What is a DNS domain name server? Explanation of core concepts and working principles

in the daily process of surfing the Internet, we only need to enter the familiar domain name to access various websites, without memorizing the complex Internet Protocol Address, which is inseparable from the support of a mature address translation system. DNS Domain Name Server is the core carrier of this system, which undertakes the translation of domain names and Internet Protocol Addresses, and is an indispensable key node in the Internet communication link. This article will comprehensively analyze the operation logic and value of DNS Domain Name Server from the core concept, hierarchical architecture, working principle to practical application, and help readers establish a clear understanding of this Internet basic service.

What is the core concept of DNS name server?

to understand the role of DNS name servers, we first need to clarify its basic definition and core functions.

1, the essential positioning of DNS name servers

DNS domain name server is a server dedicated to the domain name system. Its core function is to convert user-entered easy-to-remember domain names into computer-recognizable Internet Protocol Addresses. Since devices in the Internet communicate through Internet Protocol Addresses, and ordinary users have difficulty remembering long digital IPs, DNS domain name servers act as "translators" and build a communication bridge between users and network devices.

2, the core value of DNS name server

In addition to the basic address conversion, DNS domain name server also assumes additional functions such as load balancing, failover, and domain name caching. It can assign user requests to different server nodes to improve the speed and stability of website access; when a server node fails, it automatically redirects requests to normal nodes to ensure uninterrupted service; at the same time, by caching the resolution results of commonly used domain names, the time cost of repeated queries is reduced.

What are the hierarchical structures of DNS name servers?

DNS domain name server is not a single independent node, but a distributed system composed of multiple layers, which guarantees the efficiency and reliability of domain name resolution.

1, root name server

root name server is the highest level of the entire DNS system. There are only 13 root name servers in the world, which are responsible for managing the resolution authorization of top-level domains. When the local DNS name server cannot directly resolve the domain name, it will first initiate a query to the root name server to obtain the address of the corresponding top-level domain server, which is the starting point of the domain name resolution process.

2, top-level domain server

top-level domain server is responsible for managing various top-level domains, such as com, cn, org, etc. It will store the address information of the corresponding second-level domain name server. After receiving the authorization of the root domain name server, the local DNS domain name server will initiate a query to the top-level domain server to obtain the server address of the target second-level domain name, and further narrow the resolution range.

3, authoritative name server

authoritative domain name server is the official resolution server of the corresponding domain name, which stores the direct mapping relationship between the domain name and the Internet Protocol Address. When the local DNS domain name server obtains the authoritative domain name server address, it will initiate a final query to obtain the Internet Protocol Address corresponding to the target domain name, completing the core part of the entire resolution process.

4, local DNS name server

local DNS domain name server is a server directly connected to the user equipment, usually provided by the network service provider. It will cache the resolution results of the user's commonly used domain names. When the user initiates a domain name query, first find it in the local cache. If there is, the result will be returned directly. There is no need to initiate a request to the higher-level server, which greatly improves the resolution efficiency.

How does the DNS domain name server work?

DNS domain name server resolution process is a hierarchical query, step by step authorization process, each link is closely linked to ensure that users can quickly obtain the correct Internet Protocol Address.

1, recursive query phase

when a user enters a domain name to initiate an access request, the device first initiates a recursive query to the local DNS domain name server. Recursive query means that the local DNS domain name server needs to be responsible for the user's request, either directly returning the resolution result, or completing the follow-up query process on behalf of the whole process, the user does not need to participate in the intermediate link.

2, iterative query phase

if there is no corresponding domain name resolution result in the cache of the local DNS domain name server, it will enter the iterative query stage. It first initiates a query to the root domain name server to obtain the top-level domain server address; then queries to the top-level domain server to obtain the authoritative domain name server address; finally queries to the authoritative domain name server to obtain the target Internet Protocol Address. The whole process is a process of querying step by step and obtaining authorization in turn.

3, result caching and return phase

when the local DNS domain name server obtains the Internet Protocol Address, it will store the resolution result in the local cache, and set the cache valid period, and return the Internet Protocol Address to the user device. The user device establishes a connection with the target server with the Internet Protocol Address to complete the website access process; if other users query the same domain name in the future, the local DNS domain name server can directly retrieve the result from the cache to improve the resolution speed.

sum up, DNS domain name server is the core "translator" of Internet communication. From the essential positioning of the core concept, to the distributed design of the hierarchical architecture, to the recursive and iterative query of the workflow, every link serves the efficient conversion of domain names and Internet Protocol Addresses. It not only simplifies the user's Internet operation, but also ensures the stability and efficiency of Internet access. It is one of the basic services supporting the operation of the modern Internet.