Re: Sniffing DSL Connection

[Crispin Cowan <crispin () immunix com>]

Chuck Swiger wrote:

> Jeff_Lopes () groove net wrote:
>
> > DSL Modem ---> Hub ---> Linksys Router ---> Internal Machines
> >
> > I then put a Linux machine on the hub and ran ethereal. No traffic!
>
> Do you have a real IP address from the DSL modem, or does your Linksys 
> do PPPOE?  If it's the latter, all of the IP traffic is being 
> encapsulated within PPP-- ethereal should still see the traffic, but 
> trying to match by IP addr will fail. 

Or, your "hub" isn't really a hub. I've encountered a recent phenomena 
where network equipment vendors are selling small devices marked as 
"hubs" that are really switches. For most purposes this doesn't matter, 
and in fact is just a free upgrade. But if you're trying to use the hub 
as a network monitoring tap, you're SOL.

Test: put the hub on some other network that you *know* is carrying 
normal IP traffic and see if you see anything.

Crispin

--
Crispin Cowan, Ph.D.           http://immunix.com/~crispin/
Chief Scientist, Immunix       http://immunix.com
           http://www.immunix.com/shop/


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