A network server provisioning at least one Local Area Network (LAN) comprising a client entry store, a packet driver module, a Dynamic Host Configuration Protocol (DHCP) request handler. The LAN has one or more routing realms. The client entry store stores records representing a user device connecting to the LAN provisioned by the network server as a roaming visitor of the LAN to gain temporal access to an outside network through the LAN, and records representing one or more routing realm top-level devices provided on a top level of each routing realm of the LAN. The packet driver module inspects packets arriving from and directed to the user device, and interacts with the client entry store to process the packets. The DHCP request handler examines address data in DHCP packets received from the user device and the records in the client entry store. At least one of the packet driver module and the DHCP request handler detects roaming between routing realms by the user device based on the data of the packets and the records in the client entry store, and assigns a new Internet Protocol (IP) address to the user device when roaming by the user device is detected.