[plug] Monitoring IP

[Bernard Blackham]

On Thu, 4 Jan 2001, Earnshaw, Mike wrote:
> I am looking for a program that will allow me to monitor the IP traffic
> on a router in our network. The router is not connected directly to any
> machine but a port on the network itself. I don't want to have to pay
> heaps for the software upgrade on the router to do this (according to
> the salesman :). Something like tcpdump or MRTG I suppose. As far as I
> see the crux is that the router is not piped through another machine.

Having no experience working with routers myself, my suggestion is purely
theoretical. If your network isn't switched, but rather just running on a
hub, then could a linux machine have it's network card placed in
promiscuous and watch all traffic on the network, then filter stuff going
to and from the router?

This wouldn't work if you were using a switch obviously, but having never
done this myself I can't say if it would even work on a dumb hub.

More spurious thoughts,

Bernard.

-- 
 Bernard Blackham
 bernard at blackham.com.au