.Dd 20 September 1995 .Os FreeBSD .Dt PPP 8 .Sh NAME .Nm ppp .Nd Point to Point Protocol (a.k.a. iijppp) .Sh SYNOPSIS .Nm SOMEONE FIX ME ! The .Op macro can't handle enough args !
[ .Fl auto | .Fl background | .Fl ddial | .Fl direct | .Fl dedicated ] .Op Fl alias .Op Ar system .Sh DESCRIPTION This is a user process .Em PPP software package. Normally, .Em PPP is implemented as a part of the kernel (e.g. as managed by .Xr pppd 8 ) and it's thus somewhat hard to debug and/or modify its behaviour. However, in this implementation .Em PPP is done as a user process with the help of the tunnel device driver (tun). .Sh Major Features l -diag t Provides interactive user interface. Using its command mode, the user can easily enter commands to establish the connection with the remote end, check the status of connection and close the connection. All functions can also be optionally password protected for security. t Supports both manual and automatic dialing. Interactive mode has a .Dq term command which enables you to talk to your modem directly. When your modem is connected to the remote peer and it starts to talk .Em PPP , .Nm detects it and switches to packet mode automatically. Once you have determined the proper sequence for connecting with the remote host, you can write a chat script to define the necessary dialing and login procedure for later convenience. t Supports on-demand dialup capability. By using .Fl auto mode, .Nm will act as a daemon and wait for a packet to be sent over the .Em PPP link. When this happens, the daemon automatically dials and establishes the connection. In almost the same manner .Fl ddial mode (direct-dial mode) also automatically dials and establishes the connection. However, it differs in that it will dial the remote site any time it detects the link is down, even if there are no packets to be sent. This mode is useful for full-time connections where we worry less about line charges and more about being connected full time. A third .Fl dedicated mode is also available. This mode is targeted at a dedicated link between two machines. .Nm Ppp will never voluntarily quit from dedicated mode - you must send it the .Dq quit all command via its diagnostic socket. A .Dv SIGHUP will force an LCP renegotiation, and a .Dv SIGTERM will force it to exit. t Supports packet aliasing. Packet aliasing (a.k.a. IP masquerading) allows computers on a private, unregistered network to access the Internet. The .Em PPP host acts as a masquerading gateway. IP addresses as well as TCP and UDP port numbers are aliased for outgoing packets and de-aliased for returning packets. t Supports background PPP connections. In background mode, if .Nm successfully establishes the connection, it will become a daemon. Otherwise, it will exit with an error. This allows the setup of scripts that wish to execute certain commands only if the connection is successfully established. t Supports server-side PPP connections. In direct mode, .nm acts as server which accepts incoming .Em PPP connections on stdin/stdout. t Supports PAP and CHAP authentication. With PAP or CHAP, it is possible to skip the Unix style .Xr login 1 proceedure, and use the .Em PPP protocol for authentication instead. t Supports Proxy Arp. When .Em PPP is set up as server, you can also configure it to do proxy arp for your connection. t Supports packet filtering. User can define four kinds of filters: .Em ifilter for incoming packets, .Em ofilter for outgoing packets, .Em dfilter to define a dialing trigger packet and .Em afilter for keeping a connection alive with the trigger packet. t Tunnel driver supports bpf. The user can use .Xr tcpdump 1 to check the packet flow over the .Em PPP link. t Supports PPP over TCP capability. t Supports IETF draft Predictor-1 compression. .Nm supports not only VJ-compression but also Predictor-1 compression. Normally, a modem has built-in compression (e.g. v42.bis) and the system may receive higher data rates from it as a result of such compression. While this is generally a good thing in most other situations, this higher speed data imposes a penalty on the system by increasing the number of serial interrupts the system has to process in talking to the modem and also increases latency. Unlike VJ-compression, Predictor-1 compression pre-compresses .Em all data flowing through the link, thus reducing overhead to a minimum. t Supports Microsoft's IPCP extensions. Name Server Addresses and NetBIOS Name Server Addresses can be negotiated with clients using the Microsoft .Em PPP stack (ie. Win95, WinNT) .Sh PERMISSIONS .Nm Ppp is installed as user .Dv root and group .Dv network , with permissions .Dv 4550 . By default, .Nm will not run if the invoking user id is not zero. This may be overridden by using the .Dq allow users command in
a /etc/ppp/ppp.conf . When running as a normal user, .Nm switches to user id 0 in order to alter the system routing table, set up system lock files and read the ppp configuration files. All external commands (executed via the "shell" or "!bg" commands) are executed as the user id that invoked .Nm ppp . Refer to the .Sq ID0 logging facility if you're interested in what exactly is done as user id zero. .Sh GETTING STARTED When you first run .Nm you may need to deal with some initial configuration details. First, your kernel should include a tunnel device (the GENERIC kernel includes one by default). If it doesn't, or if you require more than one tun interface, you'll need to rebuild your kernel with the following line in your kernel configuration file: .Dl pseudo-device tun N where .Ar N is the maximum number of .Em PPP connections you wish to support. Second, check your
a /dev directory for the tunnel device entries
a /dev/tunN , where .Sq N represents the number of the tun device, starting at zero. If they don't exist, you can create them by running "sh ./MAKEDEV tunN". This will create tun devices 0 through .Ar N . Last of all, create a log file. .Nm Ppp uses .Xr syslog 3 to log information. A common log file name is
a /var/log/ppp.log . To make output go to this file, put the following lines in the
a /etc/syslog.conf file: .Dl !ppp .Dl *.*<TAB>/var/log/ppp.log Make sure you use actual TABs here. If you use spaces, the line will be silently ignored. It is possible to have more than one .Em PPP log file by creating a link to the .Nm executable: .Dl # cd /usr/sbin .Dl # ln ppp ppp0 and using .Dl !ppp0 .Dl *.* /var/log/ppp0.log in
a /etc/syslog.conf . Don't forget to send a .Dv HUP signal to .Xr syslogd 8 after altering
a /etc/syslog.conf . .Sh MANUAL DIALING In the following examples, we assume that your machine name is .Dv awfulhak . If you set your host name and password in
a /etc/ppp/ppp.secret , you can't do anything except run the help, passwd and quit commands. d -literal -offset indent ppp on "your host name"> help help : Display this message passwd : Password for security quit : Quit the PPP program ppp on awfulhak> pass <password> .Ed
p The "on" part of your prompt will change to "ON" if you specify the correct password. d -literal -offset indent ppp ON awfulhak> .Ed
p You can now specify the device name, speed and parity for your modem, and whether CTS/RTS signalling should be used (CTS/RTS is used by default). If your hardware does not provide CTS/RTS lines (as may happen when you are connected directly to certain PPP-capable terminal servers), .Nm will never send any output through the port; it waits for a signal which never comes. Thus, if you have a direct line and can't seem to make a connection, try turning CTS/RTS off: d -literal -offset indent ppp ON awfulhak> set line /dev/cuaa0 ppp ON awfulhak> set speed 38400 ppp ON awfulhak> set parity even ppp ON awfulhak> set ctsrts on ppp ON awfulhak> show modem * Modem related information is shown here * ppp ON awfulhak> .Ed
p The term command can now be used to talk directly with your modem: d -literal -offset indent ppp ON awfulhak> term at OK atdt123456 CONNECT login: ppp Password: Protocol: ppp .Ed
p When the peer starts to talk in .Em PPP , .Nm detects this automatically and returns to command mode. d -literal -offset indent ppp ON awfulhak> PPP ON awfulhak> .Ed
p You are now connected! Note that .Sq PPP in the prompt has changed to capital letters to indicate that you have a peer connection. The show command can be used to see how things are going: d -literal -offset indent PPP ON awfulhak> show lcp * LCP related information is shown here * PPP ON awfulhak> show ipcp * IPCP related information is shown here * .Ed
p At this point, your machine has a host route to the peer. This means that you can only make a connection with the host on the other side of the link. If you want to add a default route entry (telling your machine to send all packets without another routing entry to the other side of the .Em PPP link), enter the following command: d -literal -offset indent PPP ON awfulhak> add default HISADDR .Ed
p The string .Sq HISADDR represents the IP address of the connected peer. It is possible to use the keyword .Sq INTERFACE in place of .Sq HISADDR . This will create a direct route on the tun interface. You can now use your network applications (ping, telnet, ftp etc.) in other windows on your machine. Refer to the .Em PPP COMMAND LIST section for details on all available commands. .Sh AUTOMATIC DIALING To use automatic dialing, you must prepare some Dial and Login chat scripts. See the example definitions in
a /etc/ppp/ppp.conf.sample (the format of
a /etc/ppp/ppp.conf is pretty simple). Each line contains one comment, inclusion, label or command: l -bullet -compact t A line starting with a
q Dq # character is treated as a comment line. Leading whitespace are ignored when identifying comment lines. t An inclusion is a line beginning with the word .Sq !include . It must have one argument - the file to include. You may wish to .Dq !include ~/.ppp.conf for compatibility with older versions of .Nm ppp . t A label name starts in the first column and is followed by a colon
q Dq : . t A command line must contain a space or tab in the first column. .El
p The
a /etc/ppp/ppp.conf file should consist of at least a .Dq default section. This section is always executed. It should also contain one or more sections, named according to their purpose, for example, .Dq MyISP would represent your ISP, and .Dq ppp-in would represent an incoming .Nm configuration. You can now specify the destination label name when you invoke .Nm ppp . Commands associated with the .Dq default label are executed, followed by those associated with the destination label provided. When .Nm is started with no arguments, the .Dq default section is still executed. The load command can be used to manually load a section from the
a /etc/ppp/ppp.conf file: d -literal -offset indent PPP ON awfulhak> load MyISP .Ed
p Once the connection is made, the .Sq ppp portion of the prompt will change to .Sq PPP : d -literal -offset indent # ppp MyISP ... ppp ON awfulhak> dial dial OK! login OK! PPP ON awfulhak> .Ed
p If the
a /etc/ppp/ppp.linkup file is available, its contents are executed when the .Em PPP connection is established. See the provided .Dq pmdemand example in
a /etc/ppp/ppp.conf.sample which adds a default route. The strings .Dv HISADDR , .Dv MYADDR and .Dv INTERFACE are available as the relevent IP addresses and interface name. Similarly, when a connection is closed, the contents of the
a /etc/ppp/ppp.linkdown file are executed. Both of these files have the same format as
a /etc/ppp/ppp.conf . .Sh BACKGROUND DIALING If you want to establish a connection using .Nm non-interactively (such as from a .Xr crontab 5 entry or an .Xr at 1 job) you should use the .Fl background option. You must also specify the destination label in
a /etc/ppp/ppp.conf to use. This label must contain the .Dq set ifaddr command to define the remote peers IP address. (refer to
a /etc/ppp/ppp.conf.sample ) When .Fl background is specified, .Nm attempts to establish the connection immediately. If multiple phone numbers are specified, each phone number will be tried once. If the attempt fails, .Nm exits immediately with a non-zero exit code. If it succeeds, then .Nm becomes a daemon, and returns an exit status of zero to its caller. The daemon exits automatically if the connection is dropped by the remote system, or it receives a .Dv TERM signal. .Sh DIAL ON DEMAND Demand dialing is enabled with the .Fl auto or .Fl ddial options. You must also specify the destination label in
a /etc/ppp/ppp.conf to use. It must contain the .Dq set ifaddr command to define the remote peers IP address. (refer to
a /etc/ppp/ppp.conf.sample ) d -literal -offset indent # ppp -auto pmdemand ... # .Ed
p When .Fl auto or .Fl ddial is specified, .Nm runs as a daemon but you can still configure or examine its configuration by using the diagnostic port as follows (this can be done in .Fl background and .Fl direct mode too): d -literal -offset indent # pppctl -v 3000 show ipcp Password: IPCP [Opened] his side: xxxx .... .Ed
p Currently, .Xr telnet 1 may also be used to talk interactively.
p In order to achieve this, you must use the .Dq set server command as described below. It is possible to retrospectively make a running .Nm program listen on a diagnostic port by configuring
a /etc/ppp/ppp.secret , and sending it a .Dv USR1 signal. In .Fl auto mode, when an outgoing packet is detected, .Nm will perform the dialing action (chat script) and try to connect with the peer. In .Fl ddial mode, the dialing action is performed any time the line is found to be down. If the connect fails, the default behaviour is to wait 30 seconds and then attempt to connect when another outgoing packet is detected. This behaviour can be changed with d -literal -offset indent set redial seconds|random[.nseconds|random] [dial_attempts] .Ed
p .Sq Seconds is the number of seconds to wait before attempting to connect again. If the argument is .Sq random , the delay period is a random value between 0 and 30 seconds. .Sq Nseconds is the number of seconds to wait before attempting to dial the next number in a list of numbers (see the .Dq set phone command). The default is 3 seconds. Again, if the argument is .Sq random , the delay period is a random value between 0 and 30 seconds. .Sq dial_attempts is the number of times to try to connect for each outgoing packet that is received. The previous value is unchanged if this parameter is omitted. If a value of zero is specified for .Sq dial_attempts , .Nm will keep trying until a connection is made. d -literal -offset indent set redial 10.3 4 .Ed
p will attempt to connect 4 times for each outgoing packet that is detected with a 3 second delay between each number and a 10 second delay after all numbers have been tried. If multiple phone numbers are specified, the total number of attempts is still 4 (it does not attempt each number 4 times). Modifying the dial delay is very useful when running .Nm in demand dial mode on both ends of the link. If each end has the same timeout, both ends wind up calling each other at the same time if the link drops and both ends have packets queued. At some locations, the serial link may not be reliable, and carrier may be lost at inappropriate times. It is possible to have .Nm redial should carrier be unexpectedly lost during a session. d -literal -offset indent set reconnect timeout ntries .Ed
p This command tells .Nm to re-establish the connection .Ar ntries times on loss of carrier with a pause of .Ar timeout seconds before each try. For example, d -literal -offset indent set reconnect 3 5 .Ed
p tells .Nm that on an unexpected loss of carrier, it should wait .Ar 3 seconds before attempting to reconnect. This may happen up to .Ar 5 times before .Nm gives up. The default value of ntries is zero (no reconnect). Care should be taken with this option. If the local timeout is slightly longer than the remote timeout, the reconnect feature will always be triggered (up to the given number of times) after the remote side times out and hangs up. NOTE: In this context, losing too many LQRs constitutes a loss of carrier and will trigger a reconnect. If the .Fl background flag is specified, all phone numbers are dialed at most once until a connection is made. The next number redial period specified with the .Dq set redial command is honoured, as is the reconnect tries value. If your redial value is less than the number of phone numbers specified, not all the specified numbers will be tried. To terminate the program, type PPP ON awfulhak> close ppp ON awfulhak> quit all
p A simple .Dq quit command will terminate the .Xr pppctl 8 or .Xr telnet 1 connection but not the .Nm program itself. You must use .Dq quit all to terminate .Nm as well. .Sh RECEIVING INCOMING PPP CONNECTIONS (Method 1) To handle an incoming .Em PPP connection request, follow these steps: l -enum t Make sure the modem and (optionally)
a /etc/rc.serial is configured correctly. l -bullet -compact t Use Hardware Handshake (CTS/RTS) for flow control. t Modem should be set to NO echo back (ATE0) and NO results string (ATQ1). .El
p t Edit
a /etc/ttys to enable a .Xr getty 8 on the port where the modem is attached. For example: .Dl ttyd1 "/usr/libexec/getty std.38400" dialup on secure Don't forget to send a .Dv HUP signal to the .Xr init 8 process to start the .Xr getty 8 . .Dl # kill -HUP 1 t Prepare an account for the incoming user. d -literal ppp:xxxx:66:66:PPP Login User:/home/ppp:/usr/local/bin/ppplogin .Ed
p t Create a
a /usr/local/bin/ppplogin file with the following contents: d -literal -offset indent #!/bin/sh -p exec /usr/sbin/ppp -direct .Ed
p (You can specify a label name for further control.)
