If you are not familar with firewalld and the firewall-cmd, check out our Getting Started article.

Let's say you want to configure firewalld to only allow connections from IP addresses 192.168.0.1 through 192.168.0.254. First, use the --list-sources option to determine if firewalld is configured with any sources. If --list-sources returns no output, this means that firewalld is not configured with any sources.

firewall-cmd --list-sources

Or the --list-all option can be used to see if there are any sources.

~]# firewall-cmd --list-all
public
  target: default
  icmp-block-inversion: no
  interfaces: eth0
  sources:
  services: ssh
  ports:
  protocols:
  masquerade: no
  forward-ports:
  sourceports:
  icmp-blocks:
  rich rules:

Here is how you would configure firewalld to only allow connections from IP addresses 192.168.0.1 through 192.168.0.254.

firewall-cmd --zone=public --add-source=192.168.0.0/24 --permanent
firewall-cmd --reload

The --check-config command can be used to ensure there are no configuration errors.

~]$ firewall-cmd --check-config
success

Now, --list-sources should return the following.

192.168.0.0/24

And --list-all should contain 192.168.0.0/24 as well.

~]# firewall-cmd --list-all
public
  target: default
  icmp-block-inversion: no
  interfaces: eth0
  sources: 192.168.0.0/24
  services: ssh
  ports:
  protocols:
  masquerade: no
  forward-ports:
  sourceports:
  icmp-blocks:
  rich rules: