For server/client architecture applications, such as web services, there is usually a server and a client.

If your computer plays the role of a client (as most computers do), then when you open a browser to access a remote server, the computer opens the connection between the remote port of 80 by default and the IP of the remote server, and the local port is randomly assigned;

On the other hand, if your computer provides web services, the local port is 80 (of course, you can change it to something else). Others will visit you through your IP+ port 80.

Different services use different service ports; The ports of well-known services are generally fixed; Such as telnet 23, ftp 20/2 1, dns 53, etc.

If your computer does not provide web services, but you find many connections to local port 80, it means that your computer has been infected with Trojan horses or viruses, please kill them in time.