Hi there,

Sounds like you need to monitor your bandwidth usage, using either the "ip route-cache flow" and/or the "ip accounting" commands enabled on your outside interface.

With "ip route-cache flow" enabled, you can log into the router and type "show ip cache flow". This command will show you what IPs inside are accessing which IPs outside, and will tell you what port numbers are being used.

The drawback behind using NetFlow is that it only shows you the current usage, not anything historical.

With "ip accounting" enabled, you see a log of everything that has gone through your router over a specific time period (until either the entries in the log reach a certain age, or until the log file reaches a certain size).

You can then run a program that logs into the router using SNMP and downloads the IP Accounting information. Such applications include "ManageEngine NetFlow Analyzer" and "NetQoS ReporterAnalyzer", though there are many others out there.

Using these tools correctly will tell you which devices on your network are using up the most bandwidth, and what ports are being used.

Hope this helps!

Graeme