NAME pppd - Point to Point Protocol packet driver SYNOPSIS pppd [ COMn ] [ speed ] [ options ] DESCRIPTION The Point-to-Point Protocol (PPP) provides a method for transmitting datagrams over serial point-to-point links. PPP is composed of three parts: a method for encapsulating datagrams over serial links, an extensible Link Control Protocol (LCP), and a family of Network Control Protocols (NCP) for establishing and configuring different network- layer protocols. The DOS pppd provides the encapsulation scheme, basic LCP, authentication support, and an NCP for establishing and configuring the Internet Protocol (IP) (called the IP Control Protocol, IPCP). FREQUENTLY USED OPTIONS Specifies the COM port to use for communicating with the peer. Port COM1 through COM4 can be used, the standar base address/irq is assumed unless you change the default with another options. Basic testing (through BIOS) is done for ensure COM avai- lability. base Specifies the base address for the COM port, in case it is a non-standar one. The number can be entered in hex, octal or decimal, following the C language rules for parsing numbers (0xnnn is hex for example). No attempt is done for verifying that a valid COM port exists at the address, so use with care. irq Specifies the irq number used by the COM port. The same considerations as above applies. pktvec Specifies the vector number to be hooked by the packet driver interface. The valid range is from 0x60-0x66, 0x68-0x6F and 0x78-0x7E. If this option is not used, the driver searches for the first free vector in this range (usually 0x60). namsrv Set IP addresses to return in the DNS field of BOOTP replies, supported only by the ethernet emulation versions EPPPD.EXE and EPPPDD.EXE. Up to two name- servers can be specified. This option is useful for configuring DOS Internet applications through BOOTP. Specifies the speed for serial comunications. Up to 115200 baud can be programmed, beware that serial ports that have the old 8250 UART can not handle speeds higher than 9600 in a reliable way. The number can be entered in hex, octal or decimal, as in the above options. asyncmap Set the async character map to . This map describes which control characters cannot be suc- cessfully received over the serial line. pppd will ask the peer to send these characters as a 2-byte escape sequence. The argument is a 32 bit hex num- ber with each bit representing a character to escape. Bit 0 (00000001) represents the character 0x00; bit 31 (80000000) represents the character 0x1f or ^ . If multiple asyncmap options are given, the values are ORed together. If no asyncmap option is given, no async character map will be negotiated for the receive direction; the peer should then escape all control characters. connect

