Linux router: bandwidth of client

Question

I am trying to build a linux router (captive portal) with a local RADIUS server for authentication.

I want to log the bandwidth being used by each client on my network. I want to associate bandwidth at a given point in time with MAC address. My question is, how can I get the bandwidth of a current client on my network? I understand that I will need to use IP address to get this information and then look at my ARP table to determine the MAC.

I understand RADIUS accounting can do this, but I do not want to use that approach at the moment.

Ideally, I would use this information to write a small C daemon that will save this data to a mysql database for later analysis.

Thanks in advance!

Ethan

Answer 1

So long as the Internet connection and the client connections are different interfaces, you can catch everything at the routing level. You need two pieces: a NetFlow exporter to produce the data by watching the routing process and a NetFlow collector to collect the exported data and place it in a database.

If the collector only gives you IP addresses, you'll need get the IP address assignments by MAC address, probably from RADIUS accounting records.