Chapter 36

Solaris PPP 4.0 Reference

This chapter provides detailed conceptual information about Solaris PPP 4.0. Topics include the following:

• "Using PPP Options in Files and on the Command Line"

• "Configuring User-Specific Options"

• "Specifying Information for Communicating With the Dial-in Server"

• "Configuring Modems for a Dial-up Link"

• "Defining the Conversation on the Dial-up Link"

• "Authenticating Callers on a Link"

• "Creating an IP Addressing Scheme for Callers"

• "Creating PPPoE Tunnels for DSL Support"

Using PPP Options in Files and on the Command Line

Solaris PPP 4.0 contains a large set of options, which you use to define your PPP configuration. You use these options in the PPP configuration files, or on the command line, or by using a combination of files and command-line options. This section contains detailed information about the use of PPP options in configuration files and as arguments to PPP commands.

Where to Define PPP Options

Solaris PPP 4.0 is very flexible in the manner in which you can configure it. You can define PPP options in the following places:

• PPP configuration files

• PPP commands that are issued on the command line

• A combination of both places

The next table lists the PPP configuration files and commands.

Table 36-1 Summary of PPP Configuration Files and Commands

File or Command	Definition	For Information
/etc/ppp/options	File that contains characteristics that apply by default to all PPP links on the system, for example, whether the machine requires peers to authenticate themselves. If this file is absent, non-root users are prohibited from using PPP.	"/etc/ppp/options Configuration File"
/etc/ppp/options.ttyname	File that describes the characteristics of all communications over the serial port ttyname.	"/etc/ppp/options.ttynameConfiguration File"
/etc/ppp/peers	Directory that usually contains information about peers with which a dial-out machine connects. Files in this directory are used with the call option of the pppd command.	"Specifying Information for Communicating With the Dial-in Server"
/etc/ppp/peers/peer-name	File that contains characteristics of the remote peer peer-name, such as its phone number and chat script for negotiating the link with the peer.	"/etc/ppp/peers/peer-nameFile"
/etc/ppp/pap-secrets	File that contains the necessary security credentials for Password Authentication Protocol (PAP) authentication.	"/etc/ppp/pap-secrets File"
/etc/ppp/chap-secrets	File that contains the necessary security credentials for Challenge-Handshake Authentication Protocol (CHAP) authentication.	"/etc/ppp/chap-secrets File"
~/.ppprc	File in the home directory of a PPP user, most often used with dial-in servers. This file contains specific information about each user's configuration.	"Configuring User-Specific Options"
pppd options	Command and options for initiating a PPP link and describing its characteristics.	"How PPP Options Are Processed"

Refer to the pppd(1M) man page for details on the PPP files and comprehensive descriptions of all options available to the pppd command. Sample templates for all the PPP configuration files are available in /etc/ppp.

How PPP Options Are Processed

All Solaris PPP 4.0 operations are handled by the pppd daemon, which starts when a user runs the pppd command. When a user calls a remote peer, the following occurs:

1. The pppd daemon parses the following:

   • /etc/ppp/options

   • $HOME/.ppprc

   • Any files that are opened by the file or call option in /etc/ppp/options and $HOME/.ppprc

2. pppd scans the command line to determine the device in use. The daemon does not yet interpret any options that are encountered.

3. pppd tries to discover the serial device to use by using the following criteria:

   1. If a serial device is specified on the command line, or a previously processed configuration file, pppd uses the name of that device.

   2. If no serial device is named, then pppd searches for the notty, pty, or socket option on the command line. If one of these options is specified, pppd assumes that no device name exists.

   3. Otherwise, if pppd discovers that standard input is attached to a tty, then the name of the tty is used.

   4. If pppd still cannot find a serial device, it terminates the connection and issues an error.

4. pppd then checks for the existence of the /etc/ppp/options.ttyname file. If the file is found, pppd parses the file.

5. pppd processes any options on the command line.

6. pppd negotiates the Link Control Protocol (LCP) to set up the link.

7. (Optional) If authentication is required, pppd reads /etc/ppp/pap-secrets or /etc/ppp/chap-secrets to authenticate the opposite peer.

The file /etc/ppp/peers/peer-name is read when the pppd daemon encounters the option call peer-name on the command line or in the other configuration files.