Types of Firewall

A firewall is a security tool that filters traffic, but not all firewalls work the same way. The difference comes down to where the firewall is placed and what it is protecting. The book draws a clean line between two types: network firewalls and host-based firewalls.

Network Firewall

A network firewall sits between two or more networks. Its job is to monitor the traffic that flows between those networks. Because it guards the boundary, it sees everything that tries to cross from one network into another — for example, traffic coming from the internet into a company's internal network. This makes it a central, shared line of defence for an entire network rather than for any single machine.

Host-based Firewall

A host-based firewall, in contrast, is installed directly on a single computer. It monitors only the network traffic going to and from that specific machine. It does not care about other computers on the same network; it watches only what enters or leaves the one device it protects. This is useful when you want individual protection for a particular system, even if the network around it has its own firewall. …