What is the successful phenomenon of the telnet port in Linux?

In Linux, using the telnet command can test network connections and whether ports are reachable. When you successfully connect to a specified port, you may observe the following typical behaviors:

1. Message of successful connection: When the connection is successful, you will see a message similar to the following.

Trying IP_address...
Connected to hostname (IP_address).
Escape character is '^]'.

This indicates that telnet has successfully connected to the target host and port, and you can now start interacting with that port.

Command Line Prompt: Once the connection is successful, you will see a simple command line prompt as shown below:

Connected to hostname
Escape character is '^]'.

At this point, you can enter commands for further interaction.

You can send and receive data: Once successfully connected to the port, you can send data in the terminal window and receive responses from the destination port.

Disconnect: To disconnect from the target port, you can press `Ctrl + ]`, then enter the `quit` or `exit` command, or simply close the terminal window.

Please note that these phenomena may vary due to the settings of the target host and port. If the connection fails, you may see error messages such as “Connection refused” or “Connection timed out.”