mirroring cable model traffic

[Chas Meyer <chas.meyer () gmail com>]

Just a quick question - I've decided to run snort on all the traffic  
running in and out of my house.  Since my home switch is unmanaged (I  
can't set up a mirror port), I've done it ghetto style.  I set up a  
hub in between my cable modem and my router/switch and plugged the  
interface on my server that I would like to use for sniffing into that  
hub.  However, when I test this rig with tcpdump (using command: sudo  
tcpdump -vvv -i eth0), all I am getting is arp requests on my ISP's  
network, even with internet use from my local network.  Shouldn't I  
also be seeing all the traffic that is originating and terminating at  
my router/switch?  Any help would be great.  Thanks.