A proposal for a NAT traversal system that does not require additional functions at terminals

Demand for users accessing networks anytime and from anywhere has been increasing in the forthcoming advent of ubiquitous society. Users would strongly desire to acquire the capability of accessing to their own terminals of the home or company networks from the outside. However, networks are usually constructed with private IP addresses, and a NAT stands on the way of a communication path. In such an environment, communication cannot be initiated from terminals in the Internet. This is called "NAT traversal problem". To solve this problem, we propose a new NAT traversal system based on the modified DNS server and NAT router and concerted work between them.