Issue
What is Domain Name Service (DNS)?
Product Line
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Environment
TCP/IP Networks
Cause
DNS is a distributed hierarchical system for resolving host names into IP address. Under DNS, there is no central database with all of the Internet host information. The information is distributed among thousands of name servers organized into a hierarchy similar to the UNIX file system. DNS has a root domain at the top of the domain hierarchy that is served by a group of name servers called the root servers.
Source: TCP/IP Network Administration by Craig Hunt, O’Reilly & Associates, Inc.
Resolution
Short for Domain Name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, they're easier to remember. The Internet however, is really based on IP addresses. Every time you use a domain name, therefore, a DNS service must translate the name into the corresponding IP address. For example, the domain name www.example.com might translate to 198.105.232.4.
The DNS system is, in fact, its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one, and so on, until the correct IP address is returned.
