HTTP communicates based on B/S architecture, and the server-side implementation programs of HTTP include httpd, nginx, etc. The client-side implementation programs are mainly web browsers, such as Firefox, Google Chrome, Safari, etc. In addition, the client's command line Tools include elink, curl, etc. Web services are based on TCP, so in order to respond to client requests at any time, the Web server needs to listen on port 80/TCP. In this way, the client browser and the web server can communicate through HTTP.