p Direct mode
q Fl direct lets .Nm work with stdin and stdout. You can also use .Xr pppctl 8 or .Xr telnet 1 to connect to a configured diagnostic port, in the same manner as with client-side .Nm ppp . t Optional support for Microsoft's IPCP Name Server and NetBIOS Name Server negotiation can be enabled use .Dq enable msext and .Dq set ns pri-addr [sec-addr] along with .Dq set nbns pri-addr [sec-addr] in your
p .Sh RECEIVING INCOMING PPP CONNECTIONS (Method 2) This method differs in that it recommends the use of .Em mgetty+sendfax to handle the modem connections. The latest versions (0.99 and higher) can be compiled with the .Dq AUTO_PPP option to allow detection of clients speaking .Em PPP to the login prompt. Follow these steps: l -enum t Get, configure, and install mgetty+sendfax v0.99 or later making sure you have used the AUTO_PPP option. t Edit
a /etc/ttys to enable a mgetty on the port where the modem is attached. For example: .Dl cuaa1 "/usr/local/sbin/mgetty -s 57600" dialup on t Prepare an account for the incoming user. d -literal Pfred:xxxx:66:66:Fred's PPP:/home/ppp:/etc/ppp/ppp-dialup .Ed
p t Examine the files
a /etc/ppp/sample.ppp-dialup ,
a /etc/ppp/sample.ppp-pap-dialup and
a /etc/ppp/ppp.conf.sample for ideas.
a /etc/ppp/ppp-pap-dialup is supposed to be called from
a /usr/local/etc/mgetty+sendfax/login.conf from a line like .Dl /AutoPPP/ - - /etc/ppp/ppp-pap-dialup .El
p .Sh PPP OVER TCP (a.k.a Tunneling) Instead of running .Nm over a serial link, it is possible to use a TCP connection instead by specifying a host and port as the device: .Dl set device ui-gate:6669 Instead of opening a serial device, .Nm will open a TCP connection to the given machine on the given socket. It should be noted however that .Nm doesn't use the telnet protocol and will be unable to negotiate with a telnet server. You should set up a port for receiving this .Em PPP connection on the receiving machine (ui-gate). This is done by first updating
a /etc/services to name the service: .Dl ppp-in 6669/tcp # Incoming PPP connections over TCP and updating
a /etc/inetd.conf to tell .Xr inetd 8 how to deal with incoming connections on that port: .Dl ppp-in stream tcp nowait root /usr/sbin/ppp ppp -direct ppp-in Don't forget to send a .Dv HUP signal to .Xr inetd 8 after you've updated
a /etc/inetd.conf . Here, we use a label named .Dq ppp-in . The entry in
a /etc/ppp/ppp.conf on ui-gate (the receiver) should contain the following: d -literal -offset indent ppp-in: set timeout 0 set ifaddr 10.0.4.1 10.0.4.2 add 10.0.1.0 255.255.255.0 10.0.4.2 .Ed
p You may also want to enable PAP or CHAP for security. To enable PAP, add the following line: d -literal -offset indent enable PAP .Ed
p You'll also need to create the following entry in
a /etc/ppp/ppp.secret : d -literal -offset indent MyAuthName MyAuthPasswd .Ed
p The entry in
a /etc/ppp/ppp.conf on awfulhak (the initiator) should contain the following: d -literal -offset indent ui-gate: set escape 0xff set device ui-gate:ppp-in set dial set timeout 30 5 4 set log Phase Chat Connect Carrier hdlc LCP IPCP CCP tun set ifaddr 10.0.4.2 10.0.4.1 add 10.0.2.0 255.255.255.0 10.0.4.1 .Ed
p Again, if you're enabling PAP, you'll also need: d -literal -offset indent set authname MyAuthName set authkey MyAuthKey .Ed
p We're assigning the address of 10.0.4.1 to ui-gate, and the address 10.0.4.2 to awfulhak. To open the connection, just type .Dl awfulhak # ppp -background ui-gate The result will be an additional "route" on awfulhak to the 10.0.2.0/24 network via the TCP connection, and an additional "route" on ui-gate to the 10.0.1.0/24 network. The networks are effectively bridged - the underlying TCP connection may be across a public network (such as the Internet), and the .Em PPP traffic is conceptually encapsulated (although not packet by packet) inside the TCP stream between the two gateways. The major disadvantage of this mechanism is that there are two "guaranteed delivery" mechanisms in place - the underlying TCP stream and whatever protocol is used over the .Em PPP link - probably TCP again. If packets are lost, both levels will get in each others way trying to negotiate sending of the missing packet. .Sh PACKET ALIASING The .Fl alias command line option enables packet aliasing. This allows the .Nm host to act as a masquerading gateway for other computers over a local area network. Outgoing IP packets are aliased so that they appear to come from the .Nm host, and incoming packets are de-aliased so that they are routed to the correct machine on the local area network. Packet aliasing allows computers on private, unregistered subnets to have Internet access, although they are invisible from the outside world. In general, correct .Nm operation should first be verified with packet aliasing disabled. Then, the .Fl alias option should be switched on, and network applications (web browser, .Xr telnet 1 , .Xr ftp 1 , .Xr ping 8 , .Xr traceroute 8 ) should be checked on the .Nm host. Finally, the same or similar applications should be checked on other computers in the LAN. If network applications work correctly on the .Nm host, but not on other machines in the LAN, then the masquerading software is working properly, but the host is either not forwarding or possibly receiving IP packets. Check that IP forwarding is enabled in
a /etc/rc.conf and that other machines have designated the .Nm host as the gateway for the LAN. .Sh PACKET FILTERING This implementation supports packet filtering. There are four kinds of filters; ifilter, ofilter, dfilter and afilter. Here are the basics: l -bullet -compact t A filter definition has the following syntax: set filter-name rule-no action [src_addr/src_width] [dst_addr/dst_width] [proto [src [lt|eq|gt] port ]] [dst [lt|eq|gt] port] [estab] l -enum t .Sq filter-name should be one of ifilter, ofilter, dfilter or afilter. t There are two actions: .Sq permit and .Sq deny . If a given packet matches the rule, the associated action is taken immediately. t .Sq src_width and .Sq dst_width work like a netmask to represent an address range. t .Sq proto must be one of icmp, udp or tcp. t .Sq port number can be specified by number and service name from
p t Each filter can hold up to 20 rules, starting from rule 0. The entire rule set is not effective until rule 0 is defined, ie. the default is to allow everything through. t If no rule is matched to a packet, that packet will be discarded (blocked). t Use .Dq set filter-name -1 to flush all rules. .El
p See
a /etc/ppp/ppp.conf.filter.example . .Sh SETTING IDLE, LINE QUALITY REQUEST, RETRY TIMER To check/set idle timer, use the .Dq show timeout and .Dq set timeout [lqrtimer [retrytimer]] commands: d -literal -offset indent ppp ON awfulhak> set timeout 600 .Ed
p The timeout period is measured in seconds, the default values for which are timeout = 180 or 3 min, lqrtimer = 30sec and retrytimer = 3sec. To disable the idle timer function, use the command d -literal -offset indent ppp ON awfulhak> set timeout 0 .Ed
p In .Fl auto mode, an idle timeout causes the .Em PPP session to be closed, though the .Nm program itself remains running. Another trigger packet will cause it to attempt to reestablish the link. .Sh PREDICTOR-1 COMPRESSION This version supports CCP and Predictor type 1 compression based on the current IETF-draft specs. As a default behaviour, .Nm will attempt to use (or be willing to accept) this capability when the peer agrees (or requests it). To disable CCP/predictor1 functionality completely, use the .Dq disable pred1 and .Dq deny pred1 commands. .Sh CONTROLLING IP ADDRESS .Nm uses IPCP to negotiate IP addresses. Each side of the connection specifies the IP address that it's willing to use, and if the requested IP address is acceptable then .Nm returns ACK to the requester. Otherwise, .Nm returns NAK to suggest that the peer use a different IP address. When both sides of the connection agree to accept the received request (and send ACK), IPCP is set to the open state and a network level connection is established. To control this IPCP behaviour, this implementation has the .Dq set ifaddr command for defining the local and remote IP address: d -literal -offset indent set ifaddr [src_addr [dst_addr [netmask [trigger_addr]]]] .Ed
