Hi everyone,
At work we operate a secured wifi. We give the connection password to staff so that they can connect with their laptops, PDA's etc. But I suspect that this password is being given out to non-staff also.

I know I could just change the password and re-issue the new one - but I would really like to get an understanding of how and when people are connecting - for how long and how much data are they downloading.

Is there any software I can install to monitor this sort of activity?
We run all MS Server machines, with one Linux VM running Zenoss Core.

Thanks,
Bryan