Execution: ` firewall CMD — zone = public — add port = 8081/TCP — permanent`
The following error is prompted
`FirewallD is not running`
The reason is that the firewall is not turned on
solve:
1. Check firewall status:
Execute ` systemctl status firewalld`
Display dead status
2. Modify firewall status
Execute ` systemctl start firewalld`
Re execution ` Systemctl status firewalld ` check whether the modification is successful
3. Reopen the port
`Firewall CMD — zone = public — add port = 8081/TCP — permanent ‘
4. Turn off the firewall, or you won’t be able to access it
`systemctl stop firewalld`