.\" $Id: pppoe-sniff.8,v 1.4 2005/08/09 02:29:58 dfs Exp $ .\" LIC: GPL.TH PPPOE-SNIFF 8 "3 July 2000".\"".UC 4.SH NAMEpppoe-sniff \- examine network for non-standard PPPoE frames.SH SYNOPSIS.B pppoe-sniff \fR[\fIoptions\fR].SH DESCRIPTION\fBpppoe-sniff\fR listens for likely-looking PPPoE PADR and session framesand deduces extra options required for \fBpppoe(8)\fR 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 ofteneasier to sniff those values from a machine which can successfully connectrather than try to pry them out of the DSL provider.To use \fBpppoe-sniff\fR, you need two computers, a DSL modem andan Ethernet hub (\fInot\fR an Ethernet switch.)If the DSL modem normally connects directly to your computer'sEthernet card, connect it to the "uplink" port on the Ethernet hub.Plug two computers into normal ports on the hub.  On one computer, runwhatever software the DSL provider gave you on whatever operatingsystem the DSL provider supports.  On the other computer, run Linux andlog in as root.On the Linux machine, put the Ethernet interface into promiscuous modeand start \fBpppoe-sniff\fR.  If the ethernet interface is \fIeth0\fR,for example, type these commands:.nf	ifconfig eth0 promisc	pppoe-sniff -I eth0.fiOn the other machine, start your DSL connection as usual.  After a shorttime, \fBpppoe-sniff\fR should print recommendations for the valueof \fBPPPOE_EXTRA\fR.  Set this value in \fB/etc/ppp/pppoe.conf\fR.If \fBpppoe-sniff\fR indicates that something special is required in\fBPPPOE_EXTRA\fR, please e-mail this to \fBpppoe@roaringpenguin.com\fRalong with the name of your ISP and the manufacturer and model number ofyour DSL modem.  This information will be collated and provided on thePPPoE web page for users who do not have two computers.After \fBpppoe-sniff\fR finishes (or you stop it if it seems hung),remember to turn off promiscuous mode:.nf	ifconfig eth0 -promisc.fi.SH OPTIONS.TP.B \-I \fIinterface\fRThe \fB\-I\fR option specifies the Ethernet interface to use.  Under Linux,it is typically \fIeth0\fR or \fIeth1\fR.  The interface should be "up"and in promiscuous mode before you start \fBpppoe-sniff\fR..TP.B \-VThe \fB\-V\fR option causes \fBpppoe-sniff\fR to print its version number andexit..SH BUGS\fBpppoe-sniff\fR only works on Linux..SH AUTHORS\fBpppoe-sniff\fR was written by David F. Skoll <dfs@roaringpenguin.com>.The \fBpppoe\fR home page is \fIhttp://www.roaringpenguin.com/pppoe/\fR..SH SEE ALSOpppoe-start(8), pppoe-stop(8), pppoe-connect(8), pppd(8), pppoe.conf(5),pppoe(8), pppoe-setup(8), pppoe-status(8), pppoe-server(8), pppoe-relay(8)