DNS domain name Conversion

The resource address of the information is generally given in the form of a domain name. How does the client know the IP address of this host?

The conversion from a domain name to an IP address is completed by the Domain Name Server (DNS) system. This system works in the Client/Server mode. The DNS process is similar to the telephone number service in the telephone system. To make a call, the sender must use the phone number, if you do not know the phone number of the other party but know the name, address, and city name of the other party, you can get the phone number of the other party from the phone number platform. When an application requests a host domain name to be converted into an IP address, the application becomes a customer of the domain name system. The software used by the client to send a domain name resolution service request is called a parser, the parser is both the service provider of the user program and the user of the Domain Name Server. It establishes a connection with the Domain Name Server and transmits the host name to the Domain Name Server, the host on which the server side provides the name resolution request service software is called the Domain Name Server. The domain name server returns the IP address of the host to the parser.

There are two types of Domain Name Server Resolution Methods: the first is recursive resolution. The parser sends a recursive query request to the server during the resolution process. The server first searches for the domain name in the region where it is located, the result is returned to the parser; otherwise, a request is sent to the root server, which is carried out from top to bottom by the root server. The second type is forwarding resolution. The parser requests a name server each time. When a name server cannot provide an answer to a query, the server in this request returns the address of the next request server, the parser resends a request to another name server. Therefore, no matter which resolution method is used, each parser knows at least how to access a name server and each name server knows at least the address of another name server.

In this process, if the domain name entered by the user is incorrect or cannot be found, the parser will prompt an error message. The entire process looks complicated, but because of the high-speed cache mechanism, all the recently found host addresses are stored in the high-speed cache, so the query process is very fast.

Of course, if you directly enter an IP address in the Uniform Resource Locator, such as "HTTP: // 10.67.53.5", the network will save the domain name conversion process. Article entry: dnbm responsibility Editor: dnbm