pppoe-discovery

pppoe-discovery [options]

-I ifname
    Specify the Ethernet interface to use (e.g., eth0).

-T timeout
    Set timeout for discovery in seconds. Default is 5 seconds.

-m MRU
    Set Maximum Receive Unit (MRU). Default is 1492.

-s service_name
    Specify the PPPoE service name. Useful when multiple servers are available.

-A
    Accept any access concentrator. By default, the first one offering service is used.

-C ac_name
    Specify the Access Concentrator (AC) name. Useful if a specific AC is desired.

-U
    Do not set the DNS server IP address. Useful with some broken servers.

-e session_id
    Manually specify the PPPoE session ID. Only for debugging or specific servers.

-D file
    Dump the PPPoE packet data to file. For debugging purposes.

-V
    Show the version number and exit.

-h
    Show help message and exit.

The `pppoe-discovery` command is a part of the Roaring Penguin PPPoE client suite. It is responsible for initiating the Point-to-Point Protocol over Ethernet (PPPoE) discovery stage, which is the first phase in establishing a PPPoE connection. This command sends PPPoE Active Discovery Initiation (PADI) packets to locate PPPoE access concentrators (servers). Once a PADO (Active Discovery Offer) packet is received from an access concentrator, `pppoe-discovery` analyzes the server's capabilities, such as supported authentication protocols and Maximum Receive Unit (MRU). It then selects a suitable access concentrator, using either the first offer or based on specific criteria specified through options. The command typically works in conjunction with `pppoe` to create and manage the PPPoE connection, handling the negotiation and authentication phases that follow the discovery stage. Without it, `pppoe` cannot automatically discover a PPPoE server, and a manual configuration of PPPoE server is needed.

Example 1: To initiate PPPoE discovery on interface eth0:
pppoe-discovery -I eth0

Example 2: To specify a specific service name:
pppoe-discovery -I eth0 -s my_service

Example 3: To force accepting any concentrator:
pppoe-discovery -I eth0 -A

pppoe(8), pppoe-server(8)