How to check if a port is open on Linux

You can use the netstat command to check if a port is open on a Linux system.

The specific usage method is as follows:

1. Open the terminal and enter the command netstat -tln, which will display all the ports currently listening.
2. Look for the corresponding port number in the output. If the port number is found, it means the port is open.

Additionally, you can also use the telnet command to test if a specific port is open. Here is the specific method for using it:

1. Open the terminal, type the command “telnet IP address port number”, where the IP address is the server’s IP address to be tested, and the port number is the port to be tested.
2. If the terminal outputs “Connected to IP address,” it means that the port is open; if the terminal outputs “Connection refused,” it means that the port is closed.

Please note that the above method requires sufficient privileges to be executed on a Linux system.