Appendix A. PPP Tools

This appendix is a reference for dip, pppd, and chat. These tools are used to create dial-up IP connections for the Point-to-Point Protocol (PPP). dip and chat are both scripting languages. Creating a script that initializes the modem, dials the remote server, logs in, and configures the remote server is the biggest task in configuring a PPP connection. Chapter 6 provides examples and tutorial information about all three of the programs covered here. This appendix provides a reference to the programs.

Dial-Up IP

dip is a scripting tool designed specifically for creating SLIP and PPP connections.[154]

The syntax of the dip command is:

dip [options] [scriptfile]

The dip command is invoked with an option set, a script file specified, or both. When scriptfile is specified, dip executes the commands contained in the script file to create a point-to-point connection. Examples of scripts and dip are shown in Chapter 6. The options valid with script files are:


Runs dip in verbose mode. In this mode, dip echoes each line of the script file as it is executed and displays enhanced status messages.

-m mtu

Sets the maximum transmission unit (MTU) to the number of bytes specified by mtu. The default MTU is 296 bytes.

-p proto

Selects the serial line protocol. Possible values for proto are: SLIP, CSLIP, PPP, or TERM.

The other dip command-line options are:


Kills the last dip process you started. You can only kill a process you own, unless of course you’re root.

-l device

Specifies ...

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