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Testing involved the port number, as this summary:
Generally used is 1 to 65535.
Where 0 is not used, 1-1023 for the port system, also known as BSD reserved port.
0-1023: BSD reserved port, also known as system ports that only a privileged process system to use;
1024 to 65535 for the port users, is divided into: BSD temporary port (1024-5000) and BSD servers (non-privileged) port (5001-65535). among them:
1024-5000: BSD temporary port, the general application uses 1024-4999 to communicate;
5001-65535: BSD server (non-privileged) port, used to customize the user interface.