6 Mbps the average processor consumption is more than 85% and starting at 8 Mbps the processor exhaustion reached 100% making the system unstable. We also measured the processor exhaustion with firewall enabled and firewall disabled for Windows XP without SP2. The processor exhaustion was found to be somewhat higher for lower attack bandwidth when the firewall was enabled compared to the case when it was not enabled. This is due to the fact that the firewall program was running in the background to defend the host computer from