ppdpo

pppd [ options ] [ tty_name ] [ speed ]

call name
    Execute the named /etc/ppp/options.name file.

connect command
    Specify a command to be executed to connect to the peer.

disconnect command
    Specify a command to be executed to disconnect from the peer.

file filename
    Execute the specified filename as a configuration file.

lock
    Create a lock file to prevent multiple invocations.

modem
    Use modem control lines.

silent
    Suppress all normal log output.

debug
    Increase debugging level.

plugin filename
    Load the specified plugin from filename.

The `pppd` command is used to establish a Point-to-Point Protocol over Ethernet (PPPoE) connection, commonly used for DSL internet connections. It acts as a client that negotiates the connection parameters (like authentication and IP addressing) with the PPPoE server provided by the Internet Service Provider (ISP). Configuration files, typically located in `/etc/ppp/`, define the connection settings, including user names, passwords, and interface information. `pppd` handles the authentication process using protocols like PAP or CHAP. Upon successful authentication, `pppd` configures the network interface, assigns an IP address, and establishes the necessary routing rules to enable internet access. The `pppoe` command is often used in conjunction with `pppd` to discover PPPoE servers before `pppd` establishes the connection. `pppd` is a core utility for many DSL setups and requires careful configuration for proper operation. It's a versatile tool with many options allowing customization for different ISP requirements and network configurations. The `pppd` daemon can be started and stopped via the command line, or managed by system services.

Incorrect configuration of `pppd` can lead to failed connections or security vulnerabilities. Configuration files must be secured to prevent unauthorized access to authentication credentials.

Key configuration files are located in `/etc/ppp/`. These include `options` (global options), `peers/*` (peer-specific options), and `chap-secrets` and `pap-secrets` (authentication credentials).
Always protect sensitive information.

Common issues include incorrect user names/passwords, misconfigured interfaces, and firewall restrictions. Checking system logs (e.g., `/var/log/syslog`) is crucial for diagnosing connection problems.
Use debug option for verbose logging.

The `pppd` utility has been a staple of Unix-like systems for establishing PPP connections since the rise of dial-up networking. It has evolved over time to support various authentication and compression protocols. With the advent of DSL and other broadband technologies, `pppd` was adapted to support PPPoE, becoming essential for connecting to many ISPs. Ongoing development and maintenance have ensured its continued relevance and compatibility with modern network environments. The demand for secure and reliable internet connectivity over PPPoE connections has driven the continual refinement and debugging of `pppd` through the years.

pppoe(8), chat(8), ifconfig(8), route(8)