Today, we will look at the basic concepts of DNS and see how they are structured.
▶ Domain Name
A domain name is a regular naming scheme that allows people to use names composed of characters on behalf of IP addresses that are difficult for people to remember. It is called domain name in English and domain name if it is in Korean.
▶ Domain Name System (DNS) configuration
Domain Name System (DNS) is a collective term for Internet domain names. It is commonly referred to as DNS, which is understood to refer to a name server, but please note that the domain name server is only a component of the domain name system.
The Domain Name System was developed as a schedule database system to manage more systematically the management of the IP address information per host name in the initial internet through the hosts.txt file of the system. The Domain Name System is a distributed database system that is designed in such a way that each domain can manage its own domain data, and all domains that are distributed and managed can be linked to a single whole domain system.
A domain name system consists of the following three elements:
Ⓐ Domain Name Space and Resource Record
This is the definition of the data structure used by the domain name system. A domain name space is a domain name organization scheme that is defined to create and use names that do not duplicate domain names. This is usually the tree structure of the domain name system that extends from the root domain at the top. Domain Names In a system, a domain name has a unique value.
A resource record is a data type that can be set for a domain name. The domain name system as the database system uses the domain name as the key value and sets the necessary data for the domain name. The data of the domain name should be applied in advance with the promised data type and format. The resource record defines the kind of data that can be set in the domain name. In addition to A type records of well-known IPv4 addresses, the resource record type has various record types defined.
Ⓑ Name Server (Name Server)
The name server is a server program that holds the data of the domain and responds with the data that is retrieved by the retrieved data when receiving the data query of the domain name and its name from the external internet. The name server here refers to a pure name server that only sets the domain zone and does not have a recursive function. The name server mainly implements the database structure in internal memory and stores the data read through the zone file as domain zone data. There is also a name server that manages domain-zone data in an external, separate database system, and the nameserver implements the use of domain-zone data from the database system for DNS responses.
Ⓒ Resolver
A resolver refers to a routine in the form of a S / W library that performs data lookup of a domain name. The resolver receives the domain name and the record type to be inquired from the application and automatically searches the name server where the domain is set on the Internet, responds to the desired data, and returns the final result to the application. Because the domain name system is a distributed structure database, data is scattered around each Internet name server, not just one system, so you need a resolver to query it.
The original resolver was supposed to be implemented in the host system, but there was a problem that DNS query response traffic caused by each host resolver was excessive. At present, DNS traffic is insignificant compared to the capacity of the Internet backbone, but in the 1980s, the Internet copy size ranged from 56Kbps to 1.5Mbps, among which DNS traffic accounted for more than 20%. You will use a recursive name server (caching name server) to reduce DNS traffic.
Currently, Resolver is implemented as a recursive name server, which is a separate system with data caching function, for texture and query response of DNS query response traffic. In this case, the host also needs a resolver to handle the application's lookup request. When using a recursive name server, the host applies a stub resolver routine with only a simplified resolver function.
The above figure is an example of a concrete representation of three components of the Domain Name System.
Create the required domain name in the registered domain area and set the data for this domain name by applying the resource record type and its format according to the nature of the data. It is primarily written in the zone file format. Because the zone file format is defined as an Internet standard, a name server that implements most of the DNS standards can recognize and process zone files.
The data of the created domain zone is reflected in the name server, and can be viewed from the Internet. The remote resolver tracks the name server with the domain name and queries the data of the desired domain name.
I have learned about the basic concepts and components of DNS. We have found that, without any thought, we enter a simple action of typing in the address bar and pressing "enter" on the Internet through a very complicated process and linking to the desired landing page.
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