pppd
Point-to-Point Protocol connection daemon
TLDR
Start PPP connection
$ pppd [device] [speed]
Connect with options$ pppd call [provider]
Debug mode$ pppd debug [device] [speed]
Specify authentication$ pppd user [username] password [password]
SYNOPSIS
pppd [options] [device] [speed]
DESCRIPTION
pppd is the Point-to-Point Protocol daemon that establishes and manages PPP network connections over serial links, modems, and Ethernet. It handles link negotiation, authentication (PAP, CHAP, EAP), IP address assignment, and DNS configuration.
The daemon is typically invoked through helper scripts like pon or pppoe-connect rather than directly. Provider configuration files in /etc/ppp/peers/ define connection parameters for different ISPs or VPN endpoints. Plugins extend functionality for PPPoE, RADIUS authentication, and other protocols.
PARAMETERS
DEVICE
Serial device.SPEED
Baud rate.call PROVIDER
Use provider config.debug
Enable debugging.user NAME
Username for auth.password PASS
Password for auth.noauth
Don't require auth.
CONFIGURATION
/etc/ppp/peers/
Provider configuration files defining connection parameters for each ISP or VPN endpoint. Invoked via `pppd call <provider>`./etc/ppp/pap-secrets, /etc/ppp/chap-secrets
Authentication credential files for PAP and CHAP protocols, containing username, server, and password entries./etc/ppp/options
Global default options applied to all PPP connections. Per-device options can be placed in /etc/ppp/options.<device>./etc/ppp/ip-up, /etc/ppp/ip-down
Scripts executed when the PPP link comes up or goes down, used for routing, firewall, and DNS updates.
CAVEATS
Requires root privileges. Complex configuration.
HISTORY
pppd is the standard PPP daemon for Linux networking.