Certified Network Defender (CND) — Question 139

John wants to implement a packet filtering firewall in his organization's network. What TCP/IP layer does a packet filtering firewall work on?

Answer options

• A. Network Interface layer
• B. Application layer
• C. IP layer
• D. TCP layer

Correct answer: C

Explanation

The correct answer is C, as a packet filtering firewall operates at the IP layer, examining the header information of packets to determine whether to allow or block them. Options A (Network Interface layer) and D (TCP layer) do not relate to packet filtering specifically, while B (Application layer) pertains to filtering based on application data, not packet headers.