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 web browsers 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 a private network or intranet where the DNS has advantages such as:
Easy, control is very easy because the user no longer bothered to remember the IP address of a computer is quite the host name (computer name).
Consistently, the IP address of a computer host name can be changed but not changed.
Simple, user only uses the domain name to search both the Internet and Intranet.
DNS functions can be equated with a phone book. Where every 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, it will use the host name. Then your computer will contact the DNS server to check the host name that you requested is how its IP address. The IP address used to connect your computer to other computers.
History of DNS
Before he used the DNS, HOSTS files using a 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 troublesome if there is the addition of one computer on the network, then we have to copy the latest version of this file to any location. With the increasingly widespread Internet network, it is more troublesome, finally made a design solution which replaces the function of the DNS in HOSTS files, with unlimited database size advantages, 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 it will be mapped to an IP eg 22.214.171.124. So, in 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 to the DNS server, then the DNS mapped to IP addresses.
Domain is determined based on the level of capability that exist in a hierarchical structure called the level. The top level in the hierarchy is called the root domain. Root domains are expressed based on the period in which the emblem for the root domain is (â € œ.â € ??).
In the sections below is an example of a top-level domains:
com: Commercial Organizations
edu: educational institution or university
org: non-profit organizations
net: Networks (Internet backbone)
gov: government non-military organizations
Mila: military government organizations
num: No phone
ARPA: Reverse DNS
xx: two-letter country code for (uk: England, sg: Singapore, au: australia, etc)
Domain name used with the host name will be created fully qualified domain name
(FQDN) for each computer. For example, if there are fileserver1.google.com, where fileserver1 is the host name and domain name are google.com.
How DNS Work?
The function of DNS is to translate computer names to IP addresses (mapping). DNS clients called resolvers and DNS servers called name servers. Resolvers or the client sends a request to the name server queries. Name server will process a way to check the local DNS database, contact other name servers or the failure to transmit the message if it turns out the demand of the client not found. The process is called the Forward Lookup Query, which is a request from a client by mapping the name of the computer (host) to an IP address.
Resolvers sends queries to the name server
Check to the local name server database, or contact another name server, if found to be otherwise notified to the resolvers will send a failure message
Resolvers contact the intended host using the IP address that was given the name server
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.