The bad thing is that there is no 'one-size fits all' firewall that fits every situation. Now, the good thing about firewalls is that they keep our networks safe. If, for some reason, you wanted to change the default zone, you can easily do so by using the following command:įirewall-cmd -set-default=zonename Allow and deny by service If you wish to specify a zone, you simply add -zone=zonenameįor example, to see the external zone, use the following: ~]$ firewall-cmd -zone=external -list-all Services: cockpit dhcpv6-client mountd nfs rpc-bind ssh Here, the default zone is the public zone. Note that if you do not specify a zone, the default zone is queried. To display this information, use the following command: Many times, it is helpful to see what services are associated with a given zone. Generally, the default rule of a firewall is to deny everything and only allow specific exceptions to pass through for needed services. NOTE: I am using a RHEL 8.2 virtual machine for this demo. We see the preconfigured zones by using the following command: ~]$ firewall-cmd -get-zonesīlock dmz drop external home internal libvirt public trusted workĪs you see, the zones listed by default are: A zone is associated with at least one network interface ( eth0, for example). All about zonesįirewalld provides different levels of security for different connection zones.

Zone-based firewalls are network security systems that monitor traffic and take actions based on a set of defined rules applied against incoming/outgoing packets. At its core, firewalld is a zone-based firewall. With the introduction of the Red Hat Enterprise Linux 7.0 (RHEL) in 2011, iptables was superceded as firewalld was born. Most Linux systems made use of the iptables utility, however, a new technology was on the horizon. Today, we accomplish these same goals with the use of firewalls. In times past, when someone wanted to secure their possessions, they erected gates and fences to keep intruders at a distance. However, these connections are not inherently safe, and because of this, we have to put defensive measures in place to keep our location, information, and money protected.

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