How does DNS work?

DNS (Domain Name System) is a distributed database system used to map between domain names and IP addresses. DNS offers a special method to maintain and link these mappings in a unified whole.

On a larger scale, computers connected to the internet use DNS to create URL link addresses ( Universal Resource Locators ). Under this method, each computer will not need to use the IP address for the connection, but simply use the domain name (domain name) to query the connection.

Domain hierarchy model

To better understand the operation of DNS we consider the example and refer to the drawing below:

Domain hierarchy model

Active example of DNS:

Assuming PC A wants to access the website www.yahoo.com and the vvn server has not saved information about this site, the query steps will take place as follows:

• First PC A sent a request to ask the domain name server to ask for information about www.yahoo.com.
  Domain management server vnn sends a query to the top level domain server.
• Top level domain stores information about all domains on the network. Therefore it will send back to the server managing the domain name and IP address of the domain management server com (calling server com off).
• When the IP address of the domain name server is managed, server vnn immediately asks com server for information about yahoo.com. Server com manages all the websites that have com domain, they send information about the IP address of yahoo.com server to the server.
• Now the server vnn already has the yahoo.com IP address. But PC A requires www service, not ftp service or any other service. So the server continues to query to the yahoo.com server to request information about yahoo.com's www service management server.
• Naturally, when receiving a query, the yahoo.com server sends it back to the server and the IP address of the management server www.yahoo.com.
• Finally, the server will send the IP address of the management server www.yahoo.com. for PC A and PC A to connect directly to it. And now the server vnn has information about www.yahoo.com for future queries of other clients.