Centos firewall setting and port opening method

The CentOS firewall settings and port opening methods are as follows:

1. View firewall status: sudo firewall-cmd --state
2. To view firewall rules: sudo firewall-cmd --list-all
3. Open a port: Sudo firewall cmd -- zone=public -- add port=port number/tcp -- permanent , for example sudo firewall-cmd --zone=public --add-port=80/tcp --permanent
4. Reload firewall rules: sudo firewall-cmd --reload
5. To view open ports: sudo firewall-cmd --zone=public --list-ports
6. Close a port: Sudo firewall cmd -- zone=public -- remove port=port number/tcp -- permanent , for example sudo firewall-cmd --zone=public --remove-port=80/tcp --permanent
7. Turn off firewall: sudo systemctl stop firewalld.service
8. Turn on the firewall: sudo systemctl start firewalld.service

Note: --permanent The parameter indicates permanent effectiveness. If this parameter is not added, it will only take effect in the current life cycle.