What is dns?
The abbreviation dns at the hearing today, all users of the Internet. But few know what exactly the meaning of these English letters. What is dns and how to decipher it?
A Domain Name System
The world wide web every web site has a personal IP address. All IP addresses represented as a sequence of four numbers and dots: 188.8.131.52. These numbers are called Okey. After the last digit not followed by a period. The IP address may include numbers from 0 to 255.
If we want to go to a site, we type the domain name and not IP address. Agree that combination of letters mail.ru much easier to remember than a long sequence of numbers. Here, the developers are thinking about how to tie these numbers to the text address?
The result was a developed system DNS Domain Name System. If we translate this phrase in Russian language, we get the name «domain name Service».
What is the domain?
When the Internet was in its infancy, each user had a file that was listed in the contact lists. When the computer is connected to network, and exchange data. But this exchange should be accelerated.
Long address divided into domains (segments), and they, in turn, divided into subdomains.
As the Internet emerged in the United States, the basic domains have English names:
COM – Organizations that do business
EDU – Institutions in the field of education
MIL – Military institutions
ORG – Private companies
NET – Internet service providers
The main (root) domains of other States represent a combination of two letters (EN).
Second level domains are names of towns and districts in an abbreviated form, and the third level comprises of the company and the company.
The point is a very important sign when it comes to domains. She plays the role of separator between the domains of different levels. But at the end of the name (address) point do not put.
Every single domain with a dot is the mark. Its length can not be more than 63 characters. The total address length is 255 characters.
For writing domain names are usually taken letters and the hyphen sign. Rarely used consoles other writing systems. Which letter will be written, large or small, is not important.
How DNS works
This unique system transforms long sequences of numbers of IP addresses to domain names. She also works in reverse, converting names to IP addresses. If the dns servers didn’t exist, Internet users would have to remember or write down is not simple names of the Roman letters, long strings of numbers separated by periods. Agree, not too rosy future?
If the dns server fails then domain names will not be converted into IP addresses. If you set any address of the site users will be shown an error page. The Internet connection is not disrupted.
Dns address is automatically allocated or specified in the Internet settings. To change data, you must go to the tab «Network connections». Then open a Protocol used for network maintenance. Here, please open the link «Properties» and specify the desired settings. In most cases, users prescribe the primary IP address and the second alternative.
Why you need a DNS server
Finding out what domain is and IP address, a reasonable question arises, what is the dns server. Dns servers are computers that store the list of objects within a single level of the Internet. They allow users to share information quickly.
Each network level has its own server on which you are carefully stored address data for the users separate segment.
For example, the user wants to find the right website. The service sends a request to the local server. If the data is, the client receives the answer that such a page exists. The browser receives the url and loads it.
If the local server does not have the necessary information, then the dns server makes a request of the computers of the highest order. This algorithm continues until, until the desired address is found.