p where, .Sq src_addr is the IP address that the local side is willing to use, .Sq dst_addr is the IP address which the remote side should use and .Sq netmask is the netmask that should be used. .Sq Src_addr and .Sq dst_addr default to 0.0.0.0, and .Sq netmask defaults to whatever mask is appropriate for .Sq src_addr . It is only possible to make .Sq netmask smaller than the default. The usual value is 255.255.255.255. Some incorrect .Em PPP implementations require that the peer negotiates a specific IP address instead of .Sq src_addr . If this is the case, .Sq trigger_addr may be used to specify this IP number. This will not affect the routing table unless the other side agrees with this proposed number. d -literal -offset indent set ifaddr 192.244.177.38 192.244.177.2 255.255.255.255 0.0.0.0 .Ed
p The above specification means: l -bullet -compact t I will first suggest that my IP address should be 0.0.0.0, but I will only accept an address of 192.244.177.38. t I strongly insist that the peer uses 192.244.177.2 as his own address and won't permit the use of any IP address but 192.244.177.2. When the peer requests another IP address, I will always suggest that it uses 192.244.177.2. t The routing table entry will have a netmask of 0xffffffff. .El
p This is all fine when each side has a pre-determined IP address, however it is often the case that one side is acting as a server which controls all IP addresses and the other side should obey the direction from it. In order to allow more flexible behaviour, `ifaddr' variable allows the user to specify IP address more loosely: .Dl set ifaddr 192.244.177.38/24 192.244.177.2/20 A number followed by a slash (/) represent the number of bits significant in the IP address. The above example signifies that: l -bullet -compact t I'd like to use 192.244.177.38 as my address if it is possible, but I'll also accept any IP address between 192.244.177.0 and 192.244.177.255. t I'd like to make him use 192.244.177.2 as his own address, but I'll also permit him to use any IP address between 192.244.176.0 and 192.244.191.255. t As you may have already noticed, 192.244.177.2 is equivalent to saying 192.244.177.2/32. t As an exception, 0 is equivalent to 0.0.0.0/0, meaning that I have no preferred IP address and will obey the remote peers selection. When using zero, no routing table entries will be made until a connection is established. t 192.244.177.2/0 means that I'll accept/permit any IP address but I'll try to insist that 192.244.177.2 be used first. .El
p .Sh CONNECTING WITH YOUR INTERNET SERVICE PROVIDER The following steps should be taken when connecting to your ISP: l -enum t Describe your providers phone number(s) in the dial script using the .Dq set phone command. This command allows you to set multiple phone numbers for dialing and redialing separated by either a pipe (|) or a colon (:) d -literal -offset indent set phone "111[|222]...[:333[|444]...]... .Ed
p Numbers after the first in a pipe-separated list are only used if the previous number was used in a failed dial or login script. Numbers separated by a colon are used sequentially, irrespective of what happened as a result of using the previous number. For example: d -literal -offset indent set phone "1234567|2345678:3456789|4567890" .Ed
p Here, the 1234567 number is attempted. If the dial or login script fails, the 2345678 number is used next time, but *only* if the dial or login script fails. On the dial after this, the 3456789 number is used. The 4567890 number is only used if the dial or login script using the 3456789 fails. If the login script of the 2345678 number fails, the next number is still the 3456789 number. As many pipes and colons can be used as are necessary (although a given site would usually prefer to use either the pipe or the colon, but not both). The next number redial timeout is used between all numbers. When the end of the list is reached, the normal redial period is used before starting at the beginning again. The selected phone number is substituted for the \\\\T string in the .Dq set dial command (see below). t Set up your redial requirements using .Dq set redial . For example, if you have a bad telephone line or your provider is usually engaged (not so common these days), you may want to specify the following: d -literal -offset indent set redial 10 4 .Ed
p This says that up to 4 phone calls should be attempted with a pause of 10 seconds before dialing the first number again. t Describe your login procedure using the .Dq set dial and .Dq set login commands. The .Dq set dial command is used to talk to your modem and establish a link with your ISP, for example: d -literal -offset indent set dial "ABORT BUSY ABORT NO\\\\sCARRIER TIMEOUT 4 \\"\\" \e ATZ OK-ATZ-OK ATDT\\\\T TIMEOUT 60 CONNECT" .Ed
p This modem "chat" string means: l -bullet t Abort if the string "BUSY" or "NO CARRIER" are received. t Set the timeout to 4 seconds. t Expect nothing. t Send ATZ. t Expect OK. If that's not received within the 4 second timeout, send ATZ and expect OK. t Send ATDTxxxxxxx where xxxxxxx is the next number in the phone list from above. t Set the timeout to 60. t Wait for the CONNECT string. .El
p Once the connection is established, the login script is executed. This script is written in the same style as the dial script, but care should be taken to avoid having your password logged: d -literal -offset indent set authkey MySecret set login "TIMEOUT 15 login:-\\\\r-login: awfulhak \e word: \\\\P ocol: PPP HELLO" .Ed
p This login "chat" string means: l -bullet t Set the timeout to 15 seconds. t Expect "login:". If it's not received, send a carriage return and expect "login:" again. t Send "awfulhak" t Expect "word:" (the tail end of a "Password:" prompt). t Send whatever our current .Ar authkey value is set to. t Expect "ocol:" (the tail end of a "Protocol:" prompt). t Send "PPP". t Expect "HELLO". .El
p The .Dq set authkey command is logged specially (when using .Ar command logging) so that the actual password is not compromised (it is logged as .Sq ******** Ns ), and the '\\P' is logged when .Ar chat logging is active rather than the actual password.
p Login scripts vary greatly between ISPs. t Use .Dq set line and .Dq set speed to specify your serial line and speed, for example: d -literal -offset indent set line /dev/cuaa0 set speed 115200 .Ed
p Cuaa0 is the first serial port on FreeBSD. If you're running .Nm on OpenBSD, cua00 is the first. A speed of 115200 should be specified if you have a modem capable of bit rates of 28800 or more. In general, the serial speed should be about four times the modem speed. t Use the .Dq set ifaddr command to define the IP address. l -bullet t If you know what IP address your provider uses, then use it as the remote address (dst_addr), otherwise choose something like 10.0.0.2/0 (see below). t If your provider has assigned a particular IP address to you, then use it as your address (src_addr). t If your provider assigns your address dynamically, choose a suitably unobtrusive and unspecific IP number as your address. 10.0.0.1/0 would be appropriate. The bit after the / specifies how many bits of the address you consider to be important, so if you wanted to insist on something in the class C network 1.2.3.0, you could specify 1.2.3.1/24. t If you find that your ISP accepts the first IP number that you suggest, specify third and forth arguments of .Dq 0.0.0.0 . This will force your ISP to assign a number. (The third argument will be ignored as it is less restrictive than the default mask for your .Sq src_addr . .El
p An example for a connection where you don't know your IP number or your ISPs IP number would be: d -literal -offset indent set ifaddr 10.10.10.10/0 10.10.11.11/0 0.0.0.0 0.0.0.0 .Ed
p t In most cases, your ISP will also be your default router. If this is the case, and if you're using .Fl auto mode, add the lines d -literal -offset indent delete ALL add default HISADDR .Ed
p to
p This tells .Nm to delete all non-direct routing entries for the tun interface that .Nm is running on, then to add a default route to 10.10.11.11. If you're not using .Fl auto mode, this isn't necessary as .Nm will dial immediately and may negotiate new IP numbers with the peer.
