Cacti + port mirror

[myspamhurts]

Hey all. I've read countless entries on that this is a good idea. But I haven't seen anywhere where someone tells how you actually do it.

I have Cacti on Ubuntu Desktop 12.04. 2 NICs. I know which one is eth0 and eth1. How in the world do I tell Cacti to monitor one of the NICs?

Eth0 will be used for primary machine network traffic/hosting the cacti site
Eth1 is connected to the mirrored port that I want to monitor

I understand that I will need NetTop but unsure of when/where to install it. Should I just use Cacti EZ that has all that integrated? I'm trying not too since it hasn't been updated in several years.

Any directions on this would be great! Thanks all!