PPPOE-SNIFF

Section: Maintenance Commands (8)
Updated: 3 July 2000
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NAME

pppoe-sniff - examine network for non-standard PPPoE frames

SYNOPSIS

pppoe-sniff [options]

DESCRIPTION

pppoe-sniff listens for likely-looking PPPoE PADR and session frames and deduces extra options required for pppoe(8) to work.

Some DSL providers seem to use non-standard frame types for PPPoE frames, and/or require a certain value in the Service-Name field. It is often easier to sniff those values from a machine which can successfully connect rather than try to pry them out of the DSL provider.

To use pppoe-sniff, you need two computers, a DSL modem and an Ethernet hub (not an Ethernet switch.)

If the DSL modem normally connects directly to your computer's Ethernet card, connect it to the "uplink" port on the Ethernet hub. Plug two computers into normal ports on the hub. On one computer, run whatever software the DSL provider gave you on whatever operating system the DSL provider supports. On the other computer, run Linux and log in as root.

On the Linux machine, put the Ethernet interface into promiscuous mode and start pppoe-sniff. If the ethernet interface is eth0, for example, type these commands:

        ifconfig eth0 promisc
        pppoe-sniff -I eth0

On the other machine, start your DSL connection as usual. After a short time, pppoe-sniff should print recommendations for the value of PPPOE_EXTRA. Set this value in /etc/ppp/pppoe.conf.

After pppoe-sniff finishes (or you stop it if it seems hung), remember to turn off promiscuous mode:

        ifconfig eth0 -promisc

OPTIONS

-I interface: The -I option specifies the Ethernet interface to use. Under Linux, it is typically eth0 or eth1. The interface should be "up" and in promiscuous mode before you start pppoe-sniff.
-V: The -V option causes pppoe-sniff to print its version number and exit.

BUGS

pppoe-sniff only works on Linux.

AUTHORS

pppoe-sniff was written by Dianne Skoll <dianne@skoll.ca>.

The pppoe home page is https://dianne.skoll.ca/projects/rp-pppoe/.