DNS = Domain name System (or Service or Server), an Internet service that translates domain names into IP addresses. Because domain names are alphabetic, such as www.myPCcenter.com, they're easier to remember. The Internet however, is really based on numerals - IP addresses. Every time you use a url a DNS service must translate the name into the correct IP address. The DNS system is its own network. If one DNS server doesn't know how to translate a particular domain name, it asks another one until the correct IP address is foud.
Originally, each computer on the network retrieved a file called HOSTS.TXT from SRI which mapped a numerical address to a name. The Hosts file still exists on most modern operating systems either by default or through configuration and allows users to specify an IP Address to use for a hostname without checking the DNS. Many website developers use them during development of new pages. These files are also used for troubleshooting DNS errors. Such a system had obvious limitations, because of the obvious requirement that every time a computer's address changed, every computer that wanted to communicate with it would need an update to its Hosts file, which proved to be difficult.
The growth of networking called for a scalable system that would record a change in a host's address in one place only and allow others to interface with it. Other hosts would learn about the change dynamically, therefore becoming and growing a true global network of all hosts' names and their associated IP Addresses. The solution was the DNS.
|
|
