We have researched a regional personal computer (PC) communication network system to provide group communication services to people living in regional com- munities cost-effectively. Any protocol including IP can be used in the system, because bridging services or LAN environments are provided to users. A new dynamic DNS that interconnects a DNS server and a DHCP server is proposed. A DNS server is connected with a DHCP server by using PC MAC addresses, which are managed in a group management server. It achieves automatic address registration and provides a reliable link between DHCP and DNS. We implemented the dynamic DNS on computers and evaluated its operation (Egevang, 2004, 1631).
DNS and Dynamic Updates
The DHCP server assigns one of the reserved IP addresses to the PC that sent an address requirement to the server. It also notifies the DNS server of the relationship between the assigned IP address and the MAC address of the PC. The DNS server identifies the users PC by the MAC address and modifies and synchronizes the relationship between the hostname and IP address. Tight security is guaranteed by identifying the PC by its MAC address. A scheme using the KEY algorithm to prevent illegal alteration of DNS records is described in RFC2065. Our dynamic DNS maintains the reliability of dynamic modification of the DNS records by specifying the PC using MAC address.
Security is even tighter when the hostname is linked to a physical address than when only the hostname and IP address, which can be easily changed by users, are used. As mentioned in the previous section, the LECard automatically detects subordinate PC MAC addresses and reports them to the GMS. Therefore, the MAC addresses of all PCs are managed in the GMS. The dynamic DNS uses these addresses to achieve interworking between the DNS and DHCP servers. The configuration and operation sequence of the dynamic DNS server connected with the DHCP server and the GMS are discussed below (Vixie, 2007, 2136).
Cooperation between DNS and DHCP servers
The basic concept of the address table configuration in the dynamic DNS is shown in Fig. 6. The DNS and DHCP servers manage the IP addresses, MAC addresses, and hostnames. The relationship between the MAC address and the hostname is set in the DNS server. The relationship between the MAC address and the IP address is updated in the DHCP server. When the DHCP server receives an address assignment request from a PC, it replies with one of the pooled addresses and notifies the DNS server of the pair of newly assigned IP and MAC addresses. The DNS server then synchronizes the hostname and IP address table according to the notification. After table modification, the DNS server can return the newest IP address in response to the address inquiry from the PC.
Cooperation with GMS
Because the MAC addresses of user PCs are registered in the GMS, automatic hostname assignment becomes possible by managing the relationship between the host- name and MAC ...