DNS technology seems simple but is actually very complicated with hundreds of RFC documentations. So far there are still no recognized technical solutions to address some of the problems, for example, how to realize equivalent resolution and even equivalent application at a number of similar domain names and their subdomain names.

Tree Structure of DNS:

DNS, the abbreviation of Domain Name System, utilizes layered distributed database to process the mapping between domain names and IP addresses. Applied to TCP/IP network such as Internet, DNS looks up computers and services by means of user-friendly names. When user enters DNS name in applications, DNS service can resolve the name into other information related to it, for example, IP address.