPv2 are enabled,
5360 uses the following attributes from the RADIUS reply:
5361 .Bl -tag -width XXX -offset XXX
5362 .It RAD_FRAMED_IP_ADDRESS
5363 The peer IP address is set to the given value.
5364 .It RAD_FRAMED_IP_NETMASK
5365 The tun interface netmask is set to the given value.
5367 If the given MTU is less than the peers MRU as agreed during LCP
5368 negotiation, *and* it is less that any configured MTU (see the
5370 command), the tun interface MTU is set to the given value.
5371 .It RAD_FRAMED_COMPRESSION
5372 If the received compression type is
5375 will request VJ compression during IPCP negotiations despite any
5377 configuration command.
5379 If this attribute is supplied,
5381 will attempt to use it as an additional label to load from the
5386 The load will be attempted before (and in addition to) the normal
5388 If the label does not exist, no action is taken and
5390 proceeds to the normal load using the current label.
5391 .It RAD_FRAMED_ROUTE
5392 The received string is expected to be in the format
5393 .Ar dest Ns Op / Ns Ar bits
5396 Any specified metrics are ignored.
5400 are understood as valid values for
5407 to specify the default route, and
5409 is understood to be the same as
5418 For example, a returned value of
5419 .Dq 1.2.3.4/24 0.0.0.0 1 2 -1 3 400
5420 would result in a routing table entry to the 1.2.3.0/24 network via
5422 and a returned value of
5426 would result in a default route to
5429 All RADIUS routes are applied after any sticky routes are applied, making
5430 RADIUS routes override configured routes.
5431 This also applies for RADIUS routes that do not {include} the
5436 .It RAD_FRAMED_IPV6_PREFIX
5437 If this attribute is supplied, the value is substituted for IPV6PREFIX
5439 You may pass it to an upper layer protocol such as DHCPv6 for delegating an
5440 IPv6 prefix to a peer.
5441 .It RAD_FRAMED_IPV6_ROUTE
5442 The received string is expected to be in the format
5443 .Ar dest Ns Op / Ns Ar bits
5446 Any specified metrics are ignored.
5450 are understood as valid values for
5457 to specify the default route, and
5459 is understood to be the same as
5468 For example, a returned value of
5469 .Dq 3ffe:505:abcd::/48 ::
5470 would result in a routing table entry to the 3ffe:505:abcd::/48 network via
5472 and a returned value of
5475 .Dq default HISADDR6
5476 would result in a default route to
5479 All RADIUS IPv6 routes are applied after any sticky routes are
5480 applied, making RADIUS IPv6 routes override configured routes.
5482 also applies for RADIUS IPv6 routes that do not {include} the
5487 .It RAD_SESSION_TIMEOUT
5488 If supplied, the client connection is closed after the given number of
5490 .It RAD_REPLY_MESSAGE
5491 If supplied, this message is passed back to the peer as the authentication
5493 .It RAD_MICROSOFT_MS_CHAP_ERROR
5495 .Dv RAD_VENDOR_MICROSOFT
5496 vendor specific attribute is supplied, it is passed back to the peer as the
5497 authentication FAILURE text.
5498 .It RAD_MICROSOFT_MS_CHAP2_SUCCESS
5500 .Dv RAD_VENDOR_MICROSOFT
5501 vendor specific attribute is supplied and if MS-CHAPv2 authentication is
5502 being used, it is passed back to the peer as the authentication SUCCESS text.
5503 .It RAD_MICROSOFT_MS_MPPE_ENCRYPTION_POLICY
5505 .Dv RAD_VENDOR_MICROSOFT
5506 vendor specific attribute is supplied and has a value of 2 (Required),
5508 will insist that MPPE encryption is used (even if no
5510 configuration command has been given with arguments).
5511 If it is supplied with a value of 1 (Allowed), encryption is made optional
5514 configuration commands with arguments).
5515 .It RAD_MICROSOFT_MS_MPPE_ENCRYPTION_TYPES
5517 .Dv RAD_VENDOR_MICROSOFT
5518 vendor specific attribute is supplied, bits 1 and 2 are examined.
5519 If either or both are set, 40 bit and/or 128 bit (respectively) encryption
5520 options are set, overriding any given first argument to the
5523 Note, it is not currently possible for the RADIUS server to specify 56 bit
5525 .It RAD_MICROSOFT_MS_MPPE_RECV_KEY
5527 .Dv RAD_VENDOR_MICROSOFT
5528 vendor specific attribute is supplied, it is value is used as the master
5529 key for decryption of incoming data.
5530 When clients are authenticated using
5531 MSCHAPv2, the RADIUS server MUST provide this attribute if inbound MPPE is
5533 .It RAD_MICROSOFT_MS_MPPE_SEND_KEY
5535 .Dv RAD_VENDOR_MICROSOFT
5536 vendor specific attribute is supplied, it is value is used as the master
5537 key for encryption of outgoing data.