p If you're not using .Fl auto mode, or if you're using dynamic IP numbers, you must also put these two lines in the
a /etc/ppp/ppp.linkup file: d -literal -offset indent delete ALL add default HISADDR .Ed
p HISADDR is a macro meaning the "other side"s IP number, and is available once an IP number has been agreed (using IPCP) or set
q using Dq set ifaddr . Now, once a connection is established, .Nm will delete all non-direct interface routes, and add a default route pointing at the peers IP number. You should use the same label as the one used in
p If commands are being typed interactively, the only requirement is to type d -literal -offset indent add default HISADDR .Ed
p after a successful dial. t If your provider requests that you use PAP/CHAP authentication methods, add the next lines to your
a /etc/ppp/ppp.conf file: d -literal -offset indent set authname MyName set authkey MyPassword .Ed
p Both are accepted by default, so .Nm will provide whatever your ISP requires. .El
p Please refer to
a /etc/ppp/ppp.conf.sample and
a /etc/ppp/ppp.linkup.sample for some real examples. The pmdemand label should be appropriate for most ISPs. .Sh LOGGING FACILITY .Nm is able to generate the following log info either via .Xr syslog 3 or directly to the screen: l -column SMMMMMM -offset indent t Li Async Dump async level packet in hex t Li Carrier Log Chat lines with 'CARRIER' t Li CCP Generate a CCP packet trace t Li Chat Generate Chat script trace log t Li Command Log commands executed t Li Connect Generate complete Chat log t Li Debug Log (very verbose) debug information t Li HDLC Dump HDLC packet in hex t Li ID0 Log all function calls specifically made as user id 0. t Li IPCP Generate an IPCP packet trace t Li LCP Generate an LCP packet trace t Li Link Log address assignments and link up/down events t Li LQM Generate LQR report t Li Phase Phase transition log output t Li TCP/IP Dump all TCP/IP packets t Li TUN Include the tun device on each log line t Li Warning Output to the terminal device. If there is currently no terminal, output is sent to the log file using LOG_WARNING. t Li Error Output to both the terminal device and the log file using LOG_ERROR. t Li Alert Output to the log file using LOG_ALERT .El
p The .Dq set log command allows you to set the logging output level. Multiple levels can be specified on a single command line. The default is equivalent to .Dq set log Carrier Link Phase .
p It is also possible to log directly to the screen. The syntax is the same except that the word .Dq local should immediately follow .Dq set log . The default is .Dq set log local (ie. no direct screen logging).
p If The first argument to .Dq set log Op local begins with a '+' or a '-' character, the current log levels are not cleared, for example: d -literal -offset indent PPP ON awfulhak> set log carrier link phase PPP ON awfulhak> show log Log: Carrier Link Phase Warning Error Alert Local: Warning Error Alert PPP ON awfulhak> set log -link +tcp/ip -warning PPP ON awfulhak> set log local +command PPP ON awfulhak> show log Log: Carrier Phase TCP/IP Warning Error Alert Local: Command Warning Error Alert .Ed
p Log messages of level Warning, Error and Alert are not controllable using .Dq set log Op local .
p The .Ar Warning level is special in that it will not be logged if it can be displayed locally. .Sh SIGNAL HANDLING .Nm Ppp deals with the following signals: l -tag -width 20 t INT Receipt of this signal causes the termination of the current connection (if any). This will cause .Nm to exit unless it is in .Fl auto or .Fl ddial mode. t HUP, TERM & QUIT These signals tell .Nm to exit. t USR1 This signal, when not in interactive mode, tells .Nm to close any existing server socket and open an Internet socket using port 3000 plus the current tunnel device number. This can only be achieved if a suitable local password is specified in
a /etc/ppp/ppp.secret . t USR2 This signal, tells .Nm to close any existing server socket. .El
p .Sh PPP COMMAND LIST This section lists the available commands and their effect. They are usable either from an interactive .Nm session, from a configuration file or from a .Xr pppctl 8 or .Xr telnet 1 session. l -tag -width 20 t accept|deny|enable|disable option.... These directives tell .Nm how to negotiate the initial connection with the peer. Each .Dq option has a default of either accept or deny and enable or disable. .Dq Accept means that the option will be ACK'd if the peer asks for it. .Dq Deny means that the option will be NAK'd if the peer asks for it. .Dq Enable means that the option will be requested by us. .Dq Disable means that the option will not be requested by us.
p .Dq Option may be one of the following: l -tag -width 20 t acfcomp Default: Enabled and Accepted. ACFComp stands for Address and Control Field Compression. Non LCP packets usually have very similar address and control fields - making them easily compressible. t chap Default: Disabled and Accepted. CHAP stands for Challenge Handshake Authentication Protocol. Only one of CHAP and PAP (below) may be negotiated. With CHAP, the authenticator sends a "challenge" message to its peer. The peer uses a one-way hash function to encrypt the challenge and sends the result back. The authenticator does the same, and compares the results. The advantage of this mechanism is that no passwords are sent across the connection. A challenge is made when the connection is first made. Subsequent challenges may occur. If you want to have your peer authenticate itself, you must .Dq enable chap . in
a /etc/ppp/ppp.conf , and have an entry in
a /etc/ppp/ppp.secret for the peer.
p When using CHAP as the client, you need only specify .Dq AuthName and .Dq AuthKey in
a /etc/ppp/ppp.conf . CHAP is accepted by default. Some .Em PPP implementations use "MS-CHAP" rather than MD5 when encrypting the challenge. Refer to the description of the .Dq set encrypt command for further details. t deflate Default: Enabled and Accepted. This option decides if deflate compression will be used by the Compression Control Protocol (CCP). This is the same algorithm as used by the .Xr gzip 1 program. Note: There is a problem negotiating .Ar deflate capabilities with .Xr pppd 8 - a .Em PPP implementation available under many operating systems. .Nm Pppd (version 2.3.1) incorrectly attempts to negotiate .Ar deflate compression using type .Em 24 as the CCP configuration type rather than type .Em 26 as specified in
a rfc1979 . Type .Ar 24 is actually specified as .Dq PPP Magnalink Variable Resource Compression in
a rfc1975 Ns No ! .Nm Ppp is capable of negotiating with .Nm pppd , but only if .Dq pppd-deflate is .Ar enable Ns No d and .Ar accept Ns No ed . t lqr Default: Disabled and Accepted. This option decides if Link Quality Requests will be sent. LQR is a protocol that allows .Nm to determine that the link is down without relying on the modems carrier detect. t pap Default: Disabled and Accepted. PAP stands for Password Authentication Protocol. Only one of PAP and CHAP (above) may be negotiated. With PAP, the ID and Password are sent repeatedly to the peer until authentication is acknowledged or the connection is terminated. This is a rather poor security mechanism. It is only performed when the connection is first established. If you want to have your peer authenticate itself, you must .Dq enable pap . in
a /etc/ppp/ppp.conf , and have an entry in
a /etc/ppp/ppp.secret for the peer (although see the .Dq passwdauth option below).
