DNS is the acronym for Domain Name System.
The acronym DNS comes from the English expression Domain Name System : that is, Domain Name System . This is a naming method used to name devices that connect to a network through IP ( Internet Protocol ) .
The DNS is responsible for linking information associated with the domain name assigned to each computer. In this way, it makes the binary identifiers related to the equipment acquire names that are intelligible to human beings, making it easier to locate them on the network .
DNS function
The DNS server , in this framework, hosts a database that stores domain name information. DNS protocols usually map a domain name to an IP address .
Suppose the site thisisanexample.com is located at the IP address 214.25.205.146 . DNS relates both data, allowing users to reach the IP address in question through the assigned domain name.
Main components
A DNS system is made up of three fundamental elements for its practical operation:
* clients phase 1 : the program that generates a request to the DNS server to know which IP address corresponds to a domain name . This program runs on the user's computer;
* DNS servers : they are responsible for resolving the client's request. If a recursive server does not find the address requested, it has the possibility of redirecting the request to another server;
* authority zones : this is a portion of the domain name space that is in charge of the DNS server, which may have authority over more than one, such as subdomains.
The DNS links information related to the domain name.
How DNS works
In everyday use, the user usually does not communicate directly with the DNS server since the names are resolved by the client applications, which include the browser and the email client.
When the user makes a request to find a DNS , it is sent to the operating system's DNS server , that is, to a local one, which looks for the resolution in the cache before starting communication with the outside world. Only then, if the response is not found, the request is sent to a DNS server or several, depending on the case, which is usually provided by the Internet service provider ( ISP ).
Outside of the options offered by our Internet service provider , we always have the possibility of using free domain resolution services or subscribing to a paid one to access a much higher speed and level of protection, something that companies usually do. big companies. However, most people are unaware of these alternatives and therefore use the DNS server provided by their ISP.
Server classification
DNS servers can be classified into three groups depending on the functions they perform:
* primary : they are also known as masters , and are those that store data in a namespace (a group of symbols used to organize various classes of objects, so that they can be recognized by their own names );
* secondary : they are those that receive data from the previous servers through a zone transfer. Another name they receive is slaves , since they depend on the actions of the primaries;
* local : its operation is supported by the same program, although it does not have the database to resolve the names. When they receive a query, they must refer to the appropriate DNS servers and then store the response to avoid the need to contact them if the same query is repeated in the future. These servers are also called cache .