DNS server, DHCP server, terminal and communication system

Abstract

The object of the present invention is to provide a DNS server and terminals both of which are capable of sending and receiving communication by means of a small number of IP addresses. In the case where a firewall is not provided, when the DNS server receives an inquiry of a FQDN, it sends a broad cast frame for searching a terminal to which an IP address is assigned via all the network devices. When a terminal monitors the broad cast frame and finds the FQDN to be its own FQDN, it returns the uni-cast frame to the DNS server. When the DNS server receives the uni-cast frame, it makes a look-up table and a reverse look-up table. As a result, the terminal can receive the communication by an ordinary method. In the case where the firewall is provided, by processing an IP address conversion between the external IP address and the internal address by the use of an IP address conversion means NAT in addition to making the look-up table and the reverse look-up table, the terminal can receive communication.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a DNS (Domain Name System) server, a DHCP (Dynamic Host Configuration Protocol) server, a terminal and a communication system of an Internet capable of supporting a large number of terminals by means of a small number of IP addresses by dynamically assigning a limited number of IP addresses only to now communicating terminals. [0003] 2. Description of the Related Art [0004] Among conventional Internets, as shown in FIG. 11, is a system for connecting a DNS server 50 to a plurality of terminals (personal computer terminals) 52a, 52b, 52c, - - - , 52n through a dedicated line or LAN / MAN 51. Usually, in the DNS server 50 are stored a look-up table for storing FQDNs (fully qualified domain name-host name) as shown in FIG. 12A and a reverse look-up table as shown in FIG. 12B. When a inquiry about a FQDN is made of a DNS server from a terminal (for example, 52a) connected to the DNS server...

AI Technical Summary

Benefits of technology

This solution effectively manages IP addresses, eliminating depletion and enabling terminals to both send and receive communications efficiently, even behind a firewall, without requiring pre-assignment of IP addresses.

Problems solved by technology

In the conventional system described above, there is presented a problem that each of the terminals 52a, 52b, 52c, - - - , 52n needs to have an address, which leads to the depletion of the IP addresses managed by the DNS server 50.

In other words, the conventional system has a problem that it is designed specifically for sending communication.

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