Use the command specified by

to set up the serial line. The CHAT.EXE program must be used with this option, as the COM port is controled by pppd and a private interface is used between the two programs for granting COM access to CHAT. pppd will look in the current directory first, then in the same directory where pppd resides. crtscts Use hardware flow control (i.e. RTS/CTS) to control the flow of data on the serial port. If neither the crtscts nor the -crtscts option is given, the hardware flow control setting for the serial port is left unchanged. escape xx,yy,... Specifies that certain characters should be escaped on transmission (regardless of whether the peer requests them to be escaped with its async control character map). The characters to be escaped are specified as a list of hex numbers separated by commas. Note that almost any character can be specified for the escape option, unlike the asyncmap option which only allows control charac- ters to be specified. The characters which may not be escaped are those with hex values 0x20 - 0x3f or 0x5e. file Read options from file (the format is described below). mru Set the MRU [Maximum Receive Unit] value to for negotiation. pppd will ask the peer to send pack- ets of no more than bytes. The minimum MRU value is 128. The default MRU value is 1500. A value of 296 is recommended for slow links (40 bytes for TCP/IP header + 256 bytes of data). mtu Set the MTU [Maximum Transmit Unit] value to . Unless the peer requests a smaller value via MRU negotiation, pppd will request that the kernel net- working code send data packets of no more than n bytes through the PPP network interface. netmask Set the interface netmask to , a 32 bit netmask in "decimal dot" notation (e.g. 255.255.255.0). If this option is given, the value specified is ORed with the default netmask. The default netmask is chosen based on the negotiated remote IP address; it is the appropriate network mask for the class of the local IP address and that satisfies the following condition: ( & ) = ( & ) The default netmask is right shifted if necessary until the above condition is reached. OPTIONS : Set the local and/or remote interface IP addresses. Either one may be omitted. The IP addresses must be given in decimal dot notation (e.g. 150.234.56.78). IP addresses will be obtained from the peer if not specified in any option. Thus, in simple cases, this option is not required. If a local and/or remote IP address is specified with this option, pppd will not accept a different value from the peer in the IPCP negotiation, unless the ipcp- accept-local and/or ipcp-accept-remote options are given, respectively. -ac Disable Address/Control compression negotiation (use default, i.e. address/control field compres- sion disabled). -all Don't request or allow negotiation of any options for LCP and IPCP (use default values). -am Disable asyncmap negotiation (use the default asyncmap, i.e. escape all control characters). -as Same as asyncmap -crtscts Disable hardware flow control (i.e. RTS/CTS) on the serial port. If neither the crtscts nor the -crtscts option is given, the hardware flow control setting for the serial port is left unchanged. -d Increase debugging level (same as the debug option). debug Increase debugging level (same as -d). If this option is given, pppd will log the contents of all control packets sent or received in a readable form. The packets are logged through DOS standar output, which can be redirected to a file. Some debug output is sent to DOS standar error. hostname Sets local host name for authentication purposes. domain Append the domain name to the local host name for authentication purposes. -ip Disable IP address negotiation. If this option is used, the remote IP address must be specified with an option on the command line or in an options file. ipcp-accept-local With this option, pppd will accept the peer's idea of our local IP address, even if the local IP address was specified in an option. ipcp-accept-remote With this option, pppd will accept the peer's idea of its (remote) IP address, even if the remote IP address was specified in an option. ipcp-max-configure Set the maximum number of IPCP configure-request transmissions to (default 10). ipcp-max-failure Set the maximum number of IPCP configure-NAKs returned before starting to send configure-Rejects instead to (default 10). ipcp-max-terminate Set the maximum number of IPCP terminate-request transmissions to (default 3). ipcp-restart Set the IPCP restart interval (retransmission time- out) to seconds (default 3). kdebug n Enable debugging code in the low-level PPP driver. The argument n is a number which is the sum of the following values: 1 to enable general debug messages, 2 to request that the contents of received packets be printed, and 4 to request that the contents of transmitted packets be printed. lcp-echo-failure If this option is given, pppd will presume the peer to be dead if n LCP echo-requests are sent without receiving a valid LCP echo-reply. If this happens, pppd will terminate the connection. Use of this option requires a non-zero value for the lcp-echo- interval parameter. This option can be used to enable pppd to terminate after the physical connec- tion has been broken (e.g., the modem has hung up) in situations where no hardware modem control lines are available. lcp-echo-interval If this option is given, pppd will send an LCP echo-request frame to the peer every n seconds. Under Linux, the echo-request is sent when no pack- ets have been received from the peer for n seconds. Normally the peer should respond to the echo- request by sending an echo-reply. This option can be used with the lcp-echo-failure option to detect that the peer is no longer connected. lcp-max-configure Set the maximum number of LCP configure-request transmissions to (default 10). lcp-max-failure Set the maximum number of LCP configure-NAKs returned before starting to send configure-Rejects instead to (default 10). lcp-max-terminate Set the maximum number of LCP terminate-request transmissions to (default 3). lcp-restart Set the LCP restart interval (retransmission time- out) to seconds (default 3). local Don't use the modem control lines. With this option, pppd will ignore the state of the CD (Car- rier Detect) signal from the modem and will not change the state of the DTR (Data Terminal Ready) signal. modem Use the modem control lines. This option is the default. With this option, pppd will wait for the CD (Carrier Detect) signal from the modem to be asserted when opening the serial device (unless a connect script is specified), and it will drop the DTR (Data Terminal Ready) signal briefly when the connection is terminated and before executing the connect script. -mn Disable magic number negotiation. With this option, pppd cannot detect a looped-back line. -mru Disable MRU [Maximum Receive Unit] negotiation. With this option, pppd will use the default MRU value of 1500 bytes. -p Same as the passive option. -pap Don't agree to authenticate using PAP. pap-max-authreq Set the maximum number of PAP authenticate-request transmissions to (default 10). pap-restart Set the PAP restart interval (retransmission time- out) to seconds (default 3). pap-timeout Set the maximum time that pppd will wait for the peer to authenticate itself with PAP to seconds (0 means no limit). -pc Disable protocol field compression negotiation (use default, i.e. protocol field compression dis- abled). remotename Set the assumed name of the remote system for authentication purposes to . +ua

