What TCP/IP layer does a packet filtering firewall work on?

John wants to implement a packet filtering firewall in his organization’s network.

What TCP/IP layer does a packet filtering firewall work on?
A . Application layer
B . Network Interface layer
C . TCP layer
D . IP layer

View Answer

Answer: D

Explanation:

A packet filtering firewall operates at the network layer of the TCP/IP model. It analyzes the headers of IP packets, which include source and destination IP addresses, protocol information, and port numbers, to determine whether to allow or block the packets based on predefined rules and access control lists (ACLs). This type of firewall does not perform deep packet inspection but rather checks the packet headers against the ACLs to make decisions1234.

Reference: The explanation aligns with the core functions of packet filtering firewalls as described in various sources, including the Enterprise Networking Planet and NordLayer articles, which detail how these firewalls interact with the IP layer to filter traffic12. GeeksforGeeks also confirms that packet filtering firewalls work at the network layer of the OSI model, which corresponds to the IP layer in the TCP/IP model4.