NetReg
automated system that requires an unknown DHCP client to register their hardware before gaining full network access. Through a simple web interface, the client is prompted for their user identification. Powerful scripts then retrieve the client's network fingerprint and store it along with the user's information in a database. The database provides administrators with real-time information for troubleshooting and auditing their networks.
Spanning Multiple Subnets
A DHCP server can provide IP addresses to clients spanning multiple subnets if the router that separates them can act as an RFC 1542(BOOTP) relay agent.