The root domain

There are 13 root domains and only a few mirrors in China. The root domain is responsible for returning the authoritative DNS address of the top-level domain name.Copy the code

The division of the domain

Industry division: com/net/gov/ country division: CN /jp/us baidu.com is a top-level domain (first-level domain) followed by second-level domain and third-level domainCopy the code

Domain server

A server that provides domain name resolution. Returns IP by domain nameCopy the code

Domain name Resolution Process

1. For example, I have a computer that needs to install broadband and access the Internet through an ISP(such as China Unicom). The ISP assigns a DNS. DNS can also be specified (e.g. 8.8.8.8). If you want to access a domain name (www.baidu.com), you need to obtain the corresponding IP address from the local hosts and local cache. 4. If you cannot obtain the IP address locally, you need to send a request to ISP DNS. If ISP DNS does not find either, 13 root domains or images will be requested. The root domain returns the server address of the top-level domain (the address of the baidu.com top-level domain is returned). 7. ISPDNS requests an address from the baidu.com top-level domain and returns the host IP address of www.baidu.com. 8. ISPDNS returns the IP to the client and caches it.Copy the code

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