5538 When clients are authenticated using
5539 MSCHAPv2, the RADIUS server MUST provide this attribute if outbound MPPE is
5543 Values received from the RADIUS server may be viewed using
5545 .It set rad_alive Ar timeout
5546 When RADIUS is configured, setting
5552 to sent RADIUS accounting information to the RADIUS server every
5555 .It set rad_port_id Ar option
5556 When RADIUS is configured, setting the
5558 value specifies what should be sent to the RADIUS server as
5565 PID of the corresponding tunnel.
5570 index of the interface as returned by
5571 .Xr if_nametoindex 3 .
5573 keeps the default behavior.
5575 .It set reconnect Ar timeout ntries
5576 Should the line drop unexpectedly (due to loss of CD or LQR
5577 failure), a connection will be re-established after the given
5579 The line will be re-connected at most
5588 will result in a variable pause, somewhere between 1 and 30 seconds.
5589 .It set recvpipe Op Ar value
5590 This sets the routing table RECVPIPE value.
5591 The optimum value is just over twice the MTU value.
5594 is unspecified or zero, the default kernel controlled value is used.
5595 .It set redial Ar secs Ns Xo
5597 .Oo - Ns Ar max Ns Oc Oc Ns
5602 can be instructed to attempt to redial
5605 If more than one phone number is specified (see
5609 is taken before dialing each number.
5612 is taken before starting at the first number again.
5615 may be used here in place of
5619 causing a random delay of between 1 and 30 seconds.
5623 is specified, its value is added onto
5629 will only be incremented at most
5637 delay will be effective, even after
5639 has been exceeded, so an immediate manual dial may appear to have
5641 If an immediate dial is required, a
5643 should immediately follow the
5648 description above for further details.
5649 .It set sendpipe Op Ar value
5650 This sets the routing table SENDPIPE value.
5651 The optimum value is just over twice the MTU value.
5654 is unspecified or zero, the default kernel controlled value is used.
5655 .It "set server|socket" Ar TcpPort Ns No \&| Ns Xo
5656 .Ar LocalName Ns No |none|open|closed
5657 .Op password Op Ar mask
5661 to listen on the given socket or
5663 for incoming command connections.
5669 to close any existing socket and clear the socket configuration.
5674 to attempt to re-open the port.
5679 to close the open port.
5681 If you wish to specify a local domain socket,
5683 must be specified as an absolute file name, otherwise it is assumed
5684 to be the name or number of a TCP port.
5685 You may specify the octal umask to be used with a local domain socket.
5691 for details of how to translate TCP port names.
5693 You must also specify the password that must be entered by the client
5696 variable above) when connecting to this socket.
5698 specified as an empty string, no password is required for connecting clients.
5700 When specifying a local domain socket, the first
5702 sequence found in the socket name will be replaced with the current
5703 interface unit number.
5704 This is useful when you wish to use the same
5705 profile for more than one connection.
5707 In a similar manner TCP sockets may be prefixed with the
5709 character, in which case the current interface unit number is added to
5714 with a server socket, the
5716 command is the preferred mechanism of communications.
5719 can also be used, but link encryption may be implemented in the future, so
5727 interact with the diagnostic socket.
5728 .It set speed Ar value
5729 This sets the speed of the serial device.
5730 If speed is specified as
5733 treats the device as a synchronous device.
5735 Certain device types will know whether they should be specified as
5736 synchronous or asynchronous.
5737 These devices will override incorrect
5738 settings and log a warning to this effect.
5739 .It set stopped Op Ar LCPseconds Op Ar CCPseconds
5740 If this option is set,
5742 will time out after the given FSM (Finite State Machine) has been in
5743 the stopped state for the given number of
5745 This option may be useful if the peer sends a terminate request,
5746 but never actually closes the connection despite our sending a terminate
5748 This is also useful if you wish to
5749 .Dq set openmode passive
5750 and time out if the peer does not send a Configure Request within the
5753 .Dq set log +lcp +ccp
5756 log the appropriate state transitions.
5758 The default value is zero, where
5760 does not time out in the stopped state.
5762 This value should not be set to less than the openmode delay (see
5765 .It set timeout Ar idleseconds Op Ar mintimeout
5766 This command allows the setting of the idle timer.
5767 Refer to the section titled
5768 .Sx SETTING THE IDLE TIMER
5769 for further details.
5775 will never idle out before the link has been up for at least that number
5783 This command controls the ports that
5785 prioritizes when transmitting data.
5786 The default priority TCP ports
5787 are ports 21 (ftp control), 22 (ssh), 23 (telnet), 513 (login), 514 (shell),
5788 543 (klogin) and 544 (kshell).
