Exchanging domain names and ip addresses can make it easier for users to surf the internet, and they can also log in to many websites for enquiries. Let users surf the Internet more conveniently and live more conveniently. Dns refers to the computer domain name system, which is mainly composed of a parser and a domain name server.

DNS(DomainNameSystem), as a distributed database that maps domain names and IP addresses on the Internet, enables users to access the Internet more conveniently without having to remember IP strings that can be directly read by machines. The process of finally getting the IP address corresponding to the host name is called domain name resolution (or host name resolution). DNS protocol runs on top of UDP protocol, using port number 53. In the RFC document, RFC2 18 1 has the specification of DNS, RFC2 136 describes the dynamic update of DNS, and RFC2308 describes the reverse cache of DNS queries.

Each IP address can have a host name, which consists of one or more strings separated by decimal points. With the host name, you don't have to memorize the IP address of each IP device, just remember the relatively intuitive and meaningful host name. This is the function of DNS protocol.