What is DNS query? The principle and function of DNS query are explained in detail

in daily network access, we only need to enter a string of simple domain names to open the corresponding website, which is inseparable from a mature address conversion mechanism. DNS query is the core link of this mechanism, which is like a navigation system in the online world, silently completing the conversion of domain names and Internet Protocol Addresses. This article will deeply dismantle the definition, operation principle, practical function and optimization method of DNS query to help you fully understand this key technology that supports the normal operation of the network and understand the complete logic behind domain name access.

What is the basic definition of DNS query?

to understand the role of DNS queries, we must first clarify its core definition and significance, and clarify its positioning in the network access process.

1, the core essence of DNS query

DNS query is an address conversion request initiated by the client side to the DNS server in the domain name system. The core is to convert the user's easy-to-remember domain name into an Internet Protocol Address that can be recognized by network devices. Because the communication between devices in the network depends on the Internet Protocol Address, but it is difficult for users to remember complex number strings, DNS query assumes the role of "translator" and breaks down the barrier between user memory and network communication.

2, DNS query initiator

The initiator of

DNS query is usually the user's end point device, such as computer, mobile phone, tablet, etc., or other servers in the network. When the user enters the domain name in the browser, the end point device will automatically trigger the DNS query, without the user's manual operation. The whole process is completed quickly in the background, and in most cases the user does not perceive the obvious delay.

What are the operating principles of DNS queries?

The operation of

DNS query is a hierarchical and progressive request process, involving the cooperative work of multiple servers, rather than a single simple query.

1, recursive query execution logic

recursive query is a common mode of DNS query. After the end point device initiates a request to the local DNS server, the local server will be fully responsible for the subsequent query work. If there is a corresponding record in the local server cache, the result will be returned directly; if not, it will initiate a query to the root domain name server, top-domain level server, and authoritative domain name server in turn until the Internet Protocol Address is obtained and then returned to the end point device. The whole process is completely transparent to the user.

2, iterative query execution logic

iterative query is another mode of DNS query, after the local DNS server initiates a request to the root name server, the root server does not directly return the result, but informs the address of the next top-level domain server, the local server then initiates a request to the top-level domain server, and so on, until the Internet Protocol Address is obtained from the authoritative domain name server, and finally returned to the end point device.

What are the actual functions of DNS queries?

in addition to basic address translation, DNS query has many extended roles in network operation, supporting the stability and efficiency of network services.

1, simplify user network access operations

The most basic function of

DNS query is to simplify user operations, so that users do not need to remember complex Internet Protocol Address, just enter a memorable domain name to access the website. For example, users only need to enter "www.baidu.com", through DNS query can be converted to the corresponding Internet Protocol Address, greatly reducing the threshold for network access, so that ordinary users can easily use the network.

2, improve the stability of network access

DNS query can also improve the stability of network access. When a server corresponding to an Internet Protocol Address fails, DNS query can transfer the domain name resolution to the Internet Protocol Address of the standby server to achieve automatic failover. At the same time, some DNS servers will provide load balancing function to assign user requests to different servers through DNS query to avoid overload of a single server and ensure normal access to the website.

What are the common types of DNS queries?

according to the direction and content of the query, DNS query can be divided into many types, different types are suitable for different scenarios.

1, forward DNS query

forward DNS query is the most common type, which is the query that converts the domain name to Internet Protocol Address mentioned earlier, and it is also the main query type triggered by users when they visit the website every day. Forward DNS query is the basic link of network access, and almost all domain name access cannot be separated from the support of forward DNS query.

2, reverse DNS query

reverse DNS query is the reverse process of forward query, which converts the Internet Protocol Address to the corresponding domain name. This kind of query is usually used for cyber security verification. For example, the mail server will verify whether the domain name corresponding to the sender's Internet Protocol Address is legitimate through reverse DNS query, so as to determine whether the email is an email spam and improve the security of network communication.

5. How to optimize the efficiency of DNS queries?

DNS query efficiency directly affects the speed of network access, mastering some optimization skills can effectively improve the fluency of network access.

1, configure local DNS cache

most end point devices and DNS servers will have their own cache function. After configuring the local DNS cache, when repeatedly accessing the same domain name, there is no need to initiate a complete DNS query again, and the results are directly obtained from the cache, which can greatly shorten the query time. Users can turn on the DNS cache function in the device settings to improve the speed of repeated visits.

2 Choose a high-quality public DNS server

different DNS servers have differences in query speed and stability, choosing high-quality public DNS servers can improve the efficiency of DNS queries. For example, domestic 114DNS, Ali DNS, foreign Google DNS, etc., these server nodes are widely distributed, cache resources are rich, and can respond faster to users' DNS query requests.

To sum up, DNS query is the core technology supporting network access, from basic domain name and IP conversion, to improving network stability and ensuring communication security, all play a key role. By understanding the definition, principle, type and optimization method of DNS query, we can more clearly understand the underlying logic of network operation, and can also improve our own network access experience through reasonable optimization, so that network use is more efficient and smooth.