Proposal of a NAT traversal system independent of user terminals and its implementation

Demand for accessing networks at anytime and from anywhere has been increasing towards the forthcoming ubiquitous society. Users would like to access to their own terminals in homes or companies from the Internet. However, home networks and enterprise networks are usually constructed with private IP addresses, and therefore a NAT necessarily needs to stand on the communication paths. In such an environment, communication cannot be initiated from terminals in the Internet. This is called ldquoNAT traversal problemrdquo. To solve the problem, we propose a new NAT traversal system which does not need to modify terminals (it needs to modify the DNS server and the NAT router though). Also, we will explain our implementation method to realize the system.