NAT SERVER TRAVERSAL BY MEANS OF A RELAY SERVER

摘要

A host running an HTTP server behind a Network Address Translator (NAT) connected to an IP network uses a NAT-discovery process, e.g., a STUN test to determine the presence of the NAT. The host updates information in a redirect server based on the response of a relay server. An HTTP client host initiates a DNS query which connects it to the redirect server. The HTTP client host sends a HTTP request to the redirect server, which in turn redirects the HTTP request to a port on the packet relay server. The packet relay server relays the HTTP request to the HTTP server behind the NAT, which generates an HTTP response that is relayed back to the HTTP client. Seamless communication in an IP network is made possible by using a DDNS server that is updated using a user registration database. The IP network may have hosts located behind the NATs and hosts that are directly connected to the IP network.