First, check the open port of the local computer. You can use the netstat command.

1. Click the "Start" menu in the lower left corner of the screen.

2. Click "Run", or you can use the WIN+R key combination on the keyboard to quickly bring up the "Run" column.

3. Enter "CMD" in the "Run" column, and then click "OK".

4. The windows DOS interface pops up.

5. Enter "netstat" at the cursor, and then press Enter to display the port number of this machine.

Second, use software to view, such as Tcpview, PortReporter, etc. Take Tcpview as an example.

1. Double click to run the "Tcpview" program.

2. The program will automatically scan and display the port number.

Brief introduction of port number

The port number is the identification of the access server. The client can find the corresponding server through the ip address, but the server has many ports, and each application corresponds to a port number, through which the client can really access the server. In order to distinguish ports, each port is numbered.

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.