Those computers on the campus network with invalid network connection registration information on MAC/IP addresses, users' names, user locations, etc or with no registration at all are like illegal residents in the University cyber-community. Some are using unauthorized or other users' IP addresses to conduct their network activities while others become anonymous network users as no one officially knows their true identities or whereabouts, hence they may potentially pose serious security threats to our cyber-community especially during a crisis situation. Take the Windows client PCs as an example, when they become targets during an outbreak of viruses or at the imminent attacks by the hackers, the Computing Services Centre (CSC) could not reach them to issue timely alert or lend them a helping hand. When they become victims, the CSC would not be able to locate them quickly enough to stop them from further spreading the virus or from being exploited by hackers to launch other attacks.

As a matter of fact, during the investigations of the recent outbreak of virus and hacking activities, the CSC discovered that the information recorded in its network database (which contains such information as: IP addresses, MAC addresses, and the locations and names of their owners, etc) for some reasons have quite a number of discrepancies. This not only leads to delay in rectifying problems and notifying the victim users but also causes unnecessary inconvenience or disturbance to those who were thought to be involved but in fact have nothing to do with those incidents.

Moreover, as almost all networking management tools such as firewalls, intrusion detection tools, etc, can recognize only IP addresses or MAC addresses (instead of users' names or computer node names), therefore the accuracy of these addresses are also vital for deploying these tools in order to provide users' machines the necessary protection and timely alerts or warnings.