1.2. Firewall policies
The firewall policies specify the desired security state of your network. They outline rules and actions to take for different types of traffic.
Typically, the policies contain rules for the following types of traffic:
- Incoming traffic
- Outgoing traffic
- Forward traffic
- Specific services and applications
- Network address translations (NAT)
Firewall policies use the concept of firewall zones. Each zone is associated with a specific set of firewall rules that determine the traffic allowed. Policies apply firewall rules in a stateful, unidirectional manner. This means you only consider one direction of the traffic. The traffic return path is implicitly allowed due to stateful filtering of firewalld.
Policies are associated with an ingress zone and an egress zone. The ingress zone is where the traffic originated (received). The egress zone is where the traffic leaves (sent).
The firewall rules defined in a policy can reference the firewall zones to apply consistent configurations across multiple network interfaces.