Monitor Router Traffic?

How can I Monitor Router Traffic? Not just one computer, but all connected to the router.

This thread has some tips about it: monitoring network trafic.

Additionally, I think the easiest way to do it as was said in there would be if you have a router that has this capability built-in or at least is extensible to allow it. What is the model and brand of the router with the traffic you want to monitor?

there's a couple ways:

1) your router has to support "port mirroring" (see attachment). you then tell it to take all the ports (in the case of my attachment, lets say port 1,2, and 3) and "mirror" all the data received on those ports to port 4 (at the bottom of the attachment).

Then, you'd have to connect a computer to port 4 and put a bandwidth sniffer on it.

2) Place a hub between the router (and optionally, a switch) and your clients:

Code:

ROUTER ----> HUB ----> (SWITCH) ----> COMPUTERS ON LAN

then, attach a computer to the hub:

Code:

ROUTER ----> HUB ----> (SWITCH) ----> COMPUTERS ON LAN
              |
              |------> COMPUTER

Now, whenever the switch send something to the router, your hub will get it, and broadcast that traffic to everything connected to it (the router and the computer). you'd place a sniffer on the computer.

THE PROBLEM WITH EXAMPLE 2 is that if the computers on the lan send information to other computers on the lan, that information would never get to the router since the switch would never send it to the router.

also, you waste a lot of ports on your router with the hub solution, and the hub solution might introduce a bottleneck into your lan.

Seems like wireshark would do this.
Wireshark · Download