Posted by : NotSerious CH Rabu, 29 Oktober 2014

Understanding the DNS (Domain Name System)

Domain Name System (DNS) is a system used to distribute the database to search the computer name (name resolution) in networks that use the TCP / IP (Transmission Control Protocol / Internet Protocol). DNS is used in applications that connect to the Internet such as a web browser or e-mail, which helps map the DNS host name of a computer to an IP address. Besides being used in the Internet, the DNS can also be implemented to private network or intranet where the DNS has advantages such as:

Easy, very easy to control because the user no longer be bothered to remember the IP address of a computer is quite the host name (computer name).

Consistently, the IP address of a computer can be changed but the host name is not changed.

Simple, user uses only one domain name to look good on the Internet or Intranet.


DNS can be equated with phonebook function. Where each computer on the Internet has a host name (computer name) and Internet Protocol (IP) address. In general, each client that will connect one computer to another computer, will use the host name. Then your computer will contact the DNS server to check the host name you requested is how its IP address. The IP address used to connect your computer to other computers.


DNS history

Before he used DNS, HOSTS files using the computer network containing information from the computer name and its IP address. On the Internet, this file is managed centrally and in each loaksi must copy the latest version of the HOSTS files, from here you can imagine how difficult it if there is the addition of one computer in the network, then we need to copy the latest version of this file to any location. With the increasing spread of the Internet, it is more troublesome, finally created a solution that replaces the function of the design of the DNS in the HOSTS files, with the advantages of unlimited database size, and good performace. DNS is an application services on the Internet that translates a domain name into an IP address. For example, www for use on the Internet, then typed the domain name, for example: yahoo.com then be mapped to an IP 202.68.0.134 eg. So the analogy to the DNS can use the phone book, where people we know by name to contact us should dial the telephone number in the phone. Exact match, the host computer sends queries in the form of a computer name and domain name server to the DNS, and the DNS is mapped to an IP address.

DNS structure

Root-Level Domains

Domain determined based on the existing skill levels in a hierarchical structure called the level. The top level in the hierarchy is called the root domain. Root domains are expressed by a period in which the symbol for the root domain is (â € œ.â € ??).


Top-Level Domains

In the sections below is an example of a top-level domains:

com: Commercial Organizations

edu: educational institution or university

org: Non-profit Organization

net: Networks (Internet backbone)

gov: non-military government organizations

Mila: military government organizations

num: No phone

arpa: Reverse DNS

xx: two-letter country code for (id: Indonesia, sg: singapore, au: australia, etc)

host Names
Domain name used with the host name will be created fully qualified domain name
(FQDN) for each computer. For example, if there fileserver1.detik.com, where fileserver1 is the host name and domain name detik.com is.

How DNS Works?
The function of DNS is to translate computer names to IP addresses (mapped). DNS clients called resolvers and servers called DNS name servers. Resolvers or client sends a request to the server name in the form of queries. Name servers will process in a way to check the local DNS database, contact other name server will send a message or failure if it turns out the request from the client was not found. The process is called the Forward Lookup Query, which is the demand of the client by mapping the name of the computer (host) to an IP address.
  • Resolvers send queries to the name server
  • Check the local name server to the database, or other contact name server, if found to be notified to the resolvers otherwise would send a message failure
  • Resolvers contact the destination host with the IP address given name server
conclusion
DNS is the result of the development of methods of finding the host name to an IP address on the Internet. In the DNS client (resolver) sends queries to the Name Server (DNS). Name Server will accept the request and map computer names to IP addresses Domain Name Space is a hierarchical grouping consisting of a root-level domains, top-level domains, second-level domains, and host names.

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