DNS resolution process [visit website]

DNS resolution website process

1. Check the local DNS cache to see if the cache has resolution data

windows

ipconfig /all

Liunx

dig www.baidu.comnslookup www.baidu.com

2. View the local hosts file [local domain name resolution file]

window and Liunx are both in the hosts file

3. The local fixed DNS server (router) finds 13 root domain servers [use iterative search]

4. The root domain is found to find the top-level domain, while the Baidu top-level domain is .com, and com finds the baidu domain name

so returns the result to you; return to the host

5. Establish a reliable TCP connection with Baidu server, three-way handshake

Three handshake

After the connection is established, keep-alive keep alive, the request returns information, and the response answers.Finally, the page is parsed through the browser