what is dns

DNS stands for "Domain Name System". It is the system in the Internet responsible for resolving domain names into specific IP addresses. It acts as the "phone book" of the Internet and provides a way to map easy-to-remember domain names to computers that can Understand the functions of IP addresses.

DNS (Domain Name System) is the system on the Internet responsible for resolving domain names into specific IP addresses. It acts as the "phone book" of the Internet, providing the ability to map easy-to-remember domain names to computer-understandable IP addresses.

In the Internet, each device (such as computer, server, router, etc.) needs a unique identifier, which is the IP address (such as "192.168.0.1" in IPv4 format or IPv6 format of "2001:0db8:85a3:0000:0000:8a2e:0370:7334"). What people remember more easily is the domain name (such as "example.com"). The function of DNS is to find the corresponding IP address through the domain name, so that people can access resources on the Internet in a more convenient way.

When you enter a URL in the browser, the browser will send a DNS query request to the local DNS server. The local DNS server will first check whether the IP address corresponding to the domain name exists in its cache. If not, in the globally distributed DNS server hierarchy, the local DNS server will sequentially initiate query requests to the upper-level DNS server until it finds a DNS server that can resolve the domain name. Eventually, the returned IP address is cached by the local DNS server and passed to the browser, allowing it to initiate communication with the target server.

DNS is not only used for domain name resolution, it also supports other functions, such as MX record resolution in emails, reverse resolution, etc. Through DNS, we can use easy-to-remember domain names to access various resources on the Internet without having to remember complex IP addresses.

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