p When using PAP as the client, you need only specify .Dq AuthName and .Dq AuthKey in
a /etc/ppp/ppp.conf . PAP is accepted by default. t pppd-deflate Default: Disabled and Denied. This is a variance of the .Ar deflate option, allowing negotiation with the .Xr pppd 8 program. Refer to the .Ar deflate section above for details. It is disabled by default as it violates
a rfc1975 . t pred1 Default: Enabled and Accepted. This option decides if Predictor 1 compression will be used by the Compression Control Protocol (CCP). t protocomp Default: Enabled and Accepted. This option is used to negotiate PFC (Protocol Field Compression), a mechanism where the protocol field number is reduced to one octet rather than two. t vjcomp Default: Enabled and Accepted. This option decides if Van Jacobson header compression will be used. .El
p The following options are not actually negotiated with the peer. Therefore, accepting or denying them makes no sense. l -tag -width 20 t msext Default: Disabled. This option allows the use of Microsoft's .Em PPP extensions, supporting the negotiation of the DNS and the NetBIOS NS. Enabling this allows us to pass back the values given in "set ns" and "set nbns". t passwdauth Default: Disabled. Enabling this option will tell the PAP authentication code to use the password file (see .Xr passwd 5 ) to authenticate the caller rather than the
a /etc/ppp/ppp.secret file. t proxy Default: Disabled. Enabling this option will tell .Nm to proxy ARP for the peer. t throughput Default: Disabled. Enabling this option will tell .Nm to gather thoroughput statistics. Input and output is sampled over a rolling 5 second window, and current, best and total figures are retained. This data is output when the relevent .Em PPP layer shuts down, and is also available using the .Dq show command. Troughput statistics are available at the .Dq IPCP and .Dq modem levels. t utmp Default: Enabled. Normally, when a user is authenticated using PAP or CHAP, and when .Nm is running in .Fl direct mode, an entry is made in the utmp and wtmp files for that user. Disabling this option will tell .Nm not to make any utmp or wtmp entries. This is usually only necessary if you require the user to both login and authenticate themselves. .El
p t add[!] dest mask gateway .Ar Dest is the destination IP address and .Ar mask is its mask. .Ar 0 0 refers to the default route, and it is possible to use the symbolic name .Sq default in place of both the .Ar dest and .Ar mask arguments. .Ar Gateway is the next hop gateway to get to the given .Ar dest machine/network. It is possible to use the symbolic names .Sq HISADDR or .Sq INTERFACE as the .Ar gateway . .Sq INTERFACE is replaced with the current interface name and .Sq HISADDR is replaced with the current interface address. If the current interface address has not yet been assigned
q via Dq set ifaddr , the current .Sq INTERFACE is used instead.
p Refer to the .Dq set ifaddr command below for details of some restrictions regarding the use of this command in the
a ppp.conf file.
p If the .Ar add! command is used
q note the following Dq ! , then if the route already exists, it will be updated as with the .Sq route change command (see .Xr route 8 for further details). t allow ..... This command controls access to .Nm and its configuration files. It is possible to allow user-level access, depending on the configuration file label and on the mode that .Nm is being run in. For example, you may wish to configure .Nm so that only user .Sq fred may access label .Sq fredlabel in .Fl background mode.
p User id 0 is immune to these commands. l -tag -width 20 t allow user|users logname... By default, only user id 0 is allowed access. If this command is specified, all of the listed users are allowed access to the section in which the .Dq allow users command is found. The .Sq default section is always checked first (although it is only ever automatically loaded at startup). Each successive .Dq allow users command overrides the previous one, so it's possible to allow users access to everything except a given label by specifying default users in the .Sq default section, and then specifying a new user list for that label.
p If user .Sq * is specified, access is allowed to all users. t allow mode|modes modelist... By default, access using all .Nm modes is possible. If this command is used, it restricts the access modes allowed to load the label under which this command is specified. Again, as with the .Dq allow users command, each .Dq allow modes command overrides the previous, and the .Sq default section is always checked first.
p Possible modes are: .Sq interactive , .Sq auto , .Sq direct , .Sq dedicated , .Sq ddial , .Sq background and .Sq * . .El
p t alias ..... This command allows the control of the aliasing (or masquerading) facilities that are built into .Nm ppp . Until this code is required, it is not loaded by .Nm ppp , and it is quite possible that the alias library is not installed on your system (some administrators consider it a security risk). If aliasing is enabled on your system, the following commands are possible: l -tag -width 20 t alias enable [yes|no] This command either switches aliasing on or turns it off. The .Fl alias command line flag is synonymous with .Dq alias enable yes . t alias port [proto targetIP:targetPORT [aliasIP:]aliasPORT] This command allows us to redirect connections arriving at .Dq aliasPORT for machine [aliasIP] to .Dq targetPORT on .Dq targetIP . If proto is specified, only connections of the given protocol are matched. This option is useful if you wish to run things like Internet phone on the machines behind your gateway. t alias addr [addr_local addr_alias] This command allows data for .Dq addr_alias to be redirected to .Dq addr_local . It is useful if you own a small number of real IP numbers that you wish to map to specific machines behind your gateway. t alias deny_incoming [yes|no] If set to yes, this command will refuse all incoming connections by dropping the packets in much the same way as a firewall would. t alias log [yes|no] This option causes various aliasing statistics and information to be logged to the file
a /var/log/alias.log . t alias same_ports [yes|no] When enabled, this command will tell the alias library attempt to avoid changing the port number on outgoing packets. This is useful if you want to support protocols such as RPC and LPD which require connections to come from a well known port. t alias use_sockets [yes|no] When enabled, this option tells the alias library to create a socket so that it can guarantee a correct incoming ftp data or IRC connection. t alias unregistered_only [yes|no] Only alter outgoing packets with an unregistered source ad- dress. According to RFC 1918, unregistered source addresses are 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16. t alias help|? This command gives a summary of available alias commands. .El
p t [!]bg command The given command is executed in the background. Any of the pseudo arguments .Dv HISADDR , .Dv INTERFACE and .Dv MYADDR will be replaced with the appropriate values. If you wish to pause .Nm while the command executes, use the .Dv shell command instead. t close Close the current connection (but don't quit). t delete[!] dest This command deletes the route with the given .Ar dest IP address. If .Ar dest is specified as .Sq ALL , all non-direct entries in the routing for the current interface that .Nm is using are deleted. This means all entries for tunN, except the entry representing the actual link. If .Ar dest is specified as .Sq default , the default route is deleted.
p If the .Ar delete! command is used
q note the following Dq ! , .Nm will not complain if the route does not already exist. t dial|call [remote] If .Dq remote is specified, a connection is established using the .Dq dial and .Dq login scripts for the given .Dq remote system. Otherwise, the current settings are used to establish the connection. t display Displays the current status of the negotiable protocol values as specified under .Dq accept|deny|enable|disable option.... above. t down Bring the link down ungracefully, as if the physical layer had become unavailable. It's not considered polite to use this command. t help|? [command] Show a list of available commands. If .Dq command is specified, show the usage string for that command. t load [remote] Load the given .Dq remote label. If .Dq remote is not given, the .Dq default label is assumed. t passwd pass Specify the password required for access to the full .Nm command set. This password is required when connecting to the diagnostic port (see the .Dq set server command). .Ar Pass may be specified either on the .Dq set server command line or by putting an entry in
a /var/log/ppp.secret for the local host. The value of .Ar pass is not logged when .Ar command logging is active, instead, the literal string .Dq ******** is logged. t quit|bye [all] Exit .Nm ppp . If .Nm is in interactive mode or if the .Dq all argument is given, .Nm will exit, closing the connection. A simple .Dq quit issued from a .Xr pppctl 8 or .Xr telnet 1 session will not close the current connection. t save This option is not (yet) implemented. t set[up] var value This option allows the setting of any of the following variables: l -tag -width 20 t set accmap hex-value ACCMap stands for Asyncronous Control Character Map. This is always negotiated with the peer, and defaults to a value of 0x00000000. This protocol is required to defeat hardware that depends on passing certain characters from end to end (such as XON/XOFF etc). t set filter-name rule-no action [src_addr/src_width] [dst_addr/dst_width] [proto [src [lt|eq|gt] port ]] [dst [lt|eq|gt] port] [estab]
p .Nm Ppp supports four filter sets. The afilter specifies packets that keep the connection alive - reseting the idle timer. The dfilter specifies packets that cause .Nm to dial when in .Fl auto mode. The ifilter specifies packets that are allowed to travel into the machine and the ofilter specifies packets that are allowed out of the machine. By default all filter sets allow all packets to pass. Rules are processed in order according to .Dq n . Up to 20 rules may be given for each set. If a packet doesn't match any of the rules in a given set, it is discarded. In the case of ifilters and ofilters, this means that the packet is dropped. In the case of afilters it means that the packet will not reset the idle timer and in the case of dfilters it means that the packet will not trigger a dial. Refer to the section on PACKET FILTERING above for further details. t set authkey|key value This sets the authentication key (or password) used in client mode PAP or CHAP negotiation to the given value. It can also be used to specify the password to be used in the dial or login scripts in place of the '\\P' sequence, preventing the actual password from being logged. If .Ar command logging is in effect, .Ar value is logged as .Ar ******** for security reasons. t set authname id This sets the authentication id used in client mode PAP or CHAP negotiation. t set ctsrts This sets hardware flow control and is the default. t set device|line value[,value...] This sets the device(s) to which .Nm will talk to the given .Dq value . All serial device names are expected to begin with
a /dev/ . If .Dq value does not begin with
a /dev/ , it must be of the format .Dq host:port . If this is the case, .Nm will attempt to connect to the given .Dq host on the given .Dq port . Refer to the section on .Em PPP OVER TCP above for further details. If multiple .Dq values are specified, .Nm will attempt to open each one in turn until it succeeds or runs out of devices. t set dial chat-script This specifies the chat script that will be used to dial the other side. See also the .Dq set login command below. Refer to .Xr chat 8 and to the example configuration files for details of the chat script format. It is possible to specify some special .Sq values in your chat script as follows: d -literal -offset indent t \\\\\\\\\\\\\\\\c When used as the last character in a .Sq send string, this indicates that a newline should not be appended. t \\\\\\\\\\\\\\\\d When the chat script encounters this sequence, it delays two seconds. t \\\\\\\\\\\\\\\\p When the chat script encounters this sequence, it delays for one quarter of a second. t \\\\\\\\\\\\\\\\n This is replaced with a newline character. t \\\\\\\\\\\\\\\\r This is replaced with a carriage return character. t \\\\\\\\\\\\\\\\s This is replaced with a space character. t \\\\\\\\\\\\\\\\t This is replaced with a tab character. t \\\\\\\\\\\\\\\\T This is replaced by the current phone number (see .Dq set phone below). t \\\\\\\\\\\\\\\\P This is replaced by the current .Ar authkey value (see .Dq set authkey above). t \\\\\\\\\\\\\\\\U This is replaced by the current .Ar authname value (see .Dq set authname above). .Ed
p Note that two parsers will examine these escape sequences, so in order to have the .Sq chat parser see the escape character, it is necessary to escape it from the .Sq command parser . This means that in practice you should use two escapes, for example: d -literal -offset indent set dial "... ATDT\\\\T CONNECT" .Ed
p It is also possible to execute external commands from the chat script. To do this, the first character of the expect or send string is an exclaimation mark
q Dq ! . When the command is executed, standard input and standard output are directed to the modem device (see the .Dq set device command), and standard error is read by .Nm and substituted as the expect or send string. If .Nm is running in interactive mode, file descriptor 4 is attached to
p For example (wrapped for readability); d -literal -offset indent set login "TIMEOUT 5 \\"\\" \\"\\" login:--login: ppp \e word: ppp \\"!sh \\\\\\\-c \\\\\\"echo \\\\\\\-n label: >&2\\\\\\"\\" \e \\"!/bin/echo in\\" HELLO" .Ed
p would result in the following chat sequence (output using the .Sq set log local chat command before dialing): d -literal -offset indent Dial attempt 1 of 1 dial OK! Chat: Expecting: Chat: Sending: Chat: Expecting: login:--login: Chat: Wait for (5): login: Chat: Sending: ppp Chat: Expecting: word: Chat: Wait for (5): word: Chat: Sending: ppp Chat: Expecting: !sh \-c "echo \-n label: >&2" Chat: Exec: sh -c "echo -n label: >&2" Chat: Wait for (5): !sh \-c "echo \-n label: >&2" --> label: Chat: Exec: /bin/echo in Chat: Sending: Chat: Expecting: HELLO Chat: Wait for (5): HELLO login OK! .Ed
p Note (again) the use of the escape character, allowing many levels of nesting. Here, there are four parsers at work. The first parses the original line, reading it as three arguments. The second parses the third argument, reading it as 11 arguments. At this point, it is important that the .Dq - signs are escaped, otherwise this parser will see them as constituting an expect-send-expect sequence. When the .Dq ! character is seen, the execution parser reads the first command as three arguments, and then .Xr sh 1 itself expands the argument after the .Fl c . As we wish to send the output back to the modem, in the first example we redirect our output to file descriptor 2 (stderr) so that .Nm itself sends and logs it, and in the second example, we just output to stdout, which is attached directly to the modem.
p This, of course means that it is possible to execute an entirely external .Dq chat command rather than using the internal one. See .Xr chat 8 for a good alternative.
p t set hangup chat-script This specifies the chat script that will be used to reset the modem before it is closed. It should not normally be necessary, but can be used for devices that fail to reset themselves properly on close. t set encrypt MSChap|MD5 This specifies the encryption algorithm to request and use when issuing the CHAP challenge, and defaults to MD5. If this is set to MSChap, .Nm will behave like a Microsoft RAS when sending the CHAP challenge (assuming CHAP is enabled). When responding to a challenge, .Nm determines how to encrypt the response based on the challenge, so this setting is ignored. l -tag -width NOTE: t NOTE: Because the Microsoft encryption algorithm uses a combination of MD4 and DES, if you have not installed DES encryption software on your machine before building .Nm ppp , this option will not be available - only MD5 will be used. .El
p t set escape value... This option is similar to the .Dq set accmap option above. It allows the user to specify a set of characters that will be `escaped' as they travel across the link. t set ifaddr [myaddr [hisaddr [netmask [triggeraddr]]]] This command specifies the IP addresses that will be used during IPCP negotiation. Addresses are specified using the format .Dl a.b.c.d/n Where a.b.c.d is the preferred IP, but n specifies how many bits of the address we will insist on. If the /n bit is omitted, it defaults to /32 unless the IP address is 0.0.0.0 in which case the mask defaults to /0.
p .Ar Hisaddr may also be specified as a range of IP numbers in the format .Dl a.b.c.d[-d.e.f.g][,h.i.j.k[-l,m,n,o]]... for example: .Dl set ifaddr 10.0.0.1 10.0.1.2-10.0.1.10,10.0.1.20 will only negotiate .Ar 10.0.0.1 as the local IP number, but will assign any of the given 10 IP numbers to the peer. If the peer requests one of these numbers, and that number is not already in use, .Nm will grant the peers request. This is useful if the peer wants to re-establish a link using the same IP number as was previously allocated. If the peer requests an IP number that's either outside of this range or is already in use, .Nm will start by suggesting a random unused IP number from the range. If the peer doesn't subsequently agree, .Nm will suggest each of the other numbers in succession until a number is chosen or until too many IPCP Configure Requests have been sent.
p If .Ar triggeraddr is specified, it is used in place of .Ar myaddr in the initial IPCP negotiation. However, only an address in the .Ar myaddr range will be accepted.
p It should be noted that in .Fl auto mode, .Nm will configure the interface immediately upon reading the .Dq set ifaddr line in the config file. In any other mode, these values are just used for the IPCP negotiations, and the interface isn't configured until the IPCP layer is up. As a result, it is impossible
q or at least unwise to use the .Dq add command in
a ppp.conf unless using .Fl auto mode (the
a ppp.linkup file should be used instead). Use .Dq allow mode auto to restrict the current profile to .Fl auto mode only. t set loopback on|off When set to .Ar on (the default), .Nm will automatically loop back packets being sent out with a destination address equal to that of the .Em PPP interface. If set to .Ar off , .Nm will send the packet, probably resulting in an ICMP redirect from the other end. t set log [local] [+|-]value... This command allows the adjustment of the current log level. Refer to the Logging Facility section for further details. t set login chat-script This .Ar chat-script compliments the dial-script. If both are specified, the login script will be executed after the dial script. Escape sequences available in the dial script are also available here. t set mru value The default MRU is 1500. If it is increased, the other side *may* increase its mtu. There is no use decreasing the MRU to below the default as the .Em PPP protocol *must* be able to accept packets of at least 1500 octets. t set mtu value The default MTU is 1500. This may be increased by the MRU specified by the peer. It may only be subsequently decreased by this option. Increasing it is not valid as the peer is not necessarily able to receive the increased packet size. t set openmode active|passive By default, .Ar openmode is always .Ar active . That is, .Nm will always initiate LCP/IPCP/CCP negotiation. If you want to wait for the peer to initiate negotiations, you may use the value .Ar passive . t set parity odd|even|none|mark This allows the line parity to be set. The default value is .Ar none . t set phone telno[|telno]...[:telno[|telno]...]... This allows the specification of the phone number to be used in place of the \\\\T string in the dial and login chat scripts. Multiple phone numbers may be given separated by a pipe (|) or a colon (:). Numbers after the pipe are only dialed if the dial or login script for the previous number failed. Numbers separated by a colon are tried sequentially, irrespective of the reason the line was dropped. If multiple numbers are given, .Nm will dial them according to these rules until a connection is made, retrying the maximum number of times specified by .Dq set redial below. In .Fl background mode, each number is attempted at most once. t set reconnect timeout ntries Should the line drop unexpectedly (due to loss of CD or LQR failure), a connection will be re-established after the given .Ar timeout . The line will be re-connected at most .Ar ntries times. .Ar Ntries defaults to zero. A value of .Ar random for .Ar timeout will result in a variable pause, somewhere between 0 and 30 seconds. t set redial seconds[.nseconds] [attempts] .Nm Ppp can be instructed to attempt to redial .Ar attempts times. If more than one number is specified (see .Dq set phone above), a pause of .Ar nseconds is taken before dialing each number. A pause of .Ar seconds is taken before starting at the first number again. A value of .Ar random may be used here too. t set stopped [LCPseconds [IPCPseconds [CCPseconds]]] If this option is set, .Nm will time out after the given FSM (Finite State Machine) has been in the stopped state for the given number of .Dq seconds . This option may be useful if you see .Nm failing to respond in the stopped state, or if you wish to .Dq set openmode passive and time out if the peer doesn't send a Configure Request within the given time. Use .Dq set log +lcp +ipcp +ccp to make .Nm log all state transitions.
p The default value is zero, where .Nm doesn't time out in the stopped state. t set server|socket TcpPort|LocalName|none [password] [mask] This command tells .Nm to listen on the given socket or .Sq diagnostic port for incoming command connections. This is not possible if .Nm is in interactive mode. The word .Ar none instructs .Nm to close any existing socket. If you wish to specify a unix domain socket, .Ar LocalName must be specified as an absolute file name, otherwise it is assumed to be the name or number of a TCP port. You may specify the octal umask that should be used with unix domain sockets as a four character octal number beginning with .Sq 0 . Refer to .Xr umask 2 for umask details. Refer to .Xr services 5 for details of how to translate TCP port names.
p You may also specify the password that must be used by the client when connecting to this socket. If the password is not specified here,
a /etc/ppp/ppp.secret is searched for a machine name that's the same as your local host name without any domain suffix. Refer to .Xr hostname 1 for further details. If a password is specified as the empty string, no password is required.
p When using .Nm with a server socket, the .Xr pppctl 8 command is the preferred mechanism of communications. Currently, .Xr telnet 1 can also be used, but link encryption may be implemented in the future, so .Xr telnet 1 should not be relied upon. t set speed value This sets the speed of the serial device. t set timeout Idle [ lqr [ retry ] ] This command allows the setting of the idle timer, the LQR timer (if enabled) and the retry timer. t set ns x.x.x.x y.y.y.y This option allows the setting of the Microsoft DNS servers that will be negotiated. t set nbns x.x.x.x y.y.y.y This option allows the setting of the Microsoft NetBIOS DNS servers that will be negotiated. t set help|? This command gives a summary of available set commands. .El
p t shell|! [command] If .Dq command is not specified a shell is invoked according to the .Dv SHELL environment variable. Otherwise, the given command is executed. Any of the pseudo arguments .Dv HISADDR , .Dv INTERFACE and .Dv MYADDR will be replaced with the appropriate values. Use of the ! character requires a following space as with any other commands. You should note that this command is executed in the foreground - .Nm will not continue running until this process has exited. Use the .Dv bg command if you wish processing to happen in the background. t show var This command allows the user to examine the following: l -tag -width 20 t show [adio]filter List the current rules for the given filter. t show auth Show the current authname and encryption values. If you have built .Nm without DES support, the encryption value is not displayed as it will always be .Ar MD5 . t show ccp Show the current CCP statistics. t show compress Show the current compress statistics. t show escape Show the current escape characters. t show hdlc Show the current HDLC statistics. t show ipcp Show the current IPCP statistics. t show lcp Show the current LCP statistics. t show loopback Show the current loopback status. t show log Show the current log values. t show mem Show current memory statistics. t show modem Show current modem statistics. t show mru Show the current MRU. t show mtu Show the current MTU. t show proto Show current protocol totals. t show reconnect Show the current reconnect values. t show redial Show the current redial values. t show stopped Show the current stopped timeouts. t show route Show the current routing tables. t show timeout Show the current timeout values. t show msext Show the current Microsoft extension values. t show version Show the current version number of .Nm ppp . t show help|? Give a summary of available show commands. .El
p t term Go into terminal mode. Characters typed at the keyboard are sent to the modem. Characters read from the modem are displayed on the screen. When a .Nm peer is detected on the other side of the modem, .Nm automatically enables Packet Mode and goes back into command mode. .El
p .Sh MORE DETAILS l -bullet -compact t Read the example configuration files. They are a good source of information. t Use .Dq help , .Dq show ? , .Dq alias ? , .Dq set ? and .Dq set ? <var> commands. .El
p .Sh FILES .Nm Ppp refers to four files:
a ppp.conf ,
a ppp.linkup ,
a ppp.linkdown and
a ppp.secret . These files are placed in the
a /etc/ppp directory. l -tag -width flag t Pa /etc/ppp/ppp.conf System default configuration file. t Pa /etc/ppp/ppp.secret An authorisation file for each system. t Pa /etc/ppp/ppp.linkup A file to check when .Nm establishes a network level connection. t Pa /etc/ppp/ppp.linkdown A file to check when .Nm closes a network level connection. t Pa /var/log/ppp.log Logging and debugging information file. Note, this name is specified in
a /etc/syslogd.conf . See .Xr syslog.conf 5 for further details. t Pa /var/spool/lock/LCK..* tty port locking file. Refer to .Xr uucplock 3 for further details. t Pa /var/run/tunN.pid The process id (pid) of the .Nm program connected to the tunN device, where .Sq N is the number of the device. This file is only created in .Fl background , .Fl auto and .Fl ddial modes. t Pa /var/run/ttyXX.if The tun interface used by this port. Again, this file is only created in .Fl background , .Fl auto and .Fl ddial modes. t Pa /etc/services Get port number if port number is using service name. .El
p .Sh SEE ALSO .Xr at 1 , .Xr chat 8 , .Xr crontab 5 , .Xr ftp 1 , .Xr getty 8 , .Xr gzip 1 , .Xr hostname 1 , .Xr inetd 8 , .Xr init 8 , .Xr login 1 , .Xr passwd 5 , .Xr ping 8 , .Xr pppctl 8 , .Xr pppd 8 , .Xr route 8 , .Xr syslog 3 , .Xr syslog.conf 5 , .Xr syslogd 8 , .Xr tcpdump 1 , .Xr telnet 1 , .Xr traceroute 8 , .Xr uucplock 3 .Sh HISTORY This program was originally written by Toshiharu OHNO (tony-o@iij.ad.jp), and was submitted to FreeBSD-2.0.5 by Atsushi Murai (amurai@spec.co.jp). It has since had an enormous face lift and looks substantially different.
p The zlib compression algorithms used in the DEFLATE protocol are provided thanks to Jean-loup Gailly (Copyright 1995).