Shulou(Shulou.com)06/01 Report--

In this issue, the editor will bring you about how to check the port status in Linux. The article is rich in content and analyzes and narrates it from a professional point of view. I hope you can get something after reading this article.

1. You can use "~ $netstat-anp" to see which ports are open.

(note: adding the parameter'- n 'will convert the application to port display, that is, addresses in numeric format, such as: nfs- > 2049, ftp- > 21, so you can open two terminals, one by one corresponding to the port number of the program)

two。 You can then view the program that applies the port through "~ $lsof-i:$PORT" ($PORT refers to the corresponding port number). Or you can check the file / etc/services, from which you can find out the service corresponding to the port.

(note: some ports cannot be found by netstat. A more reliable method is "~ $sudo nmap-sT-O localhost")

3. To shut down a port, you can:

1) disable the port through the iptables tool, such as:

"~ $sudo iptables-An INPUT-p tcp-- dport $PORT-j DROP"

"~ $sudo iptables-An OUTPUT-p tcp-- dport $PORT-j DROP"

2) or turn off the corresponding application, and the port will be closed naturally, such as:

"~ $kill-9 PID" (PID: process number)

For example, through "~ $netstat-anp | grep ssh"

There is a display: tcp 0 127.0.0.1 2121 0.0.0.0 * LISTEN 7546/ssh

Then: "$kill-9 7546"

This is how to check the port status in the Linux shared by the editor. If you happen to have similar doubts, you might as well refer to the above analysis to understand. If you want to know more about it, you are welcome to follow the industry information channel.

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