What is a common feature of many host-based application firewalls?

• A. They replace packet filters entirely.
• B. They are often combined with or used in conjunction with a packet filter.
• C. They operate only at wired networks.
• D. They require administrator-less operation.

Answer: (B)

Host-based application firewalls are designed to enforce control at the application layer and are typically used in combination with a packet filter. A packet filter handles broad, lower-layer decisions (IP addresses, ports, basic protocols) on the network path, while the host-based application firewall provides more granular control over which applications can create connections and how they behave. By working together, they deliver defense in depth: the packet filter blocks unwanted traffic at the network edge, and the application firewall blocks or allows traffic based on the specific application, user context, and data patterns. This combination is why the feature described—being used in conjunction with or alongside a packet filter—is the best fit.