First I want to say thanks for a lot of information, which this forums provide it to us. I have issue in my network, actually I am network security administrator in my network and I am using PIX and IPS in my side. I am filtering all Internet request from my Firewall but I faced last days some end user installed and used Internet from broadband USB modem. I know there is week from our technical support they did nit disable local administrator account or maybe they already installed the broadband USB modem for the end user. My question now how can I know if there is Internet connection active in my network from other source like broadband USB modem or dialup connection.
Thanks for your time to read my issue.


You could write a service application to detect additional IP addresses assigned to the local computer name.

You could detect USB devices. Every USB device has a ManufacturerId and a ProductId. Turns out most types of devices are usually made by few companies. Have the service application have an internal list of known devices and periodically access a server to get the updated list. If a USB device at powerup or detected while operational is in the list handle it in different ways.

Send quiet email to admin about computer. Won't exist in logs.
Shutdown the computer.
Warn the user that you know!

use a utility like tweak and tune and render the usb ports to read only if you have any doubt than wait for the service desk phone to ring