Analysis of URL

Summary of the URL

Component of URL – URL consists of protocol, domain name, path, query parameters and anchor points.

  1. agreement

HTTP uses port 80 by default, and HTTPS uses port 443 by default.

A domain name is an alternate name for an IP address used to access a website.

With the path can request the same server on different pages, the path is not necessary to have a suffix.

https://developer.mozilla.org/zh-CN/docs/Web/HTML

https://developer.mozilla.org/zh-CN/docs/Web/CSS

Using query parameters to request the same page, you can get different content.

http://www.baidu.com/s?wd=hi

http://www.baidu.com/s?wd=hello

Anchor points can be used to do the same content, different locations.

https://developer.mozilla.org/zh-CN/docs/Web/CSS# reference books

https://developer.mozilla.org/zh-CN/docs/Web/CSS# tutorial

Summary of the DNS

DNS matches domain names with IP addresses. Using the nslookup command, you can query the IP address corresponding to the domain name.

Summary of IP

An IP address is used to locate a device on the Internet. Each device connected to the Internet has its own IP address. IP addresses are classified into external IP addresses and internal IP addresses. The ping command is used to verify the connection to a remote computer. Ping Taobao.com will show different IP addresses in different regions.

Summary of the domain name

A domain name is another name for an IP address. A domain name can correspond to multiple IP addresses. This is called load balancing. An IP address can also correspond to multiple domain names, this is called host sharing.

  • classification

  1. .com is a top-level domain name

  2. Baidu.com is the second level domain name (commonly known as the first level domain name)

  3. www.baidu.com is a level 3 domain name (commonly known as level 2 domain name)

So www.baidu.com is a subdomain name of Baidu.com. IO is the domain name of github, userid.github. IO is the domain name of each user.