5789 There are no priority UDP ports by default.
5804 are given, the priority port lists are cleared (although if
5808 is specified, only that list is cleared).
5811 argument is prefixed with a plus
5815 the current list is adjusted, otherwise the list is reassigned.
5817 prefixed with a plus or not prefixed at all are added to the list and
5819 prefixed with a minus are removed from the list.
5823 is specified, all priority port lists are disabled and even
5825 packets are not prioritised.
5826 .It set urgent length Ar length
5827 This command tells ppp to prioritize small packets up to
5832 is not specified, or 0, this feature is disabled.
5833 .It set vj slotcomp on|off
5836 whether it should attempt to negotiate VJ slot compression.
5837 By default, slot compression is turned
5839 .It set vj slots Ar nslots
5840 This command sets the initial number of slots that
5842 will try to negotiate with the peer when VJ compression is enabled (see the
5845 It defaults to a value of 16.
5853 .It shell|! Op Ar command
5856 is not specified a shell is invoked according to the
5858 environment variable.
5859 Otherwise, the given
5862 Word replacement is done in the same way as for the
5864 command as described above.
5866 Use of the !\& character
5867 requires a following space as with any of the other commands.
5868 You should note that this command is executed in the foreground;
5870 will not continue running until this process has exited.
5873 command if you wish processing to happen in the background.
5875 This command allows the user to examine the following:
5878 Show the current bundle settings.
5880 Show the current CCP compression statistics.
5882 Show the current VJ compression statistics.
5884 Show the current escape characters.
5885 .It show filter Op Ar name
5886 List the current rules for the given filter.
5889 is not specified, all filters are shown.
5891 Show the current HDLC statistics.
5893 Give a summary of available show commands.
5895 Show the current interface information
5899 Show the current IPCP statistics.
5901 Show the protocol layers currently in use.
5903 Show the current LCP statistics.
5904 .It show Oo data Oc Ns Xo
5907 Show high level link information.
5909 Show a list of available logical links.
5911 Show the current log values.
5913 Show current memory statistics.
5915 Show the current NCP statistics.
5917 Show low level link information.
5919 Show Multi-link information.
5921 Show current protocol totals.
5923 Show the current routing tables.
5925 Show the current stopped timeouts.
5927 Show the active alarm timers.
5929 Show the current version number of
5933 Go into terminal mode.
5934 Characters typed at the keyboard are sent to the device.
5935 Characters read from the device are displayed on the screen.
5940 automatically enables Packet Mode and goes back into command mode.
5945 Read the example configuration files.
5946 They are a good source of information.
5955 to get online information about what is available.
5957 The following URLs contain useful information:
5958 .Bl -bullet -compact
5960 https://www.FreeBSD.org/doc/en_US.ISO8859-1/books/faq/ppp.html
5962 https://www.FreeBSD.org/doc/handbook/userppp.html
5967 refers to four files:
5973 These files are placed in the
5977 .It Pa /etc/ppp/ppp.conf
5978 System default configuration file.
5979 .It Pa /etc/ppp/ppp.secret
5980 An authorisation file for each system.
5981 .It Pa /etc/ppp/ppp.linkup
5982 A file to check when
5984 establishes a network level connection.
5985 .It Pa /etc/ppp/ppp.linkdown
5986 A file to check when
5988 closes a network level connection.
5989 .It Pa /var/log/ppp.log
5990 Logging and debugging information file.
5991 Note, this name is specified in
5992 .Pa /etc/syslog.conf .
5995 for further details.
5996 .It Pa /var/spool/lock/LCK..*
5997 tty port locking file.
6000 for further details.
6001 .It Pa /var/run/tunN.pid
6002 The process id (pid) of the
6004 program connected to the tunN device, where
6006 is the number of the device.
6007 .It Pa /var/run/ttyXX.if
6008 The tun interface used by this port.
6009 Again, this file is only created in
6015 .It Pa /etc/services
6016 Get port number if port number is using service name.
6017 .It Pa /var/run/ppp-authname-class-value
6018 In multi-link mode, local domain sockets are created using the peer
6021 the peer endpoint discriminator class
6023 and the peer endpoint discriminator value
6025 As the endpoint discriminator value may be a binary value, it is turned
6026 to HEX to determine the actual file name.
6028 This socket is used to pass links between different instances of
6070 This program was originally written by
6071 .An Toshiharu OHNO Aq Mt tony-o@iij.ad.jp ,
6072 and was submitted to
6075 .An Atsushi Murai Aq Mt amurai@spec.co.jp .
6077 It was substantially modified during 1997 by
6078 .An Brian Somers Aq Mt brian@Awfulhak.org ,
6081 in November that year
6082 (just after the 2.2 release).
6084 Most of the code was rewritten by
6086 in early 1998 when multi-link ppp support was added.
projects / FreeBSD / FreeBSD.git / blob