A brief analysis of Linux to check the firewall status and the status of the ports open to the outside world

1. Check the firewall status

Check the firewall status systemctl status firewalld

Start the firewall systemctl start firewalld

Disable the firewall systemctl stop firewalld

Start the firewall service firewalld start

If you cannot open

First use: systemctl unmask firewalld.service

Then: systemctl start firewalld.service

2. Check the status of open ports

Query the open ports netstat -ntulp | grep port number: You can check a specific port number

Check whether the specified port is open firewall-cmd --query-port=666/tcp

If the prompt is yes, it means it is enabled; if the prompt is no, it means it is not enabled.

3. External development port

Check whether the port you want to open is open: firewall-cmd --query-port=6379/tcp

Add the specified port to be opened: firewall-cmd --add-port=123/tcp --permanent

Reload the added port: firewall-cmd --reload

Check whether the specified port is opened successfully: firewall-cmd --query-port=123/tcp

Remove the specified port: firewall-cmd --permanent --remove-port=123/tcp

Summarize

The above is my introduction to checking the firewall status and the status of open ports in Linux. I hope it will be helpful to you!