Mastering Linux Security and Hardening

Adding ports to a firewalld zone

Having the service files is handy, except that not every service that you'll need to run has its own predefined service file. Let's say that you've installed Webmin on your server, which requires port 10000/tcp to be open. A quick grep operation will show that port 10000 isn't in any of our predefined services:

donnie@localhost services]$ pwd/usr/lib/firewalld/services[donnie@localhost services]$ grep '10000' *[donnie@localhost services]$

So, let's just add that port to our default zone, which is still the dmz zone:

donnie@localhost ~]$ sudo firewall-cmd --add-port=10000/tcp[sudo] password for donnie:success[donnie@localhost ~]$

Again, this isn't permanent, because we didn't include the --permanent option. ...