Domain
Name Service (D.N.S)
The DNS (Domain Name Service) is a
standard technology for managing the names of Websites and other Internet
domains. DNS technology allows you to type names into your Web browser like (solutions-ever.blogspot.com)
and your computer to automatically resolve that address on the Internet. A key
element of the DNS is a worldwide collection of DNS servers.
DNS server is any computer registered to join the Domain Name System.
A DNS server runs special purpose networking features public IP addresses
and contains a database of network names and addresses for other Internet
hosts.
DNS
Root Server
DNS servers communicate with each
other using private network protocols. All DNS servers are organized in a
hierarchy. At the top level of the hierarchy, so-called root servers store the complete database of Internet domain
names and their corresponding IP addresses.
DNS
Hierarchy
The DNS is a distributed system,
meaning that only the 13 root servers contain the complete database of domain
names and IP addresses. All other DNS servers are installed at lower levels of
the hierarchy and maintain only certain pieces of the overall database.
Lower level DNS servers are owned by
businesses or ISP’s. For example, yahoo maintains various DNS servers around
the world that manage the yahoo.com, and other domains. Your ISP also maintains
DNS servers as part of your Internet connection setup.
DNS networking is based on the Client/Server
architecture. Your Web browser functions as a DNS client and issues requests to
your Internet provider's DNS servers when navigating between Web sites.
When a DNS server receives a request
not in its database, it temporarily transforms from a server to a DNS client.
The server automatically passes that request to another DNS server or up to the
next higher level in the DNS hierarchy as needed. Eventually the request
arrives at a server that has the matching name and IP address in its database and
the response flows back through the chain of DNS servers to your client.
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