You can use network IP scanning software to write the IP of the other party, and then scan upwards from 1.

Now let's talk about what a port number is. Ports are both potential communication channels and intrusion channels. Opening a port means that the computer has opened a window on the network. The method of hacker attack is to find the port opened by the server through manual scanning or scanning software, and invade or attack the server according to its corresponding vulnerability. Therefore, it is very important to know the ports.

Ports are roughly divided into three categories:

1: Known ports: From 0- 1023, they are bound to some services. Usually, the communication of these ports clearly indicates the protocol of a certain service. For example, FTP service opens port 2 1.

2. Registerd port: from1024-49151,it is loosely bound to some services, which means that many services are bound to these ports, and these ports also have many other uses. For example, many systems handle dynamic ports from 1024.

3. Dynamic and/or private ports: From 495 12-65535, these ports should not be allocated to services in theory. In fact, computers usually assign dynamic ports from 1024. Of course there are exceptions. SUN's RPC port starts at 32768.