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resource box below is included. ---------------------------------------------------------- What is DNS?By Stephen Bucaro
Have you ever wondered what happens when you enter, or click on, a web address in your browser? How does your computer connect to
Web site you requested? Part of what makes that happen is
Internet's Domain Name Service (DNS).
Similar to how every telephone has a unique number, every Web site, or "domain" on
Internet has a unique Internet Protocol (IP) address. IP addresses are 32 bit numbers represented by four bytes separated by dots. Each byte can represent a number from 0 to 255, therefore
highest IP address 255.255.255.255.
People have difficulty remembering 12 digit numbers, so web sites are are identified by names like www.sitename.com instead of their IP address. DNS is a database of domain names and their corresponding IP addresses.
In
beginning, every computer on
Internet had a list of all
domain names and their corresponding IP addresses. But that quickly became unwieldy. Now
domain name database and domain name to IP address translation is performed by computers assigned as DNS servers.
Each DNS server has data only about
domains it is serving. When a computer makes a request to its DNS, it is possible that
DNS server doesn't have
data required to answer
request. Special "root name" servers hold a list of DNS servers for top-level domains, like .com, .org, .edu etc. For example,
top-level DNS for .com lists
DNS servers for domain names ending in ".com".