DNS

[yummy1984]

A DNS server is any computer registered to join the Domain Name System. A DNS server runs special-purpose networking software, features a public IP address,and contains a database of network names and addresses for other Internet hosts.

DNS Root Servers

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. The Internet employs 13 root servers that have become somewhat famous for their special role. Maintained by various independent agencies, the servers are aptly named A, B, C and so on up to M. Ten of these servers reside in the United States, one in Japan, one in London, UK and one in Stockholm, Sweden.
DNS Server 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.
Most lower level DNS servers are owned by businesses or Internet Service Providers (ISPs). For example, Google maintains various DNS servers around the world that manage the google.com, google.co.uk, 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 (also called DNS resolver) 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 (such as a geographically far away or rarely visited Web site), 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 (all the way to the root level if necessary), and the response flows back through the chain of DNS servers to your client.

DNS Servers and Home Networking

Computers on your home network locate a DNS server through the Internet connection setup properties. Providers give their customers the public IP address(es) of primary and backup DNS servers. You can find the current IP addresses of your DNS server configuration via several methods:

on the configuration screens of a home network router


on the TCP/IP connection properties screens in Windows Control Panel (if configured via that method)


from ipconfig or similar command line utility

 

[yummy1984]

IP address lookup is the process of translating between IP addresses and Internet domain/computer names. Forward IP address lookup converts an Internet name to an address. Reverse IP address lookup converts the number to the name.
Several Internet services support both forward and reverse IP lookup for public addresses. On the Internet, these services rely on the Domain Name System (DNS) and are known as DNS lookup and reverse DNS lookup services. See the sidebar for locations of some popular DNS lookup sites.

On a school or corporate local area network (LAN), private IP address lookups are also possible. These networks use internal name servers that perform the comparable functions to DNS servers on the Internet. In addition to DNS, the Windows Internet Naming Service (WINS) is another technology that can be used to build IP lookup services on private networks.

Years ago, before the advent of dynamic IP addressing, many smaller business networks lacking name servers managed private IP lookups through hosts files. Hosts files contained simple lists of static IP addresses and associated computer names. This IP lookup mechanism is sitll used on some Unix computer networks. It can also be used on home networks without a router and with static IP addressing in place. DHCP-based networks, like most home networks today, rely on the DHCP server to maintain hosts files.

Utility programs provided with the computer's network operating system (NOS) allow IP address lookups on both private LANs and the Internet. In Windows, for example, the nslookup command supports lookups via name servers and/or hosts files.

 

[jitendra05]

A DNS server is any computer registered to join the Domain Name System. A DNS server runs special-purpose networking software, features a public IP address,and contains a database of network names and addresses for other Internet hosts.

DNS Root Servers

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. The Internet employs 13 root servers that have become somewhat famous for their special role. Maintained by various independent agencies, the servers are aptly named A, B, C and so on up to M. Ten of these servers reside in the United States, one in Japan, one in London, UK and one in Stockholm, Sweden.
DNS Server 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.
Most lower level DNS servers are owned by businesses or Internet Service Providers (ISPs). For example, Google maintains various DNS servers around the world that manage the google.com, google.co.uk, 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 (also called DNS resolver) 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 (such as a geographically far away or rarely visited Web site), 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 (all the way to the root level if necessary), and the response flows back through the chain of DNS servers to your client.

DNS Servers and Home Networking

Computers on your home network locate a DNS server through the Internet connection setup properties. Providers give their customers the public IP address(es) of primary and backup DNS servers. You can find the current IP addresses of your DNS server configuration via several methods:

on the configuration screens of a home network router


on the TCP/IP connection properties screens in Windows Control Panel (if configured via that method)


from ipconfig or similar command line utility

Hey friend, as we know that DNS is the domain name server which maintain the domain names and then convert them into internet protocol. Well, i am also uploading a document for the better explanation of DNS.