The TCP/IP protocol is the basis of the Internet international network, mainly including protocols such as TCP, IP, UDP and ICMP
To connect to the Internet, the operating system must install the TCP/IP protocol. The TCP/IP protocol allows different types of hosts with different operating systems to connect through the network.
The HTTP protocol in the TCP/IP protocol is used for browsing web pages, and the FTP protocol is used for Internet file sharing
An IP address is a 32-bit (or 128-bit) binary value used to represent a unique host in the network. Simply put, it is equivalent to each of our ID numbers.
| Classification | illustrate |
| Public network address (external network address) | An address that identifies a unique host on the Internet |
| Private address (intranet address) | An address that identifies a unique host on a local area network |
Because IP addresses are complex and difficult to remember, the Internet uses domain names to solve this problem. Domain names are a group of meaningful phrases used to identify IP addresses, such as www.baidu.com, etc.
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URL: Uniform Resource Locator (resource locator) is different from a domain name in that a domain name can only correspond to one IP address, usually a website, while a URL can precisely locate various resources on the network
Domain name: https://baike.baidu.com
URL:https://baike.baidu.com/item/url/110640
Generally, we enter the domain name (https://www.baidu.com/) in the browser to access the website and enter (https://www.baidu.com/index.html) to access the same page
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The web browser is responsible for translating various codes of web pages into colorful web pages according to code rules
| absolute path (physical path) | relative path |
| D:\wang\de.txt | "/"The root directory of the web application |
| https://www.baidu.com/index.html represents the absolute path of a url | "./" represents the current directory, "../" represents the parent directory |