program to monitor router logs

I have a home office with 4 computers connected to a Netgear FVS 318v3 firewall/router.

Today I learned that my ISP has a monthly bandwidth cap (Comcast, 250 GB). While I dont think there is any way I would ever hit that, I would like a way to monitor not only bandwidth usage but also any suspicious activity on the WAN side of the firewall/router.

Not long ago I used a share ware program called Link Logger to watch an external HW firewall… this does not appear to be available for linux

Any one have any suggestions on an app to read the FVS logs and bandwidth usage??