Agree to authenticate using PAP [Password Authenti- cation Protocol] if requested by the peer, and use the data in file

for the user and password to send to the peer. The file contains the remote user name, followed by a newline, followed by the remote password, followed by a newline. This option is obsolescent. user Set the user name to use for authenticating this machine with the peer using PAP to . passwd

Set user password to use for authenticating this machine with the peer using PAP to

. xonxoff Use software flow control (i.e. XON/XOFF) to con- trol the flow of data on the serial port. OPTIONS FILES Options can be taken from files as well as the command line. pppd reads options from the files .\pppd.cfg (also in the directory where the pppd program is located) and and .\pppdrc.cfg before looking at the command line. After parsing command line options, a file named .\pppdcom?.cfg is tried, the ? will be replaced with the current COM number. An options file is parsed into a series of words delimited by whitespace. Whitespace can be included in a word by enclosing the word in quotes ("). A backslash (\) quotes the following character. A hash (#) starts a comment, which continues until the end of the line. If you need to put DOS path separators in options files, you must use the escape sequence \\, for example: +ua c:\\secrets\\paplogin This is needed because the \ character is interpreted as an escape control code begining. AUTHENTICATION Only PAP authentication with the peer is supported by this release. It doesn't support CHAP nor authenticating the peer to ourselves, so it is not well suited for acting as a PPP server. You are required to supply two items for authentication, an user name and a password. Options are available for setting these two items. An authentication file can also be used with the +ua filename option. EXAMPLES In the simplest case, you can connect the serial ports of two machines and issue a command like pppd com1 9600 passive If the other machine is running UNIX and has a getty process attached to the serial port we want to use, the process of logging in to the other machine and start- ing pppd can be automated by using the connect option to run chat, for example: pppd com1 38400 connect "chat '' '' 'login:' 'username' 'Password:' 'password' '% ' 'exec pppd passive'" (Note however that running chat like this will leave the password visible in the parameter list of pppd and chat.) If your serial connection is any more complicated than a piece of wire, you may need to arrange for some control characters to be escaped. In particular, it is often use- ful to escape XON (^Q) and XOFF (^S), using asyncmap a0000. If the path includes a telnet, you probably should escape ^] as well (asyncmap 200a0000). If the path includes an rlogin, you will need to use the escape ff option on the end which is running the rlogin client, since many rlogin implementations are not transparent; they will remove the sequence [0xff, 0xff, 0x73, 0x73, followed by any 8 bytes] from the stream. DIAGNOSTICS The debug versions PPPDD.EXE and EPPPDD.EXE incorporates additional code for diagnostic purposes. The loggin will be sent to DOS standar output and error/informative messages will go to DOS standar error. Logging will cease after the driver going resident, so its usefulness is limited to debug link establishment phase. The debug option causes the contents of all control pack- ets sent or received to be logged, that is, all LCP, PAP, CHAP or IPCP packets. This can be useful if the PPP nego- tiation does not succeed. If debugging is enabled at com- pile time, the debug option also causes other debugging messages to be logged. FILES .\ip-up.bat A DOS batch file generated by pppd that will set environment variables with the current PPP link parameters, such local IP, remote IP, etc. This file can be called from inside another batch file and then use the environment variables for DOS Internet applications configuration. full_path_to_pppd\pppd.cfg .\pppd.cfg System default options for pppd, read before user default options or command-line options. .\pppdrc.cfg User default options, read before command-line options. .\pppdcom?.cfg System default options for the serial port being used, read after command-line options. SEE ALSO RFC1144 Jacobson, V. Compressing TCP/IP headers for low- speed serial links. 1990 February. RFC1321 Rivest, R. The MD5 Message-Digest Algorithm. 1992 April. RFC1332 McGregor, G. PPP Internet Protocol Control Proto- col (IPCP). 1992 May. RFC1334 Lloyd, B.; Simpson, W.A. PPP authentication proto- cols. 1992 October. RFC1548 Simpson, W.A. The Point-to-Point Protocol (PPP). 1993 December. RFC1549 Simpson, W.A. PPP in HDLC Framing. 1993 December NOTES You can use CTRL+C for aborting the driver operations before it goes resident. For closing the PPP link and driver deinstallation you must use a standar packet driver terminator, like TERMIN.COM from Russell Nelson (CRYNWR). AUTHORS Drew Perkins, Brad Clements, Karl Fox, Greg Christy, Brad Parker, Paul Mackerras (paulus@cs.anu.edu.au).