Which of the following types of firewall operates at the Network layer to examine incoming and outgoing packets?

Correct option is A

A packet filtering firewall operates at the Network layer of the OSI model, examining packets based on IP addresses, ports, and protocols. This firewall allows or blocks packets based on predefined security rules, providing basic but effective filtering at a low level.
Important Key Points:
1. Packet Filtering: Filters packets based on header information such as IP addresses, port numbers, and protocols.
2. Network Layer Security: By operating at the Network layer, packet filtering firewalls provide first-level security, defending against unauthorized network traffic.
3. Basic Firewall: Packet filtering is less complex and faster than other firewall types, suitable for foundational network security.
Knowledge Booster:
· Application-level Gateway: Works at the Application layer, examining traffic more deeply, typically for specific applications like FTP or HTTP.
· Circuit-level Gateway: Operates at the Session layer, verifying TCP connections without inspecting individual packets.
· Network Filtering: A general term, but not a specific firewall type, covering multiple approaches to controlling network traffic.