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# DNS Protocol DNS (Domain Name System) is a distributed system used on the internet to translate domain names (such as `www.example.com`) into IP addresses (such as `93.184.216.34`). DNS serves as the internet's "phone book," allowing users to access network resources through easy-to-remember domain names without having to memorize complex IP addresses. Below is a detailed explanation of how DNS works and its key features. * * * ## How DNS Works DNS uses a hierarchical structure and distributed database to manage the mapping between domain names and IP addresses. Its core function is to resolve domain names. ### 1. **DNS Query Process** !(#) * **User**: Sends a domain name query request to the local DNS resolver. * **Local DNS Resolver**: Queries the root name server, top-level domain name server, and authoritative name server in sequence to obtain the domain name's IP address. * **Root Name Server**: Returns the address of the top-level domain name server (such as `.com`). * **Top-Level Domain Name Server**: Returns the address of the authoritative name server (such as `example.com`). * **Authoritative Name Server**: Returns the IP address of the domain name. * **Local DNS Resolver**: Returns the IP address to the user. ### 2. **DNS Record Types** The DNS database stores various types of records, the most common include: * **A Record**: Maps a domain name to an IPv4 address. * **AAAA Record**: Maps a domain name to an IPv6 address. * **CNAME Record**: Maps a domain name to another domain name (alias). * **MX Record**: Specifies the address of the mail server. * **NS Record**: Specifies the authoritative name server for the domain