Which type of firewall inspects packets at the network layer?

Which type of firewall inspects packets at the network layer?

• A. Stateful inspection firewall
• B. Application-layer firewall
• C. Network-layer firewall
• D. Virtual firewall

Answer: (C)

A network-layer firewall operates at the network layer of the OSI model, which is responsible for routing packets across different networks. This type of firewall inspects the packets' headers, analyzing the source and destination IP addresses, as well as the protocols and ports used. By doing so, it can make decisions based merely on static information, allowing or denying traffic based on predefined rules. Network-layer firewalls have the capability to efficiently filter traffic at high speeds, making them suitable for environments where performance is critical. They do not delve into the payload of packets, which is where application-layer firewalls come into play, as they manage traffic based on the actual application data being transmitted. While stateful inspection firewalls maintain the context of active connections and provide additional intelligence, they still fundamentally operate at the network layer by inspecting packet flows over the connection. By focusing specifically on the network layer, the correct choice emphasizes the essential role of basic packet filtering that is utilized by many firewalls in various network configurations.

A network-layer firewall operates at the network layer of the OSI model, which is responsible for routing packets across different networks. This type of firewall inspects the packets' headers, analyzing the source and destination IP addresses, as well as the protocols and ports used. By doing so, it can make decisions based merely on static information, allowing or denying traffic based on predefined rules.

Network-layer firewalls have the capability to efficiently filter traffic at high speeds, making them suitable for environments where performance is critical. They do not delve into the payload of packets, which is where application-layer firewalls come into play, as they manage traffic based on the actual application data being transmitted. While stateful inspection firewalls maintain the context of active connections and provide additional intelligence, they still fundamentally operate at the network layer by inspecting packet flows over the connection.

By focusing specifically on the network layer, the correct choice emphasizes the essential role of basic packet filtering that is utilized by many firewalls in various network configurations.