Port is a free translation of English port, which can be regarded as the exit of communication between equipment and the outside world. Ports can be divided into virtual ports and physical ports, where virtual ports refer to the ports inside the computer or in the switch router and are invisible. Such as port 80, port 2 1, port 23, etc. Physical ports, also known as interfaces, are visible ports, RJ45 network ports on the computer backplane and RJ45 ports, such as switch router hubs. Phones using RJ 1 1 jack also belong to the category of physical ports.
Ports refer to some registers in the interface circuit, which are used to store data information, control information and status information respectively. The corresponding ports are called data ports, control ports and status ports respectively.
Port type
1, well-known port
Well-known ports are well-known port numbers ranging from 0 to 1023, of which 80 ports are allocated to WWW service and 2 1 ports are allocated to FTP service. We don't need to specify the port number when we enter the URL in the address bar of IE, because by default, the port of WWW service is "80".
Network services can use other port numbers. If it is not the default port number, you should specify the port number in the address bar by adding a colon ":"(half angle) after the address and then adding the port number. For example, if you use "8080" as the port of WWW service, you need to enter "URL: 8080" in the address bar.
2. Dynamic port
The range of dynamic ports is from 49 152 to 65535. It is called a dynamic port because it generally does not allocate a service fixedly